Tue, 19 Dec 2023 03:39:48 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18050 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18050 Thu, 14 Dec 2023 16:22:36 +0000 greenfinger
I've got a wood burner installed in a builder's opening. Single wall flue into a flexible chimney liner. The thin steel closure plate is higher than the lintel in front - i.e. you can't see it when stood in front of the stove. I therefore often wonder how much heat gets "trapped" in that pocket of space behind the lintel, and subsequently escapes through the closure plate into the chimney void.

So I've been thinking about insulating above the closure plate using mineral wool and wondered what people think to the idea? I've not come across much info of people doing that. Seems sensible to me but perhaps I'm overlooking something.

I did mention it to the chimney sweep when he was last here and he was against the idea. Not sure how much I trusted his opinions though (on that and other things!). One of his concerns was the mineral wool combusting. I told him that in my limited knowledge it's not combustible but he wasn't having any of it!

Any thoughts?

Many thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18024 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18024 Fri, 17 Nov 2023 10:57:11 +0000 CJCurry
I'm in the process of renovating my house. It's a stone built, C16th, long, thin, detached off-gas house in the Yorkshire Dales National Park. It's been our family home for several hundred years and I've just taken it on, so it's a bit of a labour of love. It's getting sympathetically double glazed, insulated and generally made as energy-efficient as possible. I'm a tree surgeon and forester by profession, so have almost unlimited amounts of free firewood, which is a resource I'd like to use as my primary heat source. I've removed the very old oil-fired central heating system and designed a new system which I'd like to run by you for comment. Constructive criticism welcome. I've asked my usual plumber but because my needs are a bit non-standard they didn't really get what I'm trying to achieve.

Essentially, I have a massive 30kw water-jacketed woodburning stove in the big kitchen in the middle of the house. The hope is to burn this fully opened-up for an hour or two on a morning and evening, and keep it ticking over shut down during the day. There are also two smaller stoves with back boilers in the living room and dining room which will be lit in winter. This should fill the 2000l thermal store enough to keep the hot water and underfloor heating topped up constantly - see diagram. If I go away and don't light the stoves, the immersion heaters should kick in, or I'll set them up to be turned on remotely a day before I get back. Equally if the system can't cope with demand, the immersions will take up the slack.

To anticipate a few queries...
-All pipe runs will be in 28mm
-The thermal store is on the first floor and all stoves are on the ground floor, with pipework on a continuous gradient so it should be gravity-fed
-By the time I've finished all the renovations, there'll be seven bedrooms and five bathrooms, with potentially up to 15 people having hot showers when the house is full, hence the wish for a big unvented DHW cylinder rather than a conventional heat-transfer plate from the thermal store.


I'd appreciate it if the with experience of similar systems could sense-check this design for me. Thanks!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17800 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17800 Wed, 29 Mar 2023 11:26:35 +0100 Diarmid http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17998 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17998 Wed, 18 Oct 2023 19:05:47 +0100 LouiseSJPP Situated in a ground floor living space of 20m2, the prime function for the unit is to reduce humidity of the house built into a hillside, in a forest.
The second function is to provide background heat. As we spend some months away from home, having a heat source with a drying function to switch on automatically will protect the house when we're not there. When we are there, we have a boiler stove in that space, but at 5kW to room (plus 10 to water which looks after the rest of the house) a bit of heat at the other end of the space will be useful.
The third function is to provide some relief from summertime extreme temperatures and high humidity, as we've had some very unpleasant episodes recently.
The house is double glazed and the thick stone walls seem to provide a reasonable degree of insulation. I'm thinking 1 or 2kW of electrical input giving maybe 2.5 or 5kW of heating / cooling may be about the right size.
Can anyone offer advice, opinion or experience on how to size, where to buy, who might install it.
We're in Valcarlos, Navarra.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980 Tue, 03 Oct 2023 18:41:20 +0100 DannySheffield
We need a new bathroom and the fitter has strongly recommended we replace the heating system first as a) it is likely to go wrong and need work which might well involve digging into walls etc, so it's better to do that before we have a new bathroom (and plastering in other parts of the house) done. b) switching to a combi boiler would free up much-needed space in a relatively small bathroom.

I'm aware that we won't be on a gas boiler forever. My question is - is there any benefit to maintaining space for the hot water cylinder in the bathroom on the basis that we might need to move back to tanks if we move to e.g. an air source heat pump? The heating engineer said that's probably 20 years away in our 1930s house. We have a second (120 litre) tank in the crawlspace, which we'd keep either way (just because it's too much hassle to get it out!).]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17976 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17976 Mon, 02 Oct 2023 13:25:46 +0100 LouiseSJPP
I'm in northern Spain, living nearly off-grid. I'm installing a back-boilered wood burner and wish to connect it to a 6 bar max steel 100 litre cylinder fitted with one coil, situated two floors directly above the stove. This will be the primary buffering circuit, and from there will run the central heating system. I'm intending to use the coil for the heat input to minimise thermal inertia and the water jacket to run the sealed heating system.

The first question is vented or sealed for this primary circuit? Code, in Spain, it seems, calls for sealed. I'm prepared to ignore this if I cannot see a way to guarantee safety without a vented system.

The stove (Flamma 14CS, 15kW, of which 10kW to water) is designed for either. It has a cold water flush in case of overheat. I have no documentation on how this works and frankly, I don't hold much faith in it. Where does it flush to, and if the flush is internal, what drives the flush through the existing pressure in a sealed system??

If I vent it, I need to choose gravity or pumped. If gravity, protecting against power loss is a null issue. I have a 5m vertical run of flow and return, but the cylinder I already have (Kospel SWK 100) is top-feed to both sides of the coil, which acts a little against gravity flow. I'm guessing if I insulate the vertical flow pipe run and leave the return unlagged copper, it will help maintain the flow.

Either way I understand I need an anti-condensation valve in the primary circuit, and in a sealed system would fit a magnetic filter / charge point and an expansion vessel. Or I could buy a ready-made unit which has these components in it. Plus pressure relief valve, auto-bleed valve and drain point.

Could anyone advise / discuss / guide me please? I need to get this right, I don't want any accidents or a system which doesn't work well.

Background: I was a professional engineer and have a fair bit of plumbing experience, but it doesn't extend to uncontrolled heat sources, hence my wariness and questions.

Edited: there was a typo in the make of stove, here is a link to the relevant pdf::

https://piecepolska.pl/data/UserFiles/Image/Flamma_instrukcja.pdf]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17967 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17967 Thu, 21 Sep 2023 20:49:35 +0100 tony
I said insulate the floor 150mm 100mm batts with 50mm EPS, and IWI 80mm PIR, draughtproofing, secondary glazing, insulate bay roof

What is the difference gas heated 7 days and 7 evenings 21C, night time 14C

Any guesstimates or do we need more info]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17933 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17933 Fri, 25 Aug 2023 17:42:54 +0100 djh http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17938 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17938 Fri, 01 Sep 2023 14:09:18 +0100 PaulEdwin
I will leave the refurbishment of our heating system for a future owner but wanted to start a discussion to explore how this heating product is best dealt with for a low carbon house.

There are three options that I have thought of, starting with the first – rip out the ducting and replace the gas heater with an air source heat pump and new radiators (and all the new pipework!). This would be a disruptive building operation, not only due to the routing of new pipework, but also the removal of the vertical ducting between ground and first floor would then require substantial redecoration.

Could a heat exchanger replace the gas heater? This would need new heat extraction ducts installed in the loft and ground floor ceiling spaces. The permeability of the building envelope may have to be checked and remedied if leaking. There is also a question of whether the existing supply ducts are correctly sized.

For my third option I wondered if an air-to-air heat pump could replace the gas heater and supply warm or cool air through existing ducts? This would avoid the need for an extraction system as above.

I forgot to mention that we have 8kW capacity solar panels installed on a SSW facing roof.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17915 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17915 Wed, 02 Aug 2023 21:40:44 +0100 Victorianeco
Just the last two days it appears my circulation pumps are both stuck on and the pressure relief valve (there appear to be 3) one of which seems to be bypassing water into the tundish....

The temperature seems to be at 57C when it is usually set to 50C...

What's the fault finding process? Never had an issue in 8 years previous, the only thing I can think of recently was draining the heating system to disconnect a rad. But no other issues.

Thoughts please]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17916 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17916 Fri, 04 Aug 2023 19:58:47 +0100 Diarmid http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17920 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17920 Sun, 06 Aug 2023 18:33:46 +0100 greenfinger
Sorry to return so soon with another wood stove question... This time it's about multi-fuel (MF) vs wood only (WO) stoves. From the reading I've done, there seems to be mixed opinions on whether a WO stove performs better than a MF stove, when burning wood only.

****Open Grate****. One of our shortlist stoves is the ACR Earlswood III and Astwood II. Both are MF and have grates with permanently open slots. See below for pics. The stoves tick a lot of boxes for us, but the grate puts us off. The manufacturer has said that it won't affect performance, so long as there's a good bed of ashes. But logic and the opinions of some on the net would perhaps suggest otherwise.


****"Hybrid"****. I used the term "Hybrid" in the title to refer to stoves like the Clearviews and Woodwarm Fireviews (others too I'm sure), which have riddling grates which can be put into a closed position and provide a flat bed. But there's still gaps between the bars so it's not a truly solid bed. And whilst the primary air can be closed (at least I know it can on the Woodwarm), I'm not sure if that totally prevents air getting through. A Woodwarm Fireview Eco is a contender.


****Wood Only.**** Another contender is the Dik Geurts Ivar 5. True wood only burner with vermiculite bricks on the bottom.


Any thoughts on the three types and how relevant or important the grate/base situation is for wood only, would be most appreciated. And just to add, I've read that a bonus of the MF and Hybrids is that the Primary Air coming in beneath the grate can be very helpful getting the fire going. Yet on the other hand, a WO without the grate and ashpan means a larger firebox.

Over to you guys!

Many thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17914 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17914 Tue, 01 Aug 2023 15:48:02 +0100 john.connett
Problem: The boiler is in the kitchen at the front of the house and the outdoor unit of the ASHP would need to go in the back garden. How to connect them with Uponor Ecoflex Thermo Twin HP, a large diameter insulated pipe for hydraulic, electrical and electronic connections?

The house was built in 1995 and has a concrete beam & block ground floor. My ideal solution would be to run the pipe under the house and up through a core-drilled hole in the kitchen floor. There is a kitchen unit close to the boiler and if it surfaced under that it would be almost invisible except for possibly some boxing at the back of a cupboard.

The excellent technical support at Uponor suggest that it is technically feasible but cannot identify a contractor that could do the work. They are only aware of contractors that undertake commercial/industrial projects.

The core drilling is feasible (although I don't know the Building Regulations aspects). I know that builders have put basements and wine cellars under existing houses. Others have sprayed thermal insulation under suspended floors. If a drain under my house broke I imaging there would be somebody that could fix it.

I really want to avoid the disruption of moving out furniture, ripping up carpets and floorboards and running large bore, insulated pipes up the outside and through the fabric of the house. If I can't avoid that aggravation I might just scrap the whole project!

With heat pumps set to become a common replacement for gas boilers, insulated pipe connections under the ground floors of houses without basements doesn't seem such an outrageous solution.

Has anyone achieved something similar?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17912 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17912 Mon, 31 Jul 2023 13:30:15 +0100 greenfinger
We're looking to have a wood stove installed. It will go into the corner of a room, at 45 degrees to the walls. Both walls are external, cavity, with plastered block / brick on the inside.

One installer has said so long as the two back corners are 100mm minimum from the walls, there won't be a problem with blowing the plaster.

But another has said it is best to follow the stove guidelines for distances to combustibles (even though the wall isn't combustible; but to prevent blowing) - which in our case would be 400mm.

Quite a difference! Would anyone mind sharing your thoughts on which sounds most realistic?

Many thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696 Sat, 14 Jan 2023 18:47:52 +0000 maxsm
How deep will I need to dig down to end up with a new floor at the same level as the current concrete floor?

After digging down I understand the layer order will be: 300mm insulation - DPM - concrete - 60mm wet UFH in screed - 15mm engineered wood floor. Is this in the correct order? Am I missing any layers? What thickness will the concrete be?

In the short-term the wet UFH will be powered by a gas combi-boiler but I may end up with an air source heat pump and/or solar water heating in the future. Is there anything in terms of plumbing/thermostat set-ups I should do now to ensure the UFH is compatible with my future energy plans?

Hope all that makes sense, any advice much appreciated, thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17878 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17878 Mon, 26 Jun 2023 11:03:26 +0100 lineweight
My understanding is that some years ago, there was a quite big gap between the efficiency of AS and GS, but that this has closed considerably in the meantime.

Meanwhile, GS remains a fair bit more expensive to install.

So, is GS something that is only worth even thinking about on larger new-build projects, ones where a garden area is available, and ones where the budget is fairly generous?

Or are there other scenarios where it's worth consideration?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17870 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17870 Tue, 13 Jun 2023 11:09:59 +0100 mitchino
I'm wondering whether now is the time to get a heat pump, as it looks like we can apply for grant funding from the Scottish Government of £7500 plus another £1500 because we are in a rural area.

Initial Questions:

The oil combi is the 25/32 kW model. What size of heat pump would we need?

I assume we would need an air to water heat pump - can the water tank be located outside of the house - we have a lean-to outhouse, can it go in there?

How far from the tank can the heat pump be located, and is this best positioned in a sunny spot with little wind?

The house has 15 radiators, plus two woodburners which we light when we want save oil. We would want keep the radiators, installing underfloor heating would be too much to deal with. If possible we would like to also avoid having to double the size of the radiators. Is there a system that we could get that would just be a straight swap with the oil combi?

Is it a condition of the grant application that the house has to have a certain level of insulation etc? Some parts of the house are well insulated, other areas are not.

As I said, just replacing the oil combi would be up to £5000. Roughly, what would be the cost of a heat pump and tank installation before the grant is taken into consideration?

Anyone with recent experience doing something similar?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17794 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17794 Fri, 24 Mar 2023 17:23:16 +0000 PeterWat
Background is living in a 1920s house - detached, semi-rural position, mostly solid brick walls; double glazed and some loft insulation; suspended timber ground floors. So far, bills for our gas CH/gas cooking/gas DHW are still not horrendous. Two advantages we have are south facing main windows, so a lot of solar gain; and one small woodstove, costing nothing to run (as we have a firewood source, coppiced and processed ourselves, seasoned when cut, stored for minimum 2 years under cover and well ventilated).

We have so far resisted going for expensive EWI and floor insulation. Partly because this would be very difficult and disruptive (and would cover up period features), and partly because we may be moving anyway; and the trend locally is for developers to demolish and rebuild (or gut and massively extend) many older houses that come on the market. So any retrofit insulating we did might have a very short life.

All that said, our gas boiler is over 15 years old and the decision is either (1) replace like with like; or (2) spend more on a heat pump. The latter would be doing the "right" thing - by current national advice - but is it?

On (2) all the usual advice says no - not worth doing unless the house is super-insulated as well.

Am wondering, however. In our situation, might it be worth considering an ASHP that would be considered undersized; keeping the existing radiators; and topping up heat in cold weather by plug in convector heaters? An expensive option, but would it remain so?

In the UK, conventional wisdom (at least, in the chattering classes) suffers from a deeply ingrained belief (dating from the 1950s) that gas heating is cheap, electric is expensive. I wonder though if this will soon be all wrong? Solar and wind power costs are tumbling but electricity seems likely to stay expensive due to the high costs of maintaining back-up generation (or energy storage) for periods of low generaion by renewable sources. On the other hand, the costs of fossil fuel power (or natural gas replacement by hydrogen) may get even more expensive. (For climate reasons they certainly ought to be).

Alongside all that, construction materials- and wage- inflation is simultaneously making effective insulation much more expensive.

So in future, might it become a valid strategy to leave some older, period houses poorly insulated, use a smallish ASHP for background heat, and bite the bullet of topping up with old-tech plug in heaters to heat key rooms on cold days?

Obviously not the ideal solution from a climate perspective - but in the (post mid-century) future we may have surpluses of renewable electricity, with significant consequences for relative prices.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17859 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17859 Thu, 08 Jun 2023 08:11:21 +0100 gustyturbine http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17839 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17839 Fri, 12 May 2023 18:05:37 +0100 tony http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17832 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17832 Wed, 10 May 2023 09:32:18 +0100 Dan Barlow
Its a 210L Advanced Appliances multi fuel thermal store, its connected to Ideal 40kW combi boiler which also still supplies some of the hot taps and a fairly old 14kW (5 to room, 9 to water) Hunter Herald stove. The TS runs my central heating (radiators and underfloor) and the remainder of the DHW (mainly the bath). I will use the immersion heaters too once solar is fitted.

All seems to be working generally as it should it terms of controls, when the stove is lit the pump runs and depending where the thermostats are set the boiler switches off.
However the TS is suppose to operate at 75-80 degrees according to the instructions, but im struggling to get it up to that temperature using the boiler or the stove, 60-65 is more realistic. The boiler is set on max temperature (80 degrees) but unless i run it flat out for hours on end the TS seems happier at around 65 degrees.

Im not sure if i was expecting too much from the back boiler stove but even after several hours with a good fire the output temperature is still only 60 degrees. The TS has a blending valve which controls the flow back to the stove which according to the instructions should be set at 55-60 degrees. It is a multifuel stove so maybe im not getting anywhere near the maximum output burning wood and would need to burn coal which im reluctant to do. Ive experiments with various pump speeds for the stove pump and also tried closing the valves to the heat leak radiators which is plumbed between the flow and return but im still not able to achieve more than 60 degrees.

Any help or advice would be much appreciated

Details of the Thermal Store:

https://www.youtube.com/watch?v=UX1O1kcvo1Q&t=13s

https://www.advanceappliances.co.uk/product/70-multi-fuel-universal-thermal-store-sfuts/]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17825 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17825 Fri, 28 Apr 2023 16:34:15 +0100 TigoDog
I'm helping my dad convert a 19th century hay barn into a 3 bed home that he'll live in. We're aiming for Band A EPC, so a very high level of insulation and air tightness, if not quite PassivHaus standard.

We effectively have a blank slate, so I'm interested in the GBF hive mind's opinion on the best heating solution. We are expecting to use an air-source heat pump, and I know the most commonly done method is an air-to-water system, heating water for UFH and general use. However, there is no existing wet heating system and I'm interested in air-to-air systems, particularly ducted systems (not wall mounted units). My thinking is that it should be more efficient to use the warm air created by the ASHP to heat the home directly, rather than losing energy in converting warm air to warm water. Also, UFH is expensive to install and ducted air should be cheaper(?). I'm also interested in how it could interact with Mechanical Ventilation. I imagine it would add complexity, but for the money I've seen quoted for UFH, I'd guess you could get a very high-end warm air/ventilation setup.

I know warm air systems were wide spread in residential buildings in the 70s - but were not popular as I understand it. They are common in commercial buildings (HVAC) and I assume they have come along way in the last 50 years, but most contractors I speak to seem to be pushing wet UFH. I'm trying to understand if this is just 'what they're used to' installing, more profitable, or if it is genuinely a better solution.

I appreciate he'd need a separate solution for hot water if we use the warm air system. He has space for solar, or if not, would an electric water heater would do the trick, or would that negate the efficiency gains? I've seen this system which does both in another thread, but according to the Daikin installer I spoke to, it isn't yet available in the UK market. https://www.daikin.eu/en_us/product-group/air-to-air-heat-pumps/multiplus.htm

My dad is relatively open to both options, but I wouldn't want to push something on him that doesn't work well, or 'feel nice'.

The barn is in the South of England (Berkshire). I include plans, which I have permission to post.

I'd welcome your opinions, or alternatively suggestions of contractors that can help.

Thanks in advance!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17790 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17790 Tue, 21 Mar 2023 09:01:16 +0000 revor
https://bsee.co.uk/pump-industry-urges-government-clampdown-on-non-compliant-central-heating-pumps/

Rather worrying this is happening and unnoticed and reminiscent of the fake electrical cable scandal of a few years ago. These sort of imports just undermines our own manufacturers. To put on a CE marking to indicate the product meets European conformity when it actually means China Export is taking the proverbial.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17785 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17785 Sat, 18 Mar 2023 16:46:52 +0000 djh
The radiant heater is a Steibel-Eltron IW180, which looks the same as an IW120 but has three 600 W bars. SWMBO has decided that it might be nicer to have some kind of panel heater or radiator instead of it, in approximately the same place. I'm happy to go along with this (SMBO), so I'm looking for any suggestions as to which heater to pick. I don't know much about the subject. I'd like wall-mounting, or wall stabilised anyway. Radiant panel or convector? Desirably no fan or other noise. Any form of built-in storage worthwhile? Any thoughts about reliability of particular models or brands? Dust traps? Appearance? Oh and if it has any smarts, then are they accessible to third-party control systems such as Home Assistant or IFTTT etc?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17781 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17781 Thu, 16 Mar 2023 12:45:51 +0000 greenfinger
Back again with another insulation question. I've came across a couple of examples of people pushing PIR further into the void between rafters (but not so far as to impede the airgap behind for ventilation) rather than flush with the rafter face. Looking into it, I found this was done on purpose to create a gap between those between rafter pieces of insulation and the perpendicular insulation installed beneath to the underside of the rafters. These airgaps apparently create reflective radiation and increase the effectiveness.

Just wondered what people think of this principle and whether it is right or not?

And if the idea does have merit, what would the minimum amount of air gap needed be to have any worthwhile effect? Would 5mm/10mm do anything?

Many thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17764 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17764 Thu, 02 Mar 2023 09:05:24 +0000 jhsigma http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17750 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17750 Wed, 22 Feb 2023 20:29:05 +0000 minisaurus
I don’t think radiator size would be an issue in most houses in most parts of the Uk, if one uses the heat pump in the way one does here in Scandinavia.

This is because the water temperature to the radiators is determined by the outdoor temperature (sensor) and the type of building (these are parameters you program into the pump).

For example, today, where I live it’s around 3+ degrees outside, the temperature the pump is sending to our radiators cycles between 35 and 45 degrees and we enjoy 20.5 degrees indoor temp (at the temp sensor). Our house is in no way super insulated.

One difference to the Uk gas boiler approach, is that the pump runs 24/7, so lower radiator temperatures work with this approach.

Our pump is EAHP, and with outdoor temperatures around 0 degrees and higher, the electric “booster” element hardly ever runs for space heating.

So, I reckon, with the relatively high winter temperatures in the Uk, and the correct configuration, you could run an ASHP economically without changing the radiators.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17736 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17736 Fri, 10 Feb 2023 12:21:15 +0000 GreenPaddy
-------------------------------
Here’s a new air to air heat pump with a HW cylinder. Not got a lot of info about it’s efficiency. Sounds good in theory!

https://www.daikin.eu/en_us/product-group/air-to-air-heat-pumps/multiplus.html

---------------------

It seems to me to be an excellent solution for certain situations, and develops on the experience of "owlman", and others, whereby not a lot of space heating is required, but direct electric immersion is used for DHW generation.

I've seen a number of questions about simple air-to-air for space heating, but if only there were a way to get DHW too.

Not sure about the price, as like bogal2, there doesn't seem to be that much info on it on Google, but perhaps worth discussing, following up on?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16867 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16867 Fri, 01 Jan 2021 19:04:38 +0000 Ed Davies
https://www.theguardian.com/environment/2021/jan/01/avoid-using-wood-burning-stoves-if-possible-warn-health-experts

“Campaigners and health experts are calling on people who have alternative heating not to use their wood burning stoves this winter amid growing concern about their impact on public health.

[…]

Now experts at the Asthma UK and British Lung Foundation Partnership are asking people with wood burners only to use them if they have no alternative source of heat.

“We know that burning wood and coal releases fine particulate matter (PM2.5) – the most worrying form of air pollution for human health,” said Sarah MacFadyen, head of policy at the charity. “It’s therefore important to consider less polluting fuel options to heat your home or cook with, especially if coal or wood is not your primary fuel source.” ”]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17740 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17740 Sun, 12 Feb 2023 13:26:59 +0000 ecosar I have had my wood boiler/range system heating CH & DHW for about 6 years. I have a thermal store.

increasingly more often the loading valve ESBE ltc 200 cycles on and off (I assume it is the pump I can hear), in a manner that I believe to be a servicing option, manually activated by turning the adjuster the opposite direction to normal. I am not turning the knob, but do wonder if it has somehow got turned. I have lost the manual and cannot find ltc200 on Ebse site.

The loading valve pump is activated by a flue stat, which I can adjust.

I have struggled to get an engineer out for several years and am wondering if any one here knows about loading valves and can help me work it out?

Thanks,
Sarah]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17429 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17429 Thu, 24 Mar 2022 17:02:53 +0000 owlman The heat pump industry itself was perhaps somewhat to blame in that it continued to label A/A as Aircon, a more canny approach from this industry may have been to label them as " air source reverse cycle heat pump " which may have got them included in the initial heat pump plan.

I came across this recently from BESA :-

APPLICABLE VAT RATE ON HEAT PUMP INSTALLATIONS
The purpose of this technical bulletin is to advise members of changes to the VAT rate
announced in the Chancellor’s Spring Statement of 23rd March 2022.
1. BACKGROUND
In July 2014 HMRC introduced a scheme for applying a reduced rate of VAT of 5% on energy
saving materials and heating equipment. It followed on from the enhanced capital allowances list of
previous years whereby heating equipment which featured on that list could have a 5% VAT rate
applied when the products were installed in domestic situations. The move was designed to
encourage the uptake of energy efficient heating systems such as heat pumps in retrofit
applications.
In October 2019 the rules were subtly changed to incorporate a “60% test” that must be applied for
the reduced rate to be used if certain social policy conditions are not met.
The Spring Statement of 23rd March 2022 has reversed that 2019 ruling as from 1st April 2022
meaning that the social conditions and 60% requirements no longer apply at all. This has been
implemented to incentivize homeowners to install energy saving heating materials as part of a
wider package of Government measures targeted at improving energy efficiency and driving the
decarbonisation of heat agenda.
The zero rating applies to installations of these products and therefore cannot be applied by sellers
of equipment only.
At this moment in time the zero rating can only be used by contractors in Great Britain as the EU
need to agree to this move for Northern Ireland. HMRC assured us that they are working on this
being a UK wide initiative as soon as possible.

2. VAT NOTICE 708/6 – CONFUSION OVER DEFINTIONS1
In February 2021 an amendment to clause 2.17 Air source heat pumps was made to correct a
mistake where air source heat pumps of the split air conditioning type had been specifically ruled
out from the scheme. There remained a large element of confusion across the sector, however,
and the issue persisted. After extensive talks between the BESA and HMRC the guidance has
been updated to clarify the applicability rules and allow air source reverse cycle heat pump air
conditioners in the same way it applies for monoblock heat pumps.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17693 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17693 Tue, 10 Jan 2023 20:10:03 +0000 eniacs
Weve a 12'000L pool in the garden that is dormant in the winter. Its temperature slowly follows ambient, it will take weeks to get down to 5 deg and then weeks to go back to 10 deg too.

Basically Im thinking to use a heat pump to cool the pool water and heat the house. The heat input to the pool would be able to be PLC choosen, ie if the air temp is above pool water temp then run a fan coil and pump to "warm" the pool water from ambient air.

I know its a drastic solution to a simple problem of low COP but my mind keeps going back. Maybe its the engineering challenge.

Has anyone seen a similar project?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17643 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17643 Wed, 16 Nov 2022 11:36:06 +0000 Peter_in_Hungary
Some thoughts

Heat load for the coldest month (kWh) / 30 = CH power demand for a day

CH power demand for the day / (how many hours ? ) = size of heat pump for CH.

DHW is fairly constant throughout the year so a daily consumption is easy find so –

DHW power demand for the day (kWh) / (how many hours ? ) = size of heat pump for DHW

But is the CH load on top of the DHW load or do you target the hours run so that e.g. CH needs 10 hours run time and DHW needs 5 hours run time = 15 hours run time a day so that the heat pump needs to be sized only for the greater of either load.

Playing with the target run times for each of the CH and DHW will alter the planning size of the heat pump.

But what should the target run times be ?? And how much spare should capacity be built in ?

Or have I got it all wrong?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17685 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17685 Sat, 31 Dec 2022 22:44:47 +0000 Newbuild http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17669 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17669 Sat, 17 Dec 2022 12:38:12 +0000 freemp31 I have opted to mount them at ground level because my roof is E/W aligned, and the S end is shaded by trees, plus the fact that I have 3 hectares of land which is just grass.
However, to get sun for the maximum day length, the panels will need to be some 40M from the tank, which sounds like a hell of a lot of cold water needing to be circulated from the manifold before any heat gets to the coil.
A Laddomat (which I have on the accu's primary circuit from the gasification boiler) feels a bit like overkill - especially at their current price - anyone found a reliable solution to this problem?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17619 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17619 Mon, 24 Oct 2022 12:57:40 +0100 owlman If possible, I realise I would need a three-phase supply in order to get a boiler with sufficient output to feed a 2000l buffer tank. The beauty of the idea would be that everything else stays the same with only the heat source changing.
I wondered if anyone had attempted this?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17666 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17666 Wed, 14 Dec 2022 09:42:20 +0000 Swarm
I know about units like Zehnder filter box but am nervous about fitting them to an otherwise functioning MVHR unit. Cutting pipe work etc.

Has anyone else dealt with this problem? Are such units simple to fit?

I also wondered about buying some hepa filters designed for vacuums and sealing them inside the actual room outlets. If I remove the outlet there is a plastic plenum? box that could fit a filter and I could seal around it. I thought maybe that the cumulative area of these filters over all the house outlets could be similar to one large filter next to the main MVHR. With the bonus I wouldn't have to modify the main unit pipe work.

Finding a suitable size filter is challenging but I should be able to. Worth a go maybe?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17646 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17646 Mon, 21 Nov 2022 11:56:19 +0000 Victorianeco
Any recommendation on suppliers? I need one with easy fit pipework

Thanks]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17337 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17337 Mon, 27 Dec 2021 14:07:30 +0000 Buz
I’ve recently had a Cordivari Combi Eco 2 thermal store installed which is fed from a Charnwood Cove 2B wood burning back boiler stove and so far not impressed.
The problem is the store just isn’t getting up to more than 40 degrees (output quote from manufacturer as wood room 4.6 boiler 6.5, anthracite room 7.1 boiler 9.3) there is a Laddomat 21-60 three way valve which recirculates the boiler water until it reaches 53 or 63 degrees (depending on which thermostat valve is installed) and then opens to allow hot water to fill the tank but I can’t get the valve to open as temperature is too low. The boiler to tank pipes are 22mm and approx 8 metres and the heat dump radiator is fed in 28mm and approx 5 metres from boiler, rad is is per recommendation on data sheet.
Do you think the boiler is man enough to supply the tank volume and the issue is elsewhere or am not generating enough heat from boiler, at the moment only burning wood but delivery of anthracite coming soon for me to test. I have had it running for approx 5/6 hours a day and 3 days straight.

Thanks in advance for any wisdom shared :bigsmile:

Cheers
Pete]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17641 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17641 Sun, 13 Nov 2022 17:55:01 +0000 Erkindik
Has anyone installed a systems like this? What sort of performance have you seen?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17638 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17638 Thu, 10 Nov 2022 15:23:00 +0000 revor http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17616 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17616 Sat, 22 Oct 2022 11:43:57 +0100 HoveTom
I have a subfloor with wet ufh in place already and will be having engineered parquet laid over the top soon.

The blocks seem to come in 10mm, 15mm and around 20mm thicknesses. I’m wondering which thickness is best? I’m guessing the 20mm thick blocks take longer to heat up but perhaps retain their heat for longer so are better overall? No idea hence the post here.

My kitchen/diner has a new solid floor with around 150mm of insulation and around a 45mm screed layer ontop. The rest of the house has a suspended timber floor with around 75 mm of PIR insulation between the joists and then the ufh laid in about 20mm of a dry sand and cement mix on top. This is covered with Knauf Gifa board which is 18mm thick and has very good thermal conductivity (about 4 times that of a a chipboard subfloor).

I’m thinking the 10mm blocks may be just too thin (they have the same wooden wear layer as the 15mm blocks) and so not very strong and that the 20mm blocks are unnecessarily thick. So leaning towards the 15 mm block, does anyone have any experience, good or bad?

We like the 'tumbled' look which is when new blocks are thrashed around in a mixer with stones to knock the edges off them and make them look a little older. In order to survive this process most tumbled blocks are around 20mm thick. 15mm tumbled blocks can be bought but there is less choice.

Any experience appreciated.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17596 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17596 Fri, 07 Oct 2022 10:14:34 +0100 neelpeel The room is insulated, but I still think it must waste a great deal of heat, especially in the summer when the heating is switched off and only the hot water is left running.

The wasted heat I think comes from the need to heat a buffer tank. Is there a way to switch this feature off or bypass it completely? I know this would mean waiting for longer for the water to heat when having a shower, but I'm willing to live with that and use the kettle for most hot water needs.

The boiler is a 15 yr old Grant Vortex Outdoor Combi.

I had considered directly insulating the boiler, but I guess that could overheat the components and lead to speedy boiler death?!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17603 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17603 Thu, 13 Oct 2022 03:11:47 +0100 omehegan
Now I'm thinking about the future, and what I would replace this boiler with when it's time to get off gas completely. It's just an academic question at the moment, but I am wondering what others would suggest. The house doesn't have ducts, and adding them would be complex, so any kind of ducted central system is probably out. Mini-splits in each room would be feasible and may be the way to go, ideally if I can control them from a central point. But the hydronic heat is nice for comfort, and I prefer it to fans and hot air blowing around the place. However my impression is that air to water heat pumps struggle to match the efficiency and performance of air to air ones for home heating. I suppose the other upside to air to air is that they can provide cooling in all rooms as well, something that we don't have today... I also note that there are more exotic things, like the Tepeo ZEB boiler. Maybe something like that will be a better option.

Thanks in advance for any thoughts!]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17549 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17549 Thu, 25 Aug 2022 21:02:53 +0100 tony http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17527 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17527 Thu, 28 Jul 2022 12:21:33 +0100 tony
Bleed your radiators. Trapped air can make your radiators less efficient, so they'll be slower to heat up. If you feel confident doing it yourself,….

I disagree! The use of the term efficient winds me up again

I think that they might mean, ‘Trapped air can make your radiators deliver less energy’ which it could be a good thing as bills will be lower.

Bleeding the ‘air’ out will help them deliver more heat to the home and use more energy and cost more.

Again the opposite of what they were saying it would do (use less energy)]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17516 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17516 Fri, 15 Jul 2022 18:28:45 +0100 Swarm
I assume it should at least be able to cool one room for sleeping in and all hot air would just go up the vent and out through the mvhr without much issue, other than perhaps warming the incoming air slightly for the rest of the house.

None of my windows are suitable to vent out of, thanks to internal blinds needing to be closed and windows opening inwards. Plus it would be preferable not to let in warm air!

Is this worth considering or are there some gotchas I haven't thought of?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17509 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17509 Wed, 06 Jul 2022 23:37:15 +0100 Followthemoney
Not permitted to put solar thermal on roof or anywhere near house. Solar PV is only practical generation we can install in a field about 80m from the house.

We have 'twin phase' electricity supply (two single phase mains through two separate meters, two consumer units) use average 16kWh/day of electricity. In winter around 18L/day oil and in summer 7L/day on domestic hot water (300L cylinder) and keeping the under-floor slab ticking over.

A neighbour has 17kW PV (the max permitted 1ph grid tie) and in Nov / Dec / Jan it delivers average 10kWh/day. Not much, but enough to run the dishwasher and supplement the hot water. May / Jun / Jul / Aug it's 60 to 70+kWh/day.

My take-away from these figures is go large because PV is relatively inexpensive and aim to export nothing we don't have to. I think we might get permission to grid-tie 8kW to each incoming main, and this is about the max size of domestic 1ph inverters.

So, proposal is 24kW PV array, 3 x 8kW 1ph inverters, two of which hooked into our existing consumer units. 1500L accumulator tank fitted with 9x 2kW immersions. Set up the demand management to favour any domestic load, followed by the lower immersion in the domestic hot water tank. Any additional energy (in 2kW increments, as available) from the two grid-tied inverters to the accumulator, plus all the energy from the third inverter.

On average mid-winter day we should get a chunk of our domestic demand covered, plus most of our hot water. For the other 9 months, and particularly Apr to end Sept there should be 75 to 100kWh/day (on average) Knock 30kWh off for domestic use and hot water and that leaves 45 to 70kWh for the accumulator, saving maybe 4.5 to 7L of oil we'd burn otherwise. The 1500L accumulator should store around 70kWh if the mass of water is heated from 45C to 85C, then extracted to a heat exchanger on the central heating circuit.

No PV installer is much interested in this plan, too much plumbing and a bit left-field, but what does the community think?

P.S. I've considered batteries and calculated that they are no friend of the environment or my wallet, even with electricity at 35p/unit. One of the problems Is that we would need two batteries and charge controllers for each 'phase' of our supply, doubling the cost.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17486 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17486 Sat, 11 Jun 2022 12:03:05 +0100 RobWeir
First post - I'm a long time lurker, it's a great site but it's taken me 15 years to get around to finalising and commisioning my heating system..

I’d like some help please, selecting the right TMV and pump for mixing down the Central heating supply temperature - being taken from a 350litre tank (working partly as a buffer tank, partly thermal store). This is probably quite a simple problem for professionals and folk that have done it before, but I’m doing all this for the first time (I’ve split an old pub into two, so I’ve got a second more complex living unit to do after this one).

Should I use a TMV and Grundfoss pump (like a lot of UFH systems) – or a motorised valve (which must need a controller and add complexity and cost).

I’m struggling to ID a good value Pump/TMV array that will output 70-80 deg C water and accept 95 deg input. The standard UFH and DHW TMVs regulate to lower temperatures than I think I want…

This is for a Wood stove backboiler based heating system. I’m using a single vented 350 litre tank/thermal store for DHW and CH, fed directly from a woodstove/boiler, and indirectly by Solar (and possible in future by Heat pump – but I’ve no dedicated coil for that).

I’ve only got a single 15mm flow and return circuit feeding 3 rooms (plus a towel rail). 2 bedrooms with TRV and a living room which has thermostatic controller built into the fan convector.

I’d like the freedom to bring the tank up to its maximum safe working temperature (90-95 deg C say) so as to maximise the thermal heat storage capacity of the tank.

The Overtemp safety valve on the Woodburner is set to 95 degC. The cylinder manufacturer recommends a 90 deg max temp (‘to avoid boiling’), and my main open plan living room radiator (a DIMPLEX SmartRad fan convector) states max CH Feed temp should be 85 degC…

Please check out the attached diagram (cobbled together but quite representative).

MAIN QUESTION(s)...
Can you suggest a Thermostatic Mixer Valve that will provide adjustment between say 65 and 80 degC? Can you suggest a CH pump that is right sized for this size of job.
If I am sourcing separate Pump and TMV does the pump always go downstream of the TMV?

Controls: I wasn’t thinking of switching the pump on and off with a room thermostat, I was hoping I could use a basic timer with a simple on/off manual override. In this case I’d want the flow rate to throttle right back (to nearly zero?) when the TRVs were all closed off? Is there a smart pump that does that? If I need a bypass VV I’ve seen a suggestion (here) to bypass in a loop back into the supply line (wouldn't it be better if the bypass was fitted from the output of the pump back to it's input? That way it wouldn't stir the thermal store?).


GENERAL THINKING ALOUD…
There seem to be three good reasons for a Thermostatic Mixer Valve (or equivalent motorised VV) in the CH supply. 85 deg C is what Dimplex have specified as a max supply temp. Mixing down would improve or rather maintain stratification, and it should reduce any burn hazard for occupants. Note that all 3 of the room radiators in the house are Low Surface Temperature designs.

There is a good reason to allow quite a high CH supply temperature…I am using a fan convector in the main open plan kitchen/living area, as part of a ‘low thermal mass’ heating approach. This convector is oversized (maybe 5 times) by conventional standards. The intention is to be able to heat up the room so fast that the heating can be off when the room is not being used, or when the occupant is out of the house. The higher the feed temperature, the easier it is to make the occupant feel they have access to ‘instant heat’, and so can allow parts of their house to be cool when they are not in use.

I’m pretty sure 70 degC CH Flow temp would perform adequately as a maximum temp but I am truly lost looking to source the right pump and TMV on the web - there is so much choice and variation in cost.

I see lots of mass market DHW and UFH mixer valves that seem good value, but when I look for a TMV or a load unit spec’d to 65-80 deg C I cannot find them or the prices seem to be 3 times higher. Am I looking in the wrong places or at the wrong things? Should I be buying separate Valve and Pump components for best value/compactness?

Pump wise - I was considering a reconditioned Grundfoss pump (off of a well known auction site). The house has such a small system with TRVs on all the radiators that a small modulating pump is not needed to be working very hard so a pressure sensitive pump that modulates down to nearly nothing would be good.

EVEN MORE BACKSTORY
I’ve rebuilt a small listed pub in a Scottish village, splitting it into two housing units.

I’m commissioning the smallest 2 bed unit first. It is about 70 m2 with MVHR and a design heat load of under 3 kW. It has a single downstairs open plan living space, with two bedrooms and a bathroom upstairs. There are only 4 radiators on 15mm pipework in the house, all with TRVs.

There is a single vented thermal store (350 litres) for DHW and CH, which is directly heated from the Wood burner (through a load unit). The stove is supposed to output 2.3 kW to main living room and 6.1 kW to the water (but who knows). The stove has a thermostatically controlled damper on an external air intake.

There is a solar coil which I’ll probably have to hook into a wet solar thermal panel system for summer DHW. I’m really tight for space locating panels, otherwise I’d put in PV with an immersion heater for simplicity. I can’t use the roof because the building is listed, and I’ve very little unshaded yard space for PV panels so it has to be Solar Thermal, or maybe just use the Solar coil for a Heat pump option instead.

The bedrooms have small (Low Surface Temp) radiators and the main room has a fan convector unit (DIMPLEX ‘SmartRad’ SRX180EM). I am using a Fan convector so that heating can be switched off when house/rooms are unoccupied (because the convector can heat up air quickly when occupied).

Of course, the Convector gives me the option of using low grade heat when the store is nearly exhausted or to maintain a good COP if an air/water heat pump is added in future (I’d like to think in the long run we’ll most of us have access to a district heating scheme).

My initial building warrant was approved >15 years ago, utilising a small oil boiler. So I need to redo the SAP calcs and submit B. Warrant changes adapted to whatever is now allowed!

In winter, I’m expecting to light the fire (in the downstairs living space) each night. The intention is for there to be sufficient energy left in the store tank to have a shower and heat the living space for breakfast without relighting it, then go out to work leaving the heating off. Ideally there would be a smidgeon of heat left in the evening to take the edge off whilst the stove is lit!

My plumber is good, but hard to get hold so I’m making all the design decisions, buying the gear (possibly reconditioned Grundfos pumps) and mocking up the pipework …so he can make a neat compact job as fast as possible, when he gets a moment. We’ve got Solar, Wood Boiler and possibly a future Heat Pump CCT as well as DHW and CH… in quite a small airing cupboard space!!

When I’m happy with the small unit I’m doing similar but more interesting stuff in the adjacent 4 bed unit which is heated only with oversized convectors and uses a 1000m3 Thermal store.

Sorry to say so much – any comments on any aspects welcome 😊.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17491 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17491 Thu, 16 Jun 2022 22:54:09 +0100 1980scotland
Wondering if I can pick your brains on a fairly well worn subject.

I have a solid fuel Rayburn which I rarely use - boiler current removed and replaced with a heat brick. I use an ASHP for heating and hot water. With electric prices, have the feeling I should integrate by Rayburn boiler somehow. I have a sealed system, no thermal store - the ASHP heats UFH and DHW tank directly.

The floor height of the water tank is approx 1m below the Rayburn floor height. I am wondering about adding a buffer tank somewhere, and then linking that in to the existing system.

Thoughts appreciated. Since I have the Rayburn, the Rayburn boiler and the existing system - wondering if I can add a few system parts and do this integration.

Cheers]]>