Improving Home Energy Efficiency

The Housing Executive is the Home Energy Conservation Authority for Northern Ireland. It was appointed to this role by Act of Parliament in 1996 and given a role in trying to improve the energy efficiency of the existing housing stock, both private and social, by 34%. The Housing Executive has carried out traditional energy efficiency schemes involving insulation measures and the installation of high efficiency boilers and low energy appliances. In addition, it has been involved in a number of schemes which involved the installation of renewable technologies, including solar thermal and photovoltaic panels, wood pellet boilers, domestic combined heat and power pump boilers, ground source heat pumps, wind turbines and solar ventilation systems.

The clear message that has come out of all these schemes is that insulation is the most important and cost effective energy efficiency measure that can be carried out. The fabric-first approach, where the dwelling is highly insulated and draughtproofed, will result in higher comfort levels and lower heating requirements, which also translates into cheaper energy bills at a time of escalating fuel prices. Insulation and draught-proofing should always be the first options considered before any thought is given to installing renewable technologies. With higher levels of insulation and airtightness, there is a greater need for mechanical ventilation, preferably heat recovery ventilation.

This will provide a more comfortable and healthy living environment, and will ensure there are no build-ups of condensation, mould growth or airborne pollutants. Once the fabric of the house has been dealt with, it is now time to think of renewable technologies. Any renewable energy installation should be carried out by a Microgeneration Certification Scheme (MCS) qualified installer – and only after expert advice is obtained or a scheme is designed by a suitably qualified person, e.g. solar thermal panels should be sized to the hot water requirements of the dwelling and are only suitable on a correctly orientated roof. The ground loop of a ground source heat pump (GSHP) needs to be carefully designed to ensure that the surrounding ground can recover the heat extracted by the loop and is correctly sized to provide sufficient heat to the dwelling. Renewables are not suitable in every case, so it is essential to get expert advice and guidance.

When installing a new boiler, it is a Building Control requirement that a high efficiency condensing boiler is installed. There are alternatives to oil and gas such as a GSHP or wood pellet boilers. A GSHP is better suited to a new highly insulated dwelling, as it normally requires an underfloor heating system which is difficult to achieve in a retrofit situation. Wood pellet boilers offer cheaper running costs – they are clean burning and the fuel is easier to budget for than oil, as well as being produced locally. Anyone thinking of building their own house should consider passive construction. This is a form of construction that requires very high levels of insulation and airtightness, which means that a conventional central heating system is not required. This means that for an initial outlay at the building stage, massive savings can be realised for the life of the building. Even if someone decides not to go for full passive construction, there is still a lot to be gained from abiding by some of the basic principles of the construction method. For further information, visit www.nihe.gov.uk