It's just HRV "Heat Recovery Ventilation" or ERV "Energy Recovery Ventilation" (for those systems that also exchange humidity between the air streams. At least, that's what it's called over here - the "M" bit is a given :)

As for your price quotes, that's quite insane to be quoted £10k - I assume that must also include a heat pump? Even so, that's more than we paid for a full GSHP installation here in Montreal.

Posted By: James Norton(ie the tins says it recovers more heat than it loses and its not too noisy and doesn't breakdown much..)

It can't recover more heat than it loses - did you mean recover more heat than is *uses*? They all should do that - but *only* if you have an airtight house in the first place. If you don't, then it's a waste of time/money.

Over here the systems are available in big box hardware stores for around Can$700 or less - but not including the ducting (not that that is expensive). I have no idea how much an HVAC contractor charges to install - we had ours installed in the new house as part of the overall HVAC installations and it wasn't a separate line item as HRV systems are mandated by code over here anyway.

As for noise, ours isn't noisy - but it's in the mechanical room of the basement - the air flow is silent as far as I can hear. As for reliability, it's just a synchronous AC motor so should last for as long as the bearings last.

Paul in Montreal.

Just been,today, for my free course for installers with a Dutch company with a third of the market over there. I hasten to add that the UK headquarters are in Burton on Trent! The HRU 4 MVHR for a house of up to 175 M2 is just under £1000 for hard wired controls and £1100 approx for the remote control version. Amateur installation would appear to be simple and straightforward, especially for a newbuild with appropiate planning from an early stage. Apparently I-beams can be a problem as one is only allowed to make a single hole of 125mm diameter; the makers recommend rigid ducts of 150mm diameter or flat 240 x 60 neither of which are allowed.
This unit is DC, EC motors with a specific fan power of 0.5 w/l/sec, i.e. scores very high on SAP Q. Inlet ducts to habitable rooms are recommended to be sited near windows; apprently grilles near corners often have wardrobes etc placed in front of them

PS

Has any one heard anything about the 'PAUL' units supplied by GBS...? I suspect top notch performance but big price tag...?

J

Type 2

Thanks for that Ed, so w/ regard to the heat exchanger, there all pretty much of a muchness?

also

Posted By: Ed DaviesIf the ground around the ducting is to ever be warmed then you need to run air through the duct which is warmer than the ground. This runs the risk of condensation and hence mould.

was thinking the other way round ie the warming up sub zero winter incoming air taking advantage of warmer winter ground temperature so the heat exchange doesn't have to do as much:

Posted By: James Norton Good to know that my suspicions about £ insanity were correct. Have looked into it a bit more since posting I'm seeing common things in nearly all from the sub £1k to the '£insane'.

Not just £, Euro too. I was quoted around 2600 Euro for units from Germany (Paul and also Innoair) both certified by the PHI. The more reasonably priced (sub 2000 Euros) were from Ubbink, Helios and Ventaxia.

What are posi-joists? Why not just use engineered floor trusses? They have plenty of space to run pipes, ducts, wires and what have you. Plus they use less material then either regular joists or I-joists.

Paul in Montreal.

Thanks James - they look like engineered trusses buy use metal webs between the top and bottom chords rather than wood. Lots of space for ducts and the like though!

Paul in Montreal.

Are posi-joists much more expensive than a solid wood joist sized to take the same loading?
I am interested in getting more headroom on the ground floor by using more joists of a smaller size and I like the idea of being able to run services through the Posi-Joists.
Can they be cut to length or do you need to get them manufactured the length you want? (uneven stone walls)

I fitted ours to an existing house (with first floor completely in bits at the time tho').
We have a Stork MHVR 90 (Greenwood/Starkey Systems in the UK) - DC motors, pullout filters, infinitely variable speed as DC but with three basic settings - each programmable as to extract and supply speeds etc, timer boost pullcords next to the showers. MHVR90 is dutch I think, seems well made compared to some of the plastic stuff I've seen at shows.
Our original quote did have two of the main units, but they had one ex-display, removed from a show house, so we got just the one unit 'cheap', and it's perfectly fine, apart from some plaster spatters on the case. Two grand, for everything inc about 12 extract/supply terminals. I'm guessing installation would be a lot of £££, but it's not rocket science, as long as you have a design and plan to work to.
I'd recommend the spiral wound rigid metal ducting - cut with an angle grinder, and all 90 degree/tee/jointing pieces have a rubber seal, so in theory you don't need duct tape (actually ally foil tape is best). Flexi-duct is supposedly noisier, can reduce airflow a bit due to lack of a smooth bore, plus if you are entertaining the possibility of having mice at some point...
Ours is all rigid, then a foot or so of flexi to each ceiling outlet. Main in/out from outside to the main unit is flexi insulated with foil and rockwool - tricky to work with as it's so bulky, but stops condensation in the unheated loft void area.
If I did it again, I'd do the underground air inlet - 20 degC air in summer and winter for free is too good to pass up on, and could be done with any system, provided underground access is feasible from the main unit.
From a personal K.I.S.S viewpoint, I wouldn't get a unit with the rotating heat exchanger, no matter how efficient they claim it is - just looks a bit Heath Robinson, plus there's an extra motor and a drivebelt to go wrong.
Overall, highly recommended, and there's not much I can say that about - no bathroom mould in existing mouldy bathroom at all in 2+ years, no open windows needed unless it's august and 30 degrees outside, no winter stuffiness (2 of us have asthma), no draughts, it's quiet (can *just* hear it in the bedroom at night, like a gentle breeze outside, unless it's on boost), and it sucks well on boost - bathroom mirror can stay clear even when the shower door is opened.
Of the two you've pictured, ours is a 90 degree tilted version of type 1.

With regard to "heat exchangers are all basically the same"; I remember a post by Paul in Montreal about quoted surface areas of heat exchangers. Most manufacturers/ sales teams can't, or won't, supply this information. Paul in M gave examples that ranged from 17 to 50+ m2 surface area. waiting to hear from Itho about the surface area of the HRU4; when on the installation course initial indications that area is in the higher end of the range above.

James, yes Appendix Q of SAP; I have yet to do my own installation and then my Daughter's. With the other aspects of my extensive refurb and 'new' garden, I will be overwhelmed till at least Summer 2010!

Paul(T),

So basically there's a fan in each if the little black and red boxes, which each serve one or two rooms? Low/mid/high price...?

J

Just to ressurrect an old thread, has anyone come across the Vortice Prometoe? Looks like a nice unit, well designed, wireless remote and apparently efficient - at an apparently good price..

http://www.vortice.ltd.uk/product.aspx?id=1045