Saturday, February 10, 2007

Are Passive Houses the answer?

Tomorrow I am off on a Passive House (PassivHaus) study tour. I take an evening flight to Hanover and join seventy others at the Loccumer Hof Hotel for a day of lectures on Monday followed by a full day’s itinerary visiting three PassivHaus sites. Sandwiched between this is a gala evening meal at Hanover City Hall for which they have thoughtfully emailed us the menu. It looks to consist of about half the annual produce of Lower Saxony and I don’t anticipate many of the guests will be clubbing into the small hours after that lot.

For those of you who know little or nothing about Passive Houses or, more specifically, the PassivHaus standard, I can’t do better than to suggest you mug up at the relevant Wikipedia page.

The Passive House concept is beginning to get wide coverage in the UK media. It’s seen as the most advanced example of low energy housing anywhere on the planet and over 6,000 have been completed to date, mostly in Germany and Austria. In the UK, the BRE have taken it under their wing and it is they who are organising this study tour. The question we will no doubt all be asking is: “Is this the future of low carbon housebuilding?”

Whilst there are lots of plus points, there are also serious doubts in my mind about whether the PassivHaus standard is the perfect solution. In particular, what irks me most is that it sells itself as a performance standard – it is quite specific about just how much energy can be consumed per square metre of floor area — but it also adds several other stipulations about what you can and can’t include in a passive house. For instance, you must have mechanical ventilation with heat recovery, whether you want it or not, and you must have windows with ultra-low U values. Why is it so prescriptive about these items? Are they saying you can’t meet the performance standard without these features? Or is there some other reason for including them?

They say that passive houses can be either masonry or timber frame? But German timber frame is very different to British timber frame: is our local version of timber frame suitable or does it need more thermal mass? What about using other build systems like SIPS or ICFs?

There are also lots of issues to discuss like costs and transferability to other nations? As discussed on the blog recently, the UK has the smallest homes in Europe. It’s harder to lose 300mm of wall insulation in a rabbit hutch. Does it make sense to do so? And does the standard restrict house design to the rectangular box? Or can it be adapted to the more varied UK styles?

Another issue is the requirement for triple glazing: is the extra expense, not to mention the embodied energy used in manufacture, ever justifiable in the British climate? In fact, I hope the whole house embodied energy argument gets aired. It’s hardly worth reducing the annual carbon emissions from 5 tonnes to 2 tonnes if it’s going to take an extra 60 tonnes of carbon to manufacture and build. Whether it does or doesn’t, I have no idea. But it’s the time and the place to speculate about these issues and I’ll be posting my answers when I get back mid week.



Anonymous jeff Kraft said...

Check out this

2:09 pm  
Anonymous adet said...

new things and new experiences visiting this blog see mya blog jaket kulit asli.. I really like the articles and posts written on this blog thanks admin

7:46 pm  
Blogger Unknown said...

we can no longer deny each blog provide useful news and useful for all who visit. jaket kulit pria visit back LOL

5:58 pm  
Blogger marko said...

Subcontractors are the individuals who perform obligations and commitments for a principle contractual worker. Individuals in the mining business are frequently under those terms of work. auto title loans chicago

6:39 pm  
Blogger marko said...

Take in more about the endorsement equation and get the help you have to apply and meet all requirements for advance alteration by requesting and downloading the top of the line handbook for mortgage holders, The Complete Loan Modification Guide. Cash Advance Chicago

6:45 pm  
Blogger marko said...

With the development of the money related market, more players joined the market and these incorporated the non-managing an account budgetary foundations. These moneylenders had less standards set up, which guaranteed that people with lower financial assessments could get to individual credits. Payday Loans

3:02 pm  

Post a Comment

<< Home