Environment, energy, sustainable building
The team behind a series of passive house schools in Wolverhampton have used the lessons learned from in-depth monitoring of the first two buildings to make the third even better — and cheaper to build. Oct 2015
For the builder and his client, aiming for the passive house standard was just one part of an environmentally conscious approach that put natural, healthy materials to the fore.
The style of the house inside and out is what the owner calls ‘modern organic’ – white paint and render, and lots of natural wood. The carpentry is beautifully finished, with charming bespoke touches. Not everyone expects a passive house to be like this…Nov 2015
Natural ventilation often fails – but what is the evidence that mechanical ventilation succeeds? – Investigation for Passive House Plus
There have been a number of studies showing that natural ventilation, dependent as it is on random gaps in the building fabric and the vagaries of wind and weather, is not a reliable source of fresh indoor air. (see here for my article on this)
In theory, mechanical ventilation is under more control, and should work more reliably. But does the evidence bear this out? Does mechanical ventilation deliver good air quality in practice?
I looked into the research to find out whether MVHR, in particular, lived up to the ideal. Continue reading “A look at the evidence on mechanical ventilation”
While there are well-established technologies to produce electricity without fossil fuels, decarbonisation of heat is struggling to get under way. Recommended strategies include expansion of low carbon networked heat and possibly the decarbonisation of gas – though these are still only happening at a scale (and with dubious carbon credentials, see PH+ Iss 15 – district heating). However, the commonest proposed means for decarbonising heat is via electrification.
Electrification of heat raises a number of questions about the ability of our power systems to produce enough low carbon electricity and their capacity to transmit it. But it also represents something of a u-turn in building services design. Continue reading “Electric Heating – time to come in from the cold?”
Simple home energy efficiency improvements (such as new boilers, cavity wall insulation etc) can bring valuable comfort and health benefits to the occupants of inefficient homes – especially those in fuel poverty – as the last article revealed (see here). However, energy, carbon and bill savings tend to be modest, rarely topping 15% or 20% – and sometimes energy use actually increases!
If housing is to contribute its share of the 80% cuts in carbon emissions this country is committed to, in order to play is part in tackling climate change, retrofits will need to go deeper – a lot deeper. But will occupants benefit from the extra work? And is it affordable? Continue reading “Deep retrofit – the big prize?”
Passivhaus is no longer just the preserve of the self-builder: more and more large Passivhaus schemes are being announced. These include both non-domestic buildings, for example in schools and universities, and multi-housing schemes, generally in the social rented sector, though sometimes with a portion for private sale.
In this article for Passive House Plus magazine I looked at some of the economies of scale available on larger Passivhaus projects, and some of the obstacles that larger schemes may run into. Also, following from my previous article on the cost of Passivhaus, I looked a bit further into the economics of Passivhaus from the point of view of developers and owners – in both the domestic and the non-domestic sectors.
Read the article in pdf here: Passive House goes large
My thanks to Passive House Plus for the use of this document.
Passivhaus (Passive House) is often thought of as being “too expensive” for the mainstream. There are some designers and developers however who are managing to shave the capital cost premium down to just a few per cent – or even zero.
In researching this article for Passive House Plus I learned that the extra costs, where they are incurred, seem to derive from two main sources:
The extra costs are mainly up-front; looked at over the building’s first decades of lifetime, running cost savings – including maintenance, and even cost associated with tenant dissatisfaction – start to pay back the initial investment. Continue reading “The cost of building passive”
This is by way of an open letter to DCLG – which I sent as a covering letter to my response to (questions 1&2 of) the allowable solutions consultation – see previous blog
“I believe the whole idea of (1) “zero carbon” and (2) defining this or any standard not by how well the subject of the standard performs, but how many other people can be bribed to perform well on its behalf, is dreadfully misguided. Continue reading “Allowable solutions – who are they trying to kid?”
Ventilation was much in my mind as I dipped in and out of conversations and seminars at Ecobuild this week. And I began to notice a disturbing tendency for airtightness measures and ventilation to be discussed quite separately, with the costs and benefits of each addressed almost as though the two were unrelated.
Again and again, ventilation appeared to be an afterthought, or a problem, instead of an integral part of the assessment of building performance. Several people also lamented that “well, you can get draft proofing done on a Green Deal, but ventilation doesn’t meet the golden rule, so who will pay for it? – it can’t be funded”. And alarmingly, this dangerous split seems to be reflected in the very structure of the Green Deal.[1]
This strikes me as rather like saying “you can get this operation that you need, but there is no money to sew you up afterwards”.
Ventilation seemed almost to be resented, an ‘obstacle’ in the way of deeper carbon cuts, limiting what could be achieved. All that fresh air spoils the building performance, it seems.
This put me in mind of a similar flavour you find in discussions about ‘comfort taking’. Once again, the pesky needs of the occupants are getting in the way of the true goal of carbon cutting. Thus in its Green Deal Impact Assessment DECC complained that “comfort taking” leads to “underachievement in real-world energy savings”.[2] Is it really an “underachievement” to make someone’s house more comfortable?
In both these instances, there is a not-so-hidden subtext that the base animal needs of building occupants are a real hindrance to the low-energy, zero carbon perfection we are seeking. And in a way, you can see how if your job is to achieve these goals, a building with no occupiers would solve a lot of your problems.
So it might be unexpected in a way, that it takes Passivhaus, possibly the most shamelessly geeky and science-based standard of them all, to be the one that not only embraces the occupant, but actually starts from the occupant perspective. My understanding of Passivhaus design is it is built from the premise that occupants want comfortable, healthy buildings that are cheap to run. And yet, somehow, it looks as though Passivhaus manages to deliver the lowest energy and (I think you could easily argue) lowest emissions buildings of the lot of them.
Which is why (or at least one of the reasons why), as I remarked on Twitter this morning, I found that Passivhaus crept into my mind quite often, when I was pondering my uneasiness with what was being said outside the Passivhaus sessions. I think the Passivhaus lot are on to something.
[1] I was told that for post 1919 buildings there is not anything in the Green Deal that requires the advisors to assess ventilation, even when they recommend draftproofing. There are especially serious concerns about the mass-scale installation of solid wall insulation, where the installer alone is responsible for the ventilation strategy, with no back-stop liability resting with a Green Deal provider. This is an issue that needs more than a blog to tackle – hopefully I will get the chance to come back to this soon.
[2] DECC June 2012 Green Deal Impact Assessment