FactCheck: zero-carbon homes

How realistic are government promises for zero-carbon homes by 2016? The FactCheck Green series continues.

The claim
All new homes will be zero-carbon by 2016
Department of Communities and Local Government

The background
It's generally accepted - and not just by the front pages of the Daily Mail - that decent housing is in short supply.

The number of households in the country is, according to government projections, set to increase by more than 223,000 each year until 2026 - partly because people are living longer, and in smaller units.

Just over a quarter of the country's carbon emissions - scourge of climate-change campaigners everywhere and something the UK is committed to reducing in accordance with the Kyoto protocol - come from our households.

At the moment around 160,000 new homes are being built a year - a number the government plans to increase to 240,000 a year by 2016.

Government policy now states that all new homes will be zero-carbon by 2016. But can so many new houses really be as cosy as they sound for the environment?

The analysis
Before we can work out how helpful the policy is, it's important to see exactly what it means. Zero-carbon is not to be confused with "carbon neutral", which is to do with offsetting the impact of emissions by other - arguably less useful - actions, such as planting trees, rather than blitzing the source of the carbon.

Instead, over a year, the house needs to have zero "net emissions" of carbon dioxide from all energy use - including hot water, cooking, and the powering of TVs, computers and other appliances - in the home. How does it work?

Energy-efficient design means the house produces as few CO2 emissions as possible. Top-notch insulation could keep it heated by the warmth from other appliances, and rain water could be collected.

As it's not possible to produce absolutely no carbon, the house would "give something back", perhaps excess energy produced through microgeneration such as solar panels may be stored up over the year, and then sold back to the National Grid. It's not strictly true, however, to say that every single house would be zero-carbon; generally, a development or community would be carbon-zero overall, perhaps sharing renewable energy sources such as wind turbines.

Currently, there are a handful of carbon-zero houses. So how do we get from this situation to making them the norm, in just a decade?

Targets
The government has set interim targets, tightening the energy-efficiency building regulations in 2010 and 2013. A host of key players, including the Home Builders' Federation and a number of builders and developers, have signed up to a pledge of support for the 2016 target.

Some campaigners, such as Friends of the Earth, say that houses should be made carbon-zero sooner or by 2010 at latest.

As well as greenifying the homes, the people who live in them also need to be targeted. To put it crudely, there's little point in building a beautiful, energy efficient house if the owners are then going to fill the garden with outdoor heaters and gas-guzzling 4x4s.

"It's known as the rebound effect - if something is seen to be more efficient, people just tend to use more of it," says Yvonne Rydin, Professor of Planning and the Environment at UCL.

"Consumer acceptability and compliance is an important issue: there's no point providing homes that people don't want to live in."

It is important, she says, to give financial incentives to keep people living low carbon lives. The removal of stamp duty - the tax paid by buyers - on zero-carbon homes is a good start, but needs to be stepped up.

Impact
This brings us onto the question of how much impact these new homes have on household carbon emissions.

On the one hand, each year new homes account for only one per cent of the housing stock. A drop in the cul-de-sac on an annual basis, but by 2050, the government points out, the new carbon-zero additions will make up one third of the housing stock in existence.

On the flipside, of course, that means two thirds of the predicted housing stock in 2050 are already up and emitting. What about those two-thirds? Shouldn't we be more concerned about this greater number?

It's easier, and cheaper, to focus on new homes rather than trying to update existing homes; house builders and developers can be targeted, rather than trying to persuade a far greater number of individual homeowners to take action. It's also a good way of trail-blazing, and inspiring people to change.

As Sue Innes, Director of Sustainability at industry improvement body Constructing Excellence in the Built Environment, says: "It's really important that the target doesn't slip. Now it's been set, it's something that we should aim for. Relaxing it would send out the wrong signals to the industry and to everybody."

This isn't to say that the new plans are so good that the environmental effect of existing homes can just be written off - in fact, the Communities and Local Government select committee has just launched an enquiry into the role of existing housing stock in climate change.

It's also important to remember that, under the current plans, even the best-behaved houses are only counted from the time they are born as the carbon-zero promise doesn't include the impact of the construction of the house. This, says Innes, should be the next step.

The verdict
With household emissions making up such a large part of the UK emissions, the Government is taking a relatively bold move to cut one if the sectors responsible for many of our carbon emissions.

At first glance, it can be easy to say that new housebuilding - any kind of building - must be bad. However, short of turfing everyone out of their homes to live in teepees, houses are something that the UK needs, and so setting strict guidelines for new homes seems a step in the right direction.

There's still an element of wait-and-see about the whole thing, however: if the government's target is to be met, it calls for a wide stepchange in behaviour in the people living in homes as well as their makers.

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