It is probably the biggest financial purchase you will make in your lifetime and your choice has been based on many factors such as availability, price, good neighbourhood, correct number of bedrooms, garden, etc etc.

However what would you look for when it comes to a buying a property from a sustainability point of view. The advice is broken down into three catorgories, general, new houses & old houses.

General

If you need a mortgage, then why not consider a ethical and ‘green’ mortgage. These mortgages ensure the bank does not invest in companies or countries which cause instability around the world. A ‘green’ mortgage refers to a mortgage which has environmental benefits, such as balancing a percentage of the carbon dioxide emissions emitted from the dwelling using fossil-fuel sources such as electricity from the grid, fuel-oil or natural gas.

Is the dwelling south-facing> which is almost essential if you are considering installing renewables which utilise solar energy.

New houses

Houses from developments that started after May 2006 will be given a SAP rating which is based on a scale from 0 to 100, which is also given an A to G rating to fall in line with the EU energy-efficiency labelling scheme (Note: this SAP rating is very different from the houses on developments started pre-April 2006).

Was the house certified (check that your plot was specifically part of the EcoHomes Standard) as part of a development which attained an EcoHomes rating from Pass (Good, Very Good) to Excellent. EcoHomes is a sustainability rating which assesses a development on a range of topics from water efficiency to local ecology to substantial daylight and many other areas. A Pass rating is a reasonable effort over a bog-standard development. However when the development gets to Very Good and Excellent, the developer has had to go to a lot of trouble to achieve this standard.

If the dwelling is heated using natural gas or fuel-oil, then ask if the boiler is Sedbuk A (over 90% efficient for gas, and 95% efficient for oil) condensing boiler with a NOx emission class 5.

What are the u-values for the different building elements? A u-value is simply the amount of energy which flows through a square-metre of wall when there is one degrees Celsius between the inside and outside.

We would recommend the following:

• Floors – No greater than 0.22 w/m^2K, preferably 0.18 to 0.20 w/m^2K

• Walls – No greater than 0.32w/m^2K, preferably 0.25 to 0.30 w/m^2K

• Roofs (insulated ceiling) – No greater than 0.16w/m^2K, preferably 0.15 w/m^2K

• Roofs (sloped ceilings) – No greater than 0.22w/m^2K, preferably 0.18 to 0.20 w/m^2K

• Windows – No greater than 1.8w/m^2K, preferably 1.30 to 1.60 w/m^2K

• Doors – No greater than 1.8w/m^2K, preferably 1.1 to 1.3 w/m^2K

Old Houses

If you are buying an old house then it may have a lot of potential to make it energy efficient including unfilled cavity walls. We would recommend you take a look at our Energy Efficiency section to consider the potential improvements you might be able to make.

If the dwelling was constructed between 2002 and 2005 then it may have already been insulated in the floors, walls and roof and it is worth asking.