Archive keeps its cool the Passivhaus way

Hereford archive chooses passive preservation

Hereford County Archive

Safeguarding historic documents and other artefacts requires super-stable environmental conditions. This has usually been achieved by using masses of expensive and energy-hogging heating and cooling plant, but a new approach for Herefordshire Council used the passive house approach to conserve energy, money — and the county’s precious historical archives. Nov 2015


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Passive school learning refines the design

Building a better passive school

Wilkinson School, Wolverhampton

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


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Electric Heating – time to come in from the cold?

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

District Heating – does it work with Passivhaus?

Cost effective district heating schemes need a nice dense energy demand. They also involve a lot of circulating hot water, which with the best will in the world, is going to involve continuous heat loss. Highly-insulated low energy buildings need very little heat – and in the summer, heat gains can be a positive menace.

So can the two work together? I explored the question a bit in this article for Passive House Plus – downloadable here as a pdf.

District Heating – does it work in Passivhaus?

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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Why I think retrofit needs to move off energy bills and on to general taxation

Like many others, I am horrified that the government has scaled back aspects of the Energy Company Obligation mid-programme. You can read about some of the immediate, alarming consequences of this in a report from Inside Housing here.

However, as I’ve said before, it seems to me that long-term  it makes little sense to restrict the national retrofit programme to what can be funded via a charge on energy bills. In summary, this is why:

  • Retrofit is about more than energy bills, it’s about health, education, social welfare and common decency. And about energy security and cutting emissions.
  • Because of the state of our housing and therefore, the scale of the need, a high spend is required.
  • Because of the scale and the range of the benefits, a major retrofit programme would bring tangible revenue savings to a range of bodies such as those tasked with improving economic, health, social welfare and educational outcomes, and delivering on our carbon targets.
  • Paying for retrofit through energy bills is regressive, hitting the poorest proportionally hardest, even at current spending levels.
  • The scale of the spending needs to expand many-fold. This would ramp up the regressiveness. In effect, every household, including the poorest,  would be paying a substantial chunk of the costs for NHS, social welfare etc via their energy bills. This is not only likely to be politically untenable, it also undermines the accepted approach to progressive taxation in this country.
  • The creation of a third party obligation, ‘leaving it to the market’ to decide what to deliver on the basis of a very simplified understanding of costs and benefits, cuts informed stakeholders out of the equation. It excludes them from them any meaningful say over priorities, responsiveness to changing needs, and quality of interventions.
  • It also ignores the ‘beneficiary pays’ principle: health, education and welfare budgets would all benefit considerably, on the back of bill payers.

*The ECO recognises only two parameters of benefit, presumed carbon savings (calculated via RdSAP), and “affordability” again, calculated via RdSAP.


Allowable solutions – who are they trying to kid?

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.

If you want to reduce the carbon emissions from new homes, then reduce the carbon emissions from new homes. Don’t reduce them some of the way to your target, then faff around erecting huge, complicated structures to reduce emissions from sectors other than new homes, and then pretend to yourselves and the world that somehow the new homes are low or “zero” carbon. Manifestly, they are not. What a colossal waste of effort!

If it isn’t possible, practicable, or affordable to make a new home zero carbon on-site (and it almost certainly isn’t) then for heavens’ sake don’t carry on pretending to yourselves or anyone else that it is. As you have found, the pretence requires a positively rococo structure of pretend emissions savings – your “allowable solutions” —  cumbersome, inconsistent, full of internal contradictions, and beset with potential loopholes.

And worse, what a colossal diversion of yours and the industry’s precious time and energy. All this effort going into refining the way you will trick out this delusion with regulations, price caps, verification procedures etc etc, when:

a)     the net impact on carbon emissions overall will be minimal (how can you ever know an action is truly additional, especially if people are competing for the cheapest actions – which, naturally, would be the ones most likely to happen anyway), and;

b)     you are incurring a huge opportunity cost in terms of effort, time, expense, and individual and corporate head-space – meaning the impact on emissions from new homes will probably be to INCREASE them relative to what they could have been, had you and your predecessors focused on reducing home energy in the first place.

Although mass housebuilders are notoriously uninterested in producing a high-quality product, seeing as they can sell what they produce anyway, given the housing shortage prevailing in this country,  some landlords/developers are now starting to take an interest in delivering really high quality homes. A significant number in the ‘affordable’ and social rented sectors, and now some building speculatively for the private market, are building or actively planning to build to the Passivhaus standard (the low energy standard I happen to know about). They are opting to build to truly low energy standards not because of any leadership from DCLG, but because they think it’s a good idea for users/purchasers, and it is possible to make it stack up financially, especially after the first one or two builds have been completed.

They don’t have any special trick, other than the right attitude. If they can make it work financially, then so can the big housebuilders. Perhaps the big housebuilders don’t want to change their ways, perhaps because their business model is based on shoddy workmanship. But the Zero Carbon Hub has told us this has to change anyway, to reduce the performance gap.

If the big firms adopted very low energy design, the marginal cost would fall considerably, as components would drop in price. And of course if all housebuilders were under the same obligation, then there would be no competitive disadvantage. (Your impact assessment cites a theoretical disadvantage versus older homes, but your own research suggest this is a diminishing effect, given that old homes are cold and/or expensive to run until they have had money spent on them, and I mean proper money, not just a Green Deal’s worth.)

I’m not saying this could happen overnight – it would of course take some time to build the expertise. But in what way is this not a desirable goal? How would using less energy not be more desirable than simply wasting energy (by building worse buildings than you could do), and getting someone else to produce some more low-carbon energy somewhere else – or getting them to save some energy that they should be saving anyway?

Given that ultra low energy homes (and buildings of all kinds) are desirable, feasible, affordable and indeed necessary, there isn’t any excuse for not starting out now on a clear path to bring all new homes to a proper truly low energy standard, delivered via the fabric, so it’s built in.  Zero Carbon and allowable solutions are by contrast an unforgiveable diversion up a blind alley.”

Allowable Solutions Consultation – silly policy, but still worth responding

Plenty of scorn has been poured on the way that the zero carbon homes target has been watered down, then watered down again, as if it were a homoeopathic remedy for climate change.

Others, notably Nick Grant and Doug King, have led the charge against the very concept of zero carbon buildings as being an illogical concept that diverts construction from what it could be doing best — and I cheerfully count myself among their followers.

However, on the particular point of the current government consultation on the Allowable Solutions element of “Zero Carbon Homes”, I do think it is worth engaging – as there is an opportunity to make the arguments that high fabric standards should be at the heart of the zero carbon policy. Who can say how long the Zero Carbon Homes policy will last? – however, the better the fabric standards we have at the core of it, the better placed we’ll be to replace it with something more sensible.

I have had a look at parts of what DCLG is consulting on, and describe and comment on what I found, in the article below.

Download Article on Allowable Solutions Consultation October 2013 (pdf)

The article also contains the links to the DCLG consultation documents.

STOP PRESS! Doug King has shared his response to this consultation, making the case very thoroughly that “offsetting” energy use and carbon emissions from housing, by reducing energy use and emissions in other sectors, is a nonsense. Those other sectors should be making those cuts anyway – all selling them off as “allowable solutions” does is to pick off the low-hanging fruit from another sector, making it more expensive for them to do what they need to do. The net effect would probably be to reduce energy use an emisissons LESS than you would if proper energy and carbon standards were applied to housebuilding in the first place.

Read his response here:






The Green Deal and the ECO

This article, originally pubished in Green Building Magazine (Spring 2013) is the second part of my look at the Green Deal, and considers whether and how the Energy Company Obligations (ECOs) might work, and whether and how individual contractors and householders might be able to take advantage of them to help install solid wall insulation, in particular.

I concluded that it was quite unlikely that most private SWI intallations (outside of some defined areas/categories of deprivation) would qualify for 100% funding, because the energy companies will be chasing the cheapest “carbon points” as calculated in SAP – but useful grants might be available for households who were keen enough to fund the difference themselves. It was also not yet clear how smaller and independent contractors might secure ECO funding for their customers, and thus, work for themselves – however, various avenues look possible.

In short, the ECOs should offer some help to some people, but are far from bridging the yawning gap between what the Green Deal can achieve (rather little, see previous article on the Green Deal) and the 80-odd-% cut in energy consumption/emissions that we desperately need to achieve. I suggest that as energy efficiency benefits building occupants, public services (notably health & education), the benefits bill, energy security and the cost of energy, and the balance of payments,  then perhaps all these benefiting entities and sectors should be contributing in a co-ordinated way.

View/download The Green Deal and the ECO (pdf – version without illustrations)

And here you can download a pdf of Green Deal and the ECO as it appeared in the magazine, complete with illustrations.

How important are embodied energy and embodied carbon?

This two-part article appeared in Green Building Magazine in Spring and Summer 2012.

I looked at the relative importance of embodied and operational energy and carbon – very much a subject of ongoing debate. I found that operational emissions were still relatively ‘bigger’ and should remain a priority – though embodied emissions should certainly not be ignored, and indeed may be more significant than sometimes appreciated, if their timing is taken into account. This is because they tend to happen ‘up front’, leading to more cumulative emissions in our current era.

However, I found reassuring advice from a number of sources that in general there should be no need to compromise operational performance when designing buildings, even if you are set on minimising the embodied impact too – in other words, fabric efficiency needs not have a high embodied cost. Indeed, as Mark Siddall (of LEAP) pointed out, low embodied impact and low operational impact can go hand in hand when it comes to the basics: compact, uncomplicated, modestly-sized buildings.

(There may be an exception when it comes to attemtping to “cut” operational emissions by adding renewables, which may have a significant embodied impact, despite the lifetime “savings”.)

Although rules of thumb can never substiute for ‘doing the numbers’, deriving figures for the embodied impact is not straightforward, with competing calculation methods and more and less transparently-derived data on offer, and little consensus. Progress is being made though, including some work that has been done since these articles first appeared; I gave a few examples of projects that were just getting under way a year ago, which may well be worth following up now.

In the second part of the article I also considered another sort of “offsetting” – the idea that the carbon sequestered in biological building materials such as timber and hemp might be subtracted from, or claimed as credits against, the operational emissions of a building.

I was not  (and continue not to be) keen on this idea, resting as it does on the presumption that ‘replacement’ plants will be grown elsewhere (ie probably not on the roof of the building!) – and to be punctilious, it also assumes that those plants would not have grown, had the materials not been used. This is the same line of argument that has led me to challenge the presumed carbon neutrality of biomass burning – see other posts on this site.

However, there is no need to cite the sequestered carbon to justify the use of many ‘natural’ materials (notably timber), as they can have a remarkably low embodied impact compared to their manufactured alternatives – though as suggested above, glib assumptions are never a substitute for checking the figures wherever you can.

The article is in two pdfs, to view or download here.

Embodied energy – a ticking time bomb? Part 1

Embodied energy – a ticking time bomb? Part 2