Apart from the assessment costs?

Possibly.

Its one thing for someone to do years of research, possibly after a background in the industry etc etc, to design to a standard and only very selectively depart from it for sound reasons and then use the money you saved not paying for a certificate on more improvements, or to phase the improvements so that you could theoretically meet a standard when funds are available.

However its quite another for an enthusiast to hang around on forums for a while and watch every episode of grand designs then give it his best shot and then claim he's built an eco house every bit as good as the above...
J

You have to start with a design based on something.

Not every house or building can be personally designed by a specialist, so standards that have been developed by comparing post completion testing and are progressivvely improved by post completion test are an essential tool in the kit.

J

Posted By: sinnerboy"If it acts like a passiv haus - it is a passiv haus"

unless you design it like a passivhaus its not very likely to act like one...

J

Remember there's other, non-Passivhaus ways to achieve the same, or better results. Passivhaus/CSH/mainstream housing-future policy is a simple (though rigorously challenging), starter-approach that works.

It's major shortcoming is that it takes its solar heat in through windows and stores it in the heavyweight interior elements that the sun rays fall on. A little while later, that stored heat comes out of storage into the room. the way it went in. Doing it that way puts a low limit on the total amount of heat that can be stored, the rate at which it can be absorbed when the sun's on it, and the useful duration of the storage.

Regardless of the mass/thickness of the heavyweight interior, when heat-in is to the same (room) face as heat-out, only about the first 100mm of its thickness is really useful. So e.g. 215 of dense blockwork gives little advantage over 100, in either quantity of heat storeable, or in duration of storage; screed directly on conc slab over insulation gives little advantage over 75-100 screed on insulation over slab. And the duration of storage is only about 1.5 days, 2.5 maybe - not enough to bridge over many a sunless spell in the heating season. The lowish rate at which the heavy surfaces can absorb peak solar input, when the sun's really belting, creates risk of overheating.

Put all that together, and this Passivhaus/CSH/mainstream housing-future policy approach is in effect a fine balancing act, in which risk of overheating puts a low limit on maximising the amount of window area, hence on the absolute amount of (and %age of available) solar heat that can be collected and stored, and the duration of same, hence the fanatical concentration on heat-loss reduction, because so little stored heat is practicably available.

What must be the next step, after this Passivhaus/CSH/mainstream housing-future policy starter-approach, is ways to greatly increase glass area hence amount of (or %age of available) solar heat captured, ways to semi-passively take it away to storage at a much higher rate, and ways to input it into the back-face of the massive storage elements, so that the heat can work its way through to the room-face in one, non-reversing direction. Then there's no particular limit to the amount of heat that can be stored, nor to its duration, by adding more mass/thickness to the heavy storage elements.

With that, we can relax quite a bit about fanatical heat-loss reduction, can afford bigger windows, not necessarily all south-facing, and generally be a lot less Germanically anal about everything.

Mark, I've noticed that you maybe feel I'm competing, challenging or even discrediting you and/or Passivhaus. Far from it - I have very great respect for your expertise, for your willingness to spread what you know, and for the Passivhaus system, which I quite agree with you is the most reliable, intelligently developed and useable system around. But it's unwise to think that Passivhaus is the endpoint, whether it evolves, or is superseded. It's not an article of faith. From your strong, experienced position, you can afford to actually engage with the detail of what I say, instead of 'with all due respect ... yet to be demonstrated ... etc' which just seems like trying to stop me rocking an unsure boat. Several valid points there, as I see it, but which I'm not rigidly wedded to, and would greatly appreciate your detailed insight on.

Is this the difference between following the spirit and the letter of the law?

Thanks Mark.
I agree Passivhaus works, reliably, and there's no point in trying to improve on what Passivhaus achieves - once that standard of thermal performance/minimal fuel use is 'in the bag' then the focus should shift to the other priorities that you list.
The point I was making is that achieving that performance the Passivhaus way is hard graft, and I'm looking at more relaxed and generous ways of doing it. And long-term robust, too.
There's much talk of the fanatical standard of workmanship that is necessary for succesful Passivhaus, and is that do-able in Britain?
A bit of talk too of the discipline in use that the occupants need, otherwise windows get left open etc - all the makings of another popular-press scandal with families claiming they had to go out and buy fan heaters, and what it cost to run them.
What works in Germany/Austria may not work with the lumpen British public and builder/tradesman.
So how to make the requirements for detailing and workmanship a lot more relaxed, and performance in-use a lot more tolerant?
Inter-seasonal heat storage is the holy grail - once up and running, makes construction and use very easy and relaxed - the opposite of the tightly-sealed, minimal-surfaced, small-windowed present/forthcoming state-of-art. But inter-seasonal's not here yet.
Meanwhile, there's much scope to improve on the quantity of solar heat captured and usefully stored, and the duration of that storage, whilst avoiding overheating, by the means I outlined.
If someone asked 'how's it done?' rather than dismissing the possiblity, I might divulge ...

Tom,
If there was an easier way, and I was aware of it, I'd be using it - believe me. To be honest I don't think that PH is overly "hard", the biggest restriction at this time is the availability of suitable technology (door, windows, MVHR) that also satisfies other UK requirements (SBD, access etc.) [I say this from my experience working on a 25 unit PH scheme.]

Skills can be learned. There is a learning curve (that we would all have to go through) but this is not rocket science it is skill and care. Skill and care that we should already be applying - if we did the buildings we build would perform as we'd expect. (See above for definition of "performance.")

Occupants - again the statistical mean is important, some consume more others less. This is not about a draconian requirements then ALL shall live this way or that, but rather a sensible understanding that is based upon appreciating how occupants and buildings behave/interact. It's true that at this stage, before any good UK based POE, there is no guarantee that occupancy and building performance will agree with that of Germany, but after the EST studies (on the scheme that I'm working on) we will hopefully have a much better appreciation of how PH really integrates with the UK climates and occupants.

Mark

Tony - has your question been answered i.e. whats "behind" your question ?

"Passiv House standard" is the term I hear most used

Lars here http://www.scanhome.ie/ has been doing it for years .
He seems in no hurry to obtain PHI certification

And you should hear him talk about BER ( EPC ) certs

http://constructireland.ie/Vol-4-Issue-2/Articles/Passive-Housing/Are-energy-ratings-letting-down-passive-houses.html

see also:

http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=4618

J

Thanks for the FAQ link,

....its two units... and I was hoping for a trade discount...



J

Hi James Norton

Can you explain a bit more about the "1% off your rate" if you build to a certain standard? Is this your mortgage rate?

Posted By: Viking HouseIs this your mortgage rate?

Yup.

J