Deep retrofit – the big prize?

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?

In the first part of this article we looked at the damage fuel poverty and cold homes do to occupants’ health, and found good evidence that when these twin evils were tackled, occupants could enjoy measurable improvements in their health. Encouragingly, some local health bodies are recognising this and investing in home retrofit to help improve people’s health.

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Fixing fuel poverty – is there a healthier way?

Fuel poverty causes misery and ill-health – and alleviating fuel poverty by retrofitting homes could potentially offer valuable savings to the health services. However, different approaches to retrofit are likely to have different impacts on health.

The first in this two-part series, published in Green Building in December 2014, looks at how cold, damp homes can harm people’s heath, and at the evidence to date that retrofit can improve matters.  It also explores some pioneering efforts by concerned health organisations to tackle the ill health of their vulnerable patients where it starts – by fixing their cold homes.

The second part, due to be published in Spring 2015, will look a little more closely at different retrofit strategies, and the risks and benefits to occupants – and to the buildings themselves.

PDF download: Fuel poverty and health – Part 1

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Overheating – how can we avoid it?

Jump straight to article in html Overheating – how can we avoid it?

There is a lot of concern that modern, airtight, well-insulated buildings might be more prone to overheating than older, leakier ones. However, the worst-offending buildings for overheating (and there are some shockers) are as often old as they are new. Overheating buildings just tend to be all-round bad buildings: often cold in winter, as well as hot in summer.

It looks as though buildings with too little insulation, too much glazing, not enough shading, and inadequate provision for purge ventilation are at risk of overheating – as are buildings with badly designed and inadequately insulated heating/hot water/community heat systems. Extravagant use of glazing, in particular, seems to have a great deal to answer for.

But there are ways round these dangers, and if designers take all these factors into account, and also use thermal mass carefully (its no good of it sits in the sun all day!)  overheating ought to be less of an issue. However, its important not to skimp on the calculations and modelling during the design process – and equally important not to lose sight of common sense.

Article first published in Green Building, Spring 2014. Apologies for the absence of references – these will be added when I work out the best way to include them.

Overheating: how can we avoid it?

“Everybody loves the summer time”, as Carole King once sang: everybody that is, except those who are separated from their sweethearts – and those sweltering in stifling buildings that they just can’t get cool.

At its worst, overheating can be a serious – even fatal – health issue, with the very elderly, and babies and small children most vulnerable… read more

 

 

Overheating – how can we avoid it? – article from Green Building

This article originally appeared in Green Building, Spring 2014

“Everybody loves the summer time”, as Carole King once sang: everybody that is, except those who are separated from their sweethearts – and those sweltering in stifling buildings that they just can’t get cool.

At its worst, overheating can be a serious – even fatal – health issue, with the very elderly, and babies and small children most vulnerable, and heart attack, stroke, and sudden infant death all possible consequences. But much more commonly it is a discomfort issue, which can affect the usability of buildings, and/or drive people to deploy energy-consuming measures such as artificial cooling.

A building that cannot be cooled down to a comfortable temperature whatever you do is obviously overheating. One that cannot be cooled in a secure and comfortable way (eg, can only be cooled via opening window onto a busy road, or by leaving patio doors open at night), overheats so far as the occupants are concerned. Both are a failure on the part of the design and construction team.

How hot is too hot? The occupant has the last word on this, but designers do need guidance on what ‘most occupants’ can cope with:

As the National Housebuilding Council reports, work by CIBSE and Arup suggests that most people begin to feel ‘warm’ at 25ºC and ‘hot’ at 28ºC. At 35ºC “there is a significant danger of heat stress.” Heat at night bad enough to interfere with sleep seems to compound the danger to health.

In practice, comfort also depends quite a lot on humidity (which determines how readily people can keep themselves cool via sweating) and air movement (ditto) .

In general, it ought to be possible to avoid overheating without sacrificing winter time comfort and energy efficiency. Despite a warming climate we’re still going to want houses (in the UK) warmer inside than out, most of the year. Continue reading

Can Passivhaus teach the policymakers to love the occupant?

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