Monday, 8 May 2017

Could Passivhaus be cheaper?

Passivhaus, Herefordshire, 2016 
I don't just mean cheaper than it is now, but could Passive House be cheaper than a regular building. And I don't mean cheaper in the long term, but cheaper to build.

Low energy buildings, Pennyland, 1979
When we were building, we found in most cases the extra demands of passive house provided extra opportunities for builders and contractors to charge us more money. I think this was partly our fault for not finding people who were interested in changing the way they work, so rather than seeing our house as an opportunity to learn how to build better houses in the future, they saw it as a diversion from their usual practice. Where we did work with people who were used to working to rigorous energy specifications, I got a strong sense that they were able to charge more because they thought nobody else could do what they were doing, or because they were aiming for rich customers who just judged value by the price tag.

The theory behind Passivhaus is that increasing insulation means massively reducing the heating system, so extra costs insulating are balanced by lower costs installing a heating system. Since Passivhaus also required a ventilation system, and rather than removing the heating system it just scales it down, this seems like a challenge. The cost of extra insulation, structural changes to accommodate and support the insulation, airtightness barriers, increased window specs and ventilation system all need to add up to less than a fraction of the heating system. 
State of the art building, Lavenham Wool Hall, UK, 1464 

According to this report from the Passive House Trust, sponsored be AECOM, passive houses cost 3-8% more in Germany, where many are built to the standard. In the UK they typically cost 15-20% extra, although the extra costs are less for large projects, terraces, north-south oriented buildings, and projects where the design can change after tender.

But some people are saying that Passivhaus can, and will cost no more, for example Passivehouse Plus in Ireland give the builder's view on why passive house doesn't cost extra.

Low cost, zero maintenance house, Japan
Twentieth century
And there is a best practices document developed in collaboration with EEBA, and Proud Green Building that asks this question: Can you build a high performance home without additional cost?

And they answer: YES!
Bird Table, Huddersfield,
Turn of millenium

You can Download your copy today! Which will tell you about putting a value on high performance, how to shift costs where they matter most, opportunities in green remodeling, builders' perspectives on achieving high performance, high performance home ratings and certifications, case studies and financial considerations.