Under current UK government legislation all new-build homes must be zero-carbon after 2016. However, some of the major builders are trying to get a head-start on this deadline and have begun developing designs and prototypes already.

One such company is Barratt Developments - one of the UK’s largest firms - which this week unveiled designs for what will become the country’s first zero-carbon house built by a volume builder. The first examples of these homes will be available from 2011, in a 200 unit batch at the site of Hanham Hall hospital, near to Bristol.

All of this sounds great, except for one snag - the cost of the homes. Though Barratt have not specified the exact value, their chief executive, Mark Clare, has said that it will be ‘difficult to reduce the cost of the current prototype to commercial levels’.

Now, it’s all very well having lots of zero-carbon homes, but not so great if they all lie empty because nobody can afford to buy one… The question is; what can be done to avoid this situation from developing?

Well the simple fact is that such projects will require quite a degree of government assistance to succeed quickly. No doubt Barratt and other developers will do what they can do drive building costs down - but ultimately there is only so far this can be taken before we are left with a zero-carbon, but ugly and low quality home that nobody wants to live in.

In the first few years after 2016 (maybe even before) it will be crucial that the government subsidises the cost of such homes so that they can compete with the older properties on the market. Some measures have already been introduced, such as a stamp duty waiver until 2012 on zero-carbon homes worth over £500,000 (homes under that value are eligible for a £15,000 stamp duty discount).

This is a start - but hopefully only the beginning of a series of similar moves.

Barratt’s prototype for example utilises solar panels, rain-water harvesting, and an air source heat pump. It is these features, along with its super-insulation and triple-glazed windows, that have earned it the best possible energy use rating of grade 6 (signifying a completely zero-carbon home). Perhaps the industry sectors producing this technology could do with a few tax cuts, or incentives in return for helping reduce costs.

It is true that a zero-carbon home will face only very minimal running costs and hence a case for the higher asking price could be made on these grounds. The problem is that, if would-be buyers cannot even secure a mortgage for the house, the rest becomes irrelevant.

This is where banks have a part to play - by introducing a different mortgage option for buyers purchasing such homes they could be instrumental in the success of zero-carbon housing. With the current credit problems many banks have reigned in their mortgage options of late - but those buying a zero-carbon home in the future will have a greater ability to repay a big mortgage - due to the lack of gas and electricity bills. A bigger loan could therefore be repaid in the same time as a smaller one on a non grade 6 property.

There are many other potential measures currently being discussed - but the main point is that the government needs to seriously consider further legislation (or funding for buyer-assistance schemes) in order to ensure that the initial mandate of zero-carbon by 2016 is the success it has the potential to be. If this can be effectively managed then the (positive) consequences could be far reaching indeed - from the inherent environmental benefits, to reducing the cost (while raising the standard) of living in the UK. Let’s hope those involved can get it right, for we all stand to reap the rewards of this effort.

(A detailed image of Barratt’s design can be found here).

Dejan Levi