Is current Part L the optimum standard for houses?

[Ballard]

Had a great CPD from these chaps...

http://www.super-e.co.uk/Homebuilders/zero-carbon.htm

(Yes Ken, some of us evil architects do care)

Very good, the basic message was that the uk's messing around trying to get solutions to zero carbon etc..

It was all solved years ago by Passive haus, and the Canadian equivalent Super-E housing.

There are approximately five things to do...

1. Orientation, maximise winter sun, minimise summer overheating
2. Insulation, high as reasonably possible (they think PH overdoes this)
3. Air leakage, very important must be less than 2 , not 10 as Uk standard
4. Heat recovery ventilation, at up to 90% efficiency this is vital.
5. VOC's, now the house is sealed, be very careful about internal finishes.

Finally lifestyle.. this all means nothing if you fill your house with plasma TV's and fly all over the world etc.

[kenneal - lagger]

Well done, Ballard, I know there are some very good architects but, unfortunately, in general they are as ignorant of the Passivhaus standard as the general population. I have often had to try and pick up the pieces at Building Regs stage after an architect has handed over a basic design when the client wants a low energy design. Bill Dunster told me that he has to train a new architect for about 2 years before they are any use to his practise. I was also talking to an architect at CAT last year who teaches at an architectural school and she said that they were still not teaching low energy design at her school.

It is almost criminal really as low energy design should be the bedrock of any architectural design course. It should be the first thing considered as it effects the whole concept. You can't design a building and then retrofit it to Passivhaus or Code Level 5 or 6. It has to be there from the start.

As you say orientation, degree of fenestration and compactness are fundamental to any energy efficient design and any half decent Passivhaus will come in at under 1ac/hr. I'm still inclined towards the Passivhaus insulation levels because I think in the future we will need to use as little energy as possible. I think those insulation levels are at the kicking point on the exponential graph where the added insulation width goes ballistic for very little improvement in energy saving. IMO it's far better to use any oil we have now to manufacture insulation and sequester it in a building for two or three hundred years than burn it in a car.

At least CAT are now offering a Part 2 course on Advanced Environmental and Energy Studies similar to the MSc which a few of us here have done/are doing.

Very good, the basic message was that the uk's messing around trying to get solutions to zero carbon etc..

It was all solved years ago by Passive haus, and the Canadian equivalent Super-E housing.

I couldn't agree more. The main reason Code for Sustainable Homes was bought in was to give BRE another funding stream. Virtually everything in the Code could have been put into Building Regs and been applied far cheaper, especially for small developers. The best thing that could be done now is to upgrade Building Regs to Passivhaus levels of insulation, bung in all the other provisions and scrap the Code.

I don't like the Super-E house's reliance on a heat pump for heating and cooling though. It's probably a light weight construction so may require cooling during summer days. I'd much rather rely on night time cooling of thermal mass which is free. Because of its Canadian origin I suspect that the night time conditions in a Canadian continental summer may not provide low enough temperatures to allow this. It's one of the dangers of importing foreign designs unquestioningly.

Rant over and, again, well done.

[Ballard]

I don't like the Super-E house's reliance on a heat pump for heating and cooling though. It's probably a light weight construction so may require cooling during summer days. I'd much rather rely on night time cooling of thermal mass which is free. Because of its Canadian origin I suspect that the night time conditions in a Canadian continental summer may not provide low enough temperatures to allow this. It's one of the dangers of importing foreign designs unquestioningly.

Yes, I used night time cooling on a FE college project I designed, using stack effect, exposed thermal mass ceilings and floors, and large automatic opening vents next to the windows, at night the vents would open in the walls and the top of the atrium, and let all the hot air out... The cool air then chills the thermal mass (in this case lots of concrete ). The building then closes up ready for the day's activities.

However...

They then proceeded to put twice as many people and six times as many computers into the building that it had been designed for (with their input of course). They also left all of the equipment on all night, acting as a large electric heater... and then moaned continuously about it getting too hot. The night time cooling effect was no match for all that fossil fuel energy being poured in the building... Last time I was back they had rigged up some portable air-conditioners.

The lesson I learned was, people do not follow instructions no matter how clear. It is often best to opt for a really efficient mechanical system and make all the other possible improvements, you can do all the thermal modeling you like, but you cannot predict the actions of the occupants.

[kenneal - lagger]

Don't be embarrassed about using concrete. It's a very good material used in the right way in the right place, which is how you used it, Ballard.

When engineers do structural calculations they always use a safety factor to guard against overloading. Perhaps that might be a useful safeguard next time you are given a brief. And maybe have an IT power circuit with an automatic switch on it.

[biffvernon]

Be very embarrassed about using concrete, one of the worst greenhouse gas offending products in the world.

[contadino]

Oh Biff, get down off that high horse once in a while.

The cement industry suffers the a similar problem as FFs - namely, a few major players suppressing innovation in alternatives.

The only people who should be embarrassed are the cement companies.

[biffvernon]

Oh Biff, get down off that high horse once in a while.

Why?

[Ballard]

Ken, yes both of those things were done, but more than a 25% safety factor is prohibited by cost (bigger vents, etc). IT circuit as well, but they won’t switch it off because of the hassle of rebooting apparently.

Be very embarrassed about using concrete, one of the worst greenhouse gas offending products in the world.

Yes agree in principle, unfortunately (despite belief to the contrary) architects are now generally only a small element of the construction team, for the most part these choices are made by the Quantity Surveyors and developers. You are generally told what the structural frame will be and this is driven by cost, you then try to take the greatest advantage of the materials you are given.
I generally suggest limecrete and hemcrete blocks as a preferable alternative, but clients tend to lose interest when they discover that it’s twice the price...

http://www.limetechnology.co.uk/index.h ... mcrete.php

http://www.limecrete.org.uk/

http://www.limecrete.co.uk/limecrete_feb_09_002.htm

[kenneal - lagger]

Fuel costs will sort it all out in the end. They'll have to use the building as it's designed to be used.

[biffvernon]

driven by cost

Oh, that is so true. The whole building industry has become addicted to stuff that costs a lot because that's where profits can be made. We no longer use earth because if is essentially free and so nobody can make money out of it. We have become persuaded that the more expensive something is the better it must be. It's all a big con.

[adam2]

Whilst I would agree that something better than part L should be aimed for, it must be said that even part L is widely flouted,evaded or circumvented.

Office buildings, new or old are often appaling wastefull of fuel.

I have heard more than one architect or designer state regarding a new build office "we had to put in those silly low energy lamps to satisfy the tree huggers, but dont worry, all the fittings are compatible with proper halogen lamps"

At one building that I maintain, the gas boilers hade been on 24/7 for YEARS because the controller was defective and "we dont have the budget to fix it" The payback time for a simple timeswitch was less than a week !

And "renovation" of offices or homes still consists of installing dozens of halogen downlights.

I have only known one building where natural overnight cooling was attempted, it did not work because it resulted in early morning space temperatures of "only" 22/23 degrees, at which point numerous electric heaters were used.

I have also seen many buildings with central heating and A/C that would work effectively but for all the electric heaters.

[kenneal - lagger]

The whole building industry has become addicted to stuff that costs a lot because that's where profits can be made. We no longer use earth because if is essentially free and so nobody can make money out of it. We have become persuaded that the more expensive something is the better it must be. It's all a big con.

That's 180 deg wrong, Biff. Earth is not used because the labour content is very expensive, while things like concrete and bricks are cheap, on the back of cheap fuel costs.

All building work is won in a competitive tendering process. The cheapest of every thing is used unless a more expensive option is specified. Architects design to a specification and a budget. If a certain spec comes in over budget the client will usually change the spec for a cheaper material. We have become addicted to the cheap in everything; just look at supermarket advertising - all based on cost.

Except for a few prestige projects, architects will go for the cheapest structure so that they can put in some bling with loads of nice halogen spots. Most architects, Ballard and a few others excepted, are solely concerned about looks: the design starts off with a concept sketch and is developed form there. Orientation, insulation and mass come in last.

[kenneal - lagger]

Here are some entries from the other site I post on with my replies -

It depends what you are tryin to optimise!! Maximum profit for insulation companies - then Passivhaus win… HAHA
I don’t really mean that – but this blanket approach to insulation is not the way forward!
The first questions is was what is optimum level of insulation before benefits stop??
That is – what is the point of thermal inflexion? Each case is different – but resent research suggests that there is a strong possibility we are over insulating our homes!!!!!!

The first question you have to answer is "Does Britain have an indefinite supply of affordable heating fuel?"

If you think that we have enough affordable heating fuels to last for the life of the house you are going to build, and I say that should be at least 200 to 300 years or more, then optimise your insulation using a cost/benefit analysis.

If you believe that the world, and Britain especially, will face a shortage of affordable heating fuel in the near future, it makes sense to insulate to a level where a heating input is not necessary for most of the time. PassivHaus levels achieve that. I do agree that if you go much over Passivhaus levels you may well not get the embodied energy in the insulation back.

If you want to eradicate fuel poverty, eradicate heating. - Passivhaus.

Even the IEA is coming around to the idea of Peak Oil in the near future. The government is worried about fuel security in the near future. China is still growing at 8% per year despite the recession which means that they will at least double their consumption of everything they import within 9 years. That means their coal, gas and oil imports will double. That will put huge pressures on global prices and supplies.

What level of fuel price inflation do you use to measure the correct level of insulation in these circumstances?

resent research suggests that there is a strong possibility we are over insulating our homes!!!!!!

That research must have been done by an economist, because they are the only people stupid enough to believe that growth can be infinite. Either that or it was done by a company trying to sell micro CHP where the heat output is four times the electricity output. In that case to get say 2kw of electricity you have to find a home for 8kw of heat to make the system stack up economically. You don't want the building to be too well insulated in that case. You do have to believe in an infinite supply of cheap gas though.

If you believe in Business as Usual in the future, our houses may well be over insulated. If you believe, as I do, that the next twenty five years won't be the same as the last twenty five, then it's Passivhaus for everyone.

To answer your points.
1 The UK does not have an indefinite supply of affordable energy (for heating or cooling) nor does the rest of the world… and even if there was it does not mean you can waste it…. Cooling is a real issue. Over insulating can add to overheating – each case is different – you may well need meters of insulating on a north facing, windward wall in some parts of the country BUT many parts are damp and mild…. You cant apply the blanket approach – an understanding of the immediate environment is the most effective way of managing fuel both for heating & cooling! its not just insulation its glazing too!

With a light weight house cooling could be a problem. With a heavy weight one you can use night time cooling to keep a house comfortable during the day and proper insulation is an important part of that.
Passivhaus standards require a maximum of about 300 mm of wall insulation, depending on the type chosen. Meters would never be necessary in this country, unless it was not very good insulation. A Passivhaus, or indeed any passive, design takes into account the design of the glazing and the heat input from it. It is easy to design out summer overheating if you are aware of the problem.

2. Adaptability…. More wind driven rain will change everything… as will an increase in direct solar receipt 300 years ago both life styles (thermal mass) were more important than the partial occupation or even multiple dwellings… most people don’t live in a little timber frame self build in the middle of nowhere! 50% of the global population lives in an urban environment! I think in the UK its around 70% - the real issue then is how do we manage the current building stock in with both an unsecure fuel and climate future – without even hitting on ‘lifestyle’ - 300 years is just dreaming…. I wanna get through the next 75 to 100 years without deaths from overheating alongside the coldness taken hold…. That’s not saying I don’t care about the future its saying I don’t know about the future… so maybe/maybe not to you point ‘optimise your insulation using a cost/benefit analysis.

The effect of wind driven rain will be to increase the heat loss in a badly designed house. With a properly detailed house and insulation system, wind driven rain won't make a significant difference because the insulation will be kept dry and the surface temperature won't be much higher than the ambient. Surface evaporation won't have much heat to leach away. I wouldn't advocate living in a timber frame house anywhere in England. Been there, done that and got the T-shirt because it overheated during the summer just from warm flow through the open windows. It had no mass to keep it cool. Any house built now will have to last hundreds of years, just like much of our current housing stock has, because we won't have the energy, or money, available in the future to mass build houses or "renovate" them. We need to build them properly now so that they are usable in times of energy shortage, both for heating and cooling.

3. research is showing overheating is becoming a problem… you have to think of the other angles as well, you can’t always open your windows… especially if you live in fear of crime… so it’s about the balance… not just about heating.

Overheating is becoming a problem because of the widespread use of aircrete light weight blocks, light weight timber frame houses and bad design with too much glazing. It is not because of over insulation. We only have about a dozen houses built to Passivhaus or similar standards in the country, so don't blame the problem on over insulation. If security is a problem use a secure ventilation system; they exist.

4. embodied energy - we agree here!

Good. The Balance of energy in embodied energy is effected by the length of life assigned to the material. Using a sixty year design life for a house skews the balance when a properly designed and built house should last somewhere in the region of 300 years.

5. I work for the EU – its fuel poverty is high on the agenda… BUT it’s not just heating

Good about fuel poverty. I can't speak for continental Europe and I don't design there, but with the UK's maritime climate cooling should not be a problem with a heavy weight, well insulated structure.

6. peak oil is not the only issue… what about pollution/ food resources medical and heath care, education, child labour – bla bla ba. These are real issues that come with our growing global population… im not saying use more fuel – cooling is harder than heating!

I know PO is not the only issue, there is Climate Change as well and, perhaps more importantly, the fact that the country is bankrupt and won't be able to afford to import fuel for much longer. The others don't have much effect on house design except that food supply could be effected if we use too much land to grow fuel to heat and cool houses which should be better insulated.

7. fuel price inflation – less fuel dependence I’m all in favour but as above cooling is more fuel hungry than heating! So it’s the annual balance!

As I have said, cooling is not a problem in a well designed, well insulated house.

8. The research I have read has come from engineers and architects… who have carried out through analysis, including post occupancy monitoring. I’ll find you some links! And my point about optimising profits for the insulation companies!!!

They can't have analysed many well designed and insulated houses because there aren't many in the UK at the moment. If you think that it is better to use less insulation than give profits to insulation companies use raw sheep fleeces or straw. They work just as well in the right place. Otherwise it's not a comment worth making.

9. I certainly don’t believe in business as usual – this includes the blanket approach that we are shouting about… I think each case is unique and its success is not based on how we are gunna live 300 years in the future BUT how are we gunna do it now - change is good… I believe in activehuse…

I went to a lecture from a DTI economist and was told that they had done studies which show that the UK has a heating shortage in the future. The economist also said that the present insulation standard of houses was good. This only goes to show some of the muddled thinking coming from government advisers. If we have an energy shortage with the current insulation level, increase that insulation level and the future shortage goes or at least decreases.
We need high levels of insulation now and those houses will have a life of 300 years or so, so the embodied energy in them is negligible compared to the energy used in an inadequately insulated house.