Zero Energy Housing

20 April 2008

Interview with

Asif Din, Zedfactory

Chris - We're talking now to Asif Din who joins us now from ZEDFactory. He's one of the architects that's involved in BedZED. That's the Beddington Zero Energy Development. This is a housing development that produces or aims to produce all of the energy that it consumes within its site boundaries. That's a pretty ambitious target, Asif.

Asif - Yes! Hello.

Chris - How do you plan to do that?

Asif - It was originally planned to have a combined heat and power plant on site which has a capability of producing all of its electricity and hot water on site over the course of a year. During the winter it might import a bit of energy but during the summer it'll be exporting.

BedZED - The Beddington Zero Energy DevelopmentChris - The houses do need heating but you're doing it much more efficiently because you've got your own local power station basically.

Asif - As a matter of fact BedZED has as much insulation so you do away with having your usual central heating system. It's got virtually zero-heating dwellings but on the hot water side, you still have to provide hot water.

Chris - Sure, because you can't do without a hot shower every day!

Asif - No!

Chris - Talk to us about how architecture is going in terms of producing houses which we view are sustainable dwellings. What are the housing priorities?

Asif - One of the big ones is, As Dr Karl was saying, actually producing enough enrgy from your rooftop to actually power your home. Beddington Zero Energy Development does that on a site-wide scale but the actual aim would be to do it on a single house or retrofit a house so you can produce all of the energy it needs from your house.

Chris - They're twp rather different targets though, aren't they? Retrofitting my manky old cottage so that it was as good and energy efficient as one of the houses you're designing and building now is a very different target, isn't it?

Asif - It is, very different. There are certain things that you can still do. You can still buy A rated appliances so when you've finished with your washing machine or fridge you can get a more efficient one. By reducing the amount of energy you might be able to put a couple of PV panels on the roof and power a few bits and pieces of your house.

Chris - What about in terms of the way houses are laid out? It's very much en vogue at the moment to have your own dwelling which is a detached cottage but that's got four walls which are exposed the elements therefore the heat loss must be big. Should we be going back to the Victorian era where everyone lived in terraces?

Asif - BedZED is actually arranged in terraces and yes, if you are living in an apartment building or something that's surrounded by quite a few on the sides then yes, you are going to consume a lot less energy than having an exposed cottage in the middle of nowhere being swept with wind.

Chris - What about government regulations? What's the government saying we should do when we build new houses and make sure they're energy efficient and don't relase excess carbon dioxide into the air?

Asif - The government has put together a code for sustainable homes which next year will become mandatory for housing associations. It will be what's called code level 4 which will slowly ramp up until, I think, it's 2018 when all of their homes should be zero energy or zero energy target.

Chris - Wow, when you say they're zero energy they literally are not net consumers of energy?

Asif - They're not net consumers of energy. They produce all of what they require from their own site boundaries.

Chris - But how? I know how much energy my house uses. How is that achievable?

Asif - It's actually starting from the very basics. It's about lifestyle, it's about using the right appliances, energy efficient appliances. It's also, as I said, putting enough insulation in the wall so you don't actually need a proper heating system.

Chris - If you put lots of insulation in the walls the walls are much thicker and developers don't like that because they can't get as many houses on the site.

Asif - Yes but they will save on not having to put in a central heating system so it's balancing one thing with another.

Chris - When you say a combined heat and power station, tell us a bit about how that would work and how it's laid out. Why won't there be pollution tipped onto the houses, having that in their back yard?

Asif - It's quite a clean-burn technology. The one at BedZED was a modified diesel engine,  effectively that takes the gas off woodchip then puts it through a processor which then produces energy from a turbine. The turbine has a jacket of water around it and that produces its hot water. Rather than having huge cooling towers as you would do in a proper power station the heat is not dumped and it's actually used for a good purpose.

Chris - How many people can you have in one of these developments benefiting in this way? What happens when it goes wrong in the middle of winter? Everyone's cold?

Asif - You would always have a back up of some description.

Chris - Hot water bottle?

Asif - No, it wouldn't be that bad but you would have, say, an immersion heater on your cylinder like you would do even now. If it does break down at any point you would still get hot water.

Chris - How much do you think you can save people in terms of their household bills in the houses you're designing now?

Asif - BedZED's proving to be a 90% reduction on space heating, about a 50% reduction on water and about a 50% reduction on electricity.

Chris - Those are pretty impressive results.

Asif - They are.

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