The UK Code for Sustainable Homes was a set of standards, launched by the UK government, to assess the environmental impact of new dwellings. The following guidance, published by the Department for Communities and Local Government in December 2006,  set out the minimum standards that a building needed to meet, in order to attain Level 6, which was the most exacting standard

The home will have to be completely zero carbon (i.e. zero net emissions of carbon dioxide (CO₂) from all energy use in the home). This could be achieved by:

• Improving the thermal efficiency of the walls, windows, and roof as far as ispractically possible (by using more insulation or better glass for example);
• Reducing air permeability to the minimum consistent with health requirements (a certain amount of air ventilation is needed in a home for health reasons);
• Installing a high efficiency condensing boiler, or being on a district heating system;
• Carefully designing the fabric of the home to reduce thermal bridging (thermal bridging allows heat to easily escape between the inner walls and the outer walls of a home);
• Using low and zero carbon technologies such as solar thermal panels, biomass boilers, wind turbines, and combined heat and power systems (CHP). It would mean for example that energy taken from the national grid would have to be replaced by low or zero carbon generated energy, so that over a year the net emissions were zero.

The home will have to be designed to use no more than about 80 litres of water per person per day. This could be achieved by fitting such items as:

• 6/4 Dual Flush WC;
• Flow Reducing/Aerating taps throughout;
• 6-9 litres per minute shower (note that an average electric shower is about 6/7 litres per minute);
• a smaller, shaped bath – still long enough to lie down in, but less water required to fill it to a level consistent with personal comfort;
• 18ltr maximum volume dishwasher;
• 60ltr maximum volume washing machine.

To achieve the standard would also mean that about 30% of the water requirement of the home was provided from non-potable sources such as rainwater harvesting systems or grey water recycling systems.

Other minimum requirements are required for:

• Surface water management – this may mean the provision of soakaways and areas of porous paving;
• Materials – this means a minimum number of materials meeting at least a ‘D’ grade in the Building Research Establishment’s Green Guide (the scale goes from A+ to E);
• Waste management – this means having a site waste management plan in place during the home’s construction, and adequate space for waste storage during its use.

But to get to Level 6 you need a further 64.9 points. So the builder/developer must do many other things to obtain the other points. In fact they will need to do 90% of everything in the Code to achieve Level 6, including:

• Energy efficient appliances, and lighting;
• Supplying accessible water butts;
• Reducing surface water run-off as much as possible;
• Using highly environmentally friendly materials;
• Minimising construction waste;
• Maximum, accessible provision for recycling;
• Improved daylighting, sound insulation and security;
• Building to the Lifetime Homes standard;
• Assessing and minimising the ecological impact of the construction of the home.

Download the full publication: Code for Sustainable Homes (PDF, 447 KB)

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