PassivHaus Refurb

[Andy Simmonds]

As some may know AECB has been advising the TSB on its retrofit for the Future Competition. Some of the presentations AECB gave are here, and this link is direct to the presentation I did on our refurbishment project. The powerpoint slides are accompanied by audio commentary of the speakers. http://retrofitforthefuture.ning.com/video/andy-simmonds-case-study-in

My presentation is missing a slide which may be useful, here is the missing slide.

[Rob Rickey]

We have just found our house and I want to achieve the best performance possible. I am new to AECB and Passivhaus, but I will get the PHPP soon. Setting the target is important, so can you recap the current best practice thinking for refurb? We will be adding a first floor studio to the garage as well, which could be Carbonlite Gold as it will be mostly new build.

[Andy Simmonds]

See http://www.aecb.net/forum/index.php?topic=2134.0 (I HAVE CORRECTED THIS LINK)
re observations on Mechanical Ventilation and Heat Recovery (MVHR) relevant to this thread.
By the way (BTW) MVHR is now to be called Heat Recovery Ventilation (HRV) or as my children call it 'The Wind Machine' (TWM) - in order to lose the 'MECHANICAL'/'IRON LUNG' connotations that get some people so over excited....

[Andy Simmonds]

interview with Soeren Peper regarding following queries:

'Widespread concern in UK about health problems of poorly maintained MVHR
and tenant ability to understand/operate them.  Can you help with any studies
in Germany or elsewhere?  This is becoming a policy issue at the highest
level. It is vital we make "Comfort ventilation" a positive thing in the
UK.'


He said that this issue was heavily researched about ten, fifteen years
ago, and you will find a huge variety of - German - literature on this topic, by
Wolfgang Feist (still working at the IWU Institut Wohnen und Umwelt -
institute for living and environment) and Witta Ebel, as well as architect
Schulze Darup and Uwe Muenzenberg from AnBUS (Analyse und Bewertung von
UmweltSchadstoffen - Analysis and evaluation of pollutants).

These being the main documents:
- Wolfgang Feist, IWU 1994 Air quality in Passive Houses 'Luftqualitaet im
Passivhaus'
- CD by Schulze Darup ISBN 3-9808428-1-9
- Conference proceedings, 7th Passive House conference in Hamburg, page
191: Article from Uwe Muenzenberg: indoor air quality in Passive Houses
'Raumluftqualitaet in Passivhaeusern'.
- Passive House Institute: Protokollband Number 8 'Materialwahl, Oekologie
und Raumlufthygiene', 1997 = Volume 8 of Research group cost-efficient
Passive Houses: choice of materials, ecology and indoor air
quality/hygiene.

Key is that filters are regularly replaced. In the first Passive House,
this was done, and the ventilation ducts were examined after several
years: no dust, no mould, no humidity insided the ducts.
If there are concerns that users would not change the filters themselves,
then there should be a maintenance contract between the house owner and an
external company to ensure that the filters are changed on a regular
basis.
During construction, a proper site supervision is crucial so that the
ducts are clean at the time they are installed.

[Chris Herring]

And in discussion with Wolfgang Feist at the AECB conference this year, he said that the ducts are still very clean now 18 years on.

[Nick Grant]

Andy, what are we allowed to call MEV these days?

[David OLIVIER]

Is this renaming part of the UK tendency to re-shuffle the chairs or reorganise the company/govt. dept. and feel one is accomplishing something?!

The whole topic was studied in detail by the R-2000 Program in Canada which found that airtight houses with MVHR were healthier in some respects than conventional houses. Actually I awlays refer to them being draughtproof as that is a more attractive concept.

I can't really see much better acronyms than MVHR and MEV. Comfort ventilation sounds rather bland and wind machine might be misunderstood.

I hope the TSB projects will include a number with MEV, not just MVHR. On my calculations, MVHR appears to be a waste of money unless buildings can be made as tight as Andy's house, since MEV neutralises the background air infiltration throiugh cracks and gaps, whereas MVHR doesn't.

D.

[Nick Grant]

David

Your MEV v MVHR analysis was excellent and made me think re our own house should I ever get around to fine tuning.

Nick

[Dave Howorth]

Personally I think there are [at least] three problems with MVHR as an acronym:

(1)  I can never remember which way round the the V and H go; I always have to say the words in my head as I type it

(2)  If you go to google scholar and search for 'mechanical ventilation', all the hits are concerned with patients in intensive care. If you add 'house', it's all about patients who are in intensive care but have been taken home. In other words, it already means something different and it has negative connotations.

(3) It's a FLEA not a TLA ( a four-letter-extended-abbreviation rather than a three-letter-abbreviation ) and people like TLAs. The American HRV is more snappy

On a more serious topic, is there any HR when you do MEV? Is there a good review of the energy balance somewhere?

[Alan Clarke]

I hope the TSB projects will include a number with MEV, not just MVHR. On my calculations, MVHR appears to be a waste of money unless buildings can be made as tight as Andy's house, since MEV neutralises the background air infiltration throiugh cracks and gaps, whereas MVHR doesn't.

D.

Unfortunately with the TSB measures being rated for cost effectiveness in SAP, MEV won't feature as SAP assumes that MEV performs the same as natural ventilation but with additional electrical consumption.

Alan

[Andy Simmonds]

I have uploaded in the file' section a pdf showing Relative humidity levels and temperatures and gas consumption for the period nov 09 - end jan 2010.
see database entry at http://www.aecb.net/cbpd/viewProject.php?id=7#downloads

We are working on a lovely new 'front end' for the database and also will be using it to show the TSB Retrofit projects in the near future in conjunction TSB. Hence it will be come a fully searchable and good looking combined database for refurbished and new build low energy buildings.

[Andy Simmonds]

measuring 80% less gas and 45% less electricity compared to average for this house type, house age, occupancy, no. of bedrooms etc. assume average temp that our house is compared to (British gas statistics) is 17.8 degrees c as per BRE fact file etc - we run it at 21 degrees c. So 80% less gas in a cold winter AND higher than average temperatures. Looks like it works....current estimate of the project is that for conventional repair, renewal/improvement  and energy efficiency measures of the EXISTING element of the project (ie not the extension) we invested c. £35,000 in it for c. 90 sq. m of house. about £400/m2, so even with architect's margin of error  , a lot cheaper than demolition and rebuild.

22 march: I am generally bandying around a figure of £45,000 for a 'typical semi' of 90 sq. m to be on safe side - v. roughly £10k for insulating walls  - £10k for windows and doors, £5k for MVHR, the rest for roof and floors and airtightness, 9if roof is reroofed) and associated repair work that is prompted to by the measures. Rough and ready figures, and we are on a mission to see if we can make it ever cheaper !

We are also suggesting that rural, off the gas grid areas, on architecturally 'undistinguished' buildings, heated by electricity or oil etc are the most sensible place to start applying PH/Enerphit refurbs, as the PH type measures save most carbon and running costs in these situations. Learning from doing it anywhere at this stage of course is valid too, but the flip side of that is that a ph refurb in a town or city, or conservation area could become to be seen as too complicated and expensive, and needs to be balanaced out with elegant simple applications as suggested above. Mark Brinkley's blog on the subject of a RfF Ph project is an example of this.

[Peter Bayer]

Andy

Given that £45,000 equates to around 30% of the price of a semi ( £150,000 around here ) I think there is some way to go before passive house refurb is seen as affordable. The people who would benefit the most struggle to afford basic maintenance, at this level whole areas would be left out in the cold.
It might be an idea to define affordable, what percentage of house price would be acceptable to:-
a, House owner occupiers?
b, Grant providers?
c, Landlords?

Peter

[Andy Simmonds]

Peter,
If it turns out that taking into account all associated costs that it costs 'UK plc':
* £1,200 to deliver a Kw to a citizen using offshore oil,
*£11,200 for the same delivered kW from offshore wind (what is it for nuclear?!), and
*£1,300 per saved kW for energy efficiency measures applied to buildings via retrofit solutions , such as average of [enerphit in off gas grid rural areas and lesser measures + low carbon piped heat in urban areas] - then.....where should the UK invest first?

It suggests UK should invest in applying energy efficiency measures in buildings as closest cost per delivered KW to offshore oil - and also that equitable financial mechanisms should be supported to allow a) the investment to take place b) the return on investment to be fairly distributed to those affected by the works etc

sorry late at night (for me), but you see what I mean - this burden needn't / shouldn't be on the homeowner/tenant - as UK investment in this may one of the cheaper ways for the UK to save a tonne of carbon compared to the alternatives? We will need wind power etc etc, possibly we may need some nuclear (unclear yet - but the challenge is immense ), but least cost first surely - as in reality the all wind (renewables) vs all nuclear + ignoring vast potential of energy efficiency  may well be unaffordable for UK. Have the gov. done the research and sums. No.    That's why AECB are about to peer review its Less is More paper - energy after oil...

[Andy Simmonds]

Also - if you spend less on energy efficiency measures on homes, then all the savings are going to be taken up in increased comfort levels (temp.) rather than actual energy (fuel bill) and emissions savings. given post below - implying we shouldn't feel guilty about living in warmer houses (UK has coldest homes in europe?) then green deal levels of investment will result in warmer homes, but prob not lower bills or emissions.