Extras Kevin: Ground Source Heat Pumps

Date Published:

02/07/2008

The science involved may be hard to grasp, but it’s easy to understand the benefits of heat pumps, says Kevin McCloud

I'm well aware that a number of technologies have spawned since we started filming 10 years ago. We’ve covered lighting systems, stereo speakers hidden behind plaster walls, some ludicrously hi-tech kitchens and even nanotechnology, self-cleaning, odour-absorbing paint. At times it feels like we’re making the series that answers all those Tomorrow’s World programmes of the Seventies.

Saving Money and Energy

But the really fascinating gadgets are not those designed to save us from getting off our lard-arses to open the front door, but the innovations that save us money and energy. There are sensor systems that switch off lights and turn down the heating when there’s no one in a room. You can even buy extension leads with remote controls to zap off all your entertainment equipment at the plug.

My own favourite techy devices tend to be the simpler ones, because I understand how they work. I can get my head round how the heat recovery unit works in my tumble dryer: cold, dry air is drawn in and then gets passed over a series of flattened tubes that contain the warm, damp air that’s getting exhaled. The heat is transferred, saving the machine energy. A heat recovery unit working in an airtight house works just the same and can extract 95 per cent of waste heat. So don’t install a boiler – design your house so you can fit one of these.

Heat Pumps

And then there’s the ground source heat pump, the Toyota Prius of home tech. I say this because like the Prius, which still drinks petrol as well as running on its own electricity, the heat pump still consumes electricity from the mains (up to three kilowatts for every five kilowatts it produces), making it a sort of variegated green product. It’s not as simple – or as miserly to run – as using solar panels to heat your water. I can understand those. Nor is it as ingenious as photovoltaic panels, which generate electricity from solar energy. They may be expensive now, but a brilliant new generation of cheaper, thin-film versions, like sticky-back plastic, are imminent.