The energy-efficient home: insulation

Many houses are poorly insulated. As these tips will show, this fault can produce major gains in energy efficiency.

Choosing insulating material can involve many technical considerations; the recommended standards for insulating materials vary not only with the particular application but also according to the location of the house and its climate. Installation may require attention to matters such as access, fire safety and ventilation. Insulation may be readily installed in roofs and floors but existing walls can be difficult and costly to insulate, so it is important to obtain proper advice before starting the job.Insulation will not benefit all types of buildings equally; for example, a wood cottage with a wooden floor will still cool down quickly at night unless the floor has been properly insulated.

Attention should also be given to windows where loss of heat through unprotected glass can be considerable. Where the climate is cool to cold this may justify double glazing. In warm regions windows may be protected sufficiently by installing close-fitting, lined curtains hanging from a closed pelmet.Insulating materials generally fall into two types: bulk insulation such as fibreglass or reflective insulation such as foil laminates and blankets. A typical use of the bulk type is on top of the ceiling, while a reflective foil laminate may be used as a lining under roof tiles to reflect away radiant summer heat.

Insulation comes in different forms for different purposes.

1. Batts and blankets fit well between joists and studs; loose fill and pumped-in foam are used for areas more difficult to reach.
2. To insulate roof space, select batts or blankets so that they fit snugly between ceiling joists. Be sure not to cover any vents or light fixtures.
3. Loose fill works well above a ceiling on attic floors. Use a board or garden rake to spread it evenly.
4. Houses with cavity walls can be insulated with loose fill or foam that is blown or pumped in through holes drilled into outside walls. This job is best handled by professionals.
5. In cool regions, the undersides of floors open to the air or floors over cellars are worth insulating.
6. Press batts or blankets between joists, vapour barrier facing up, and secure with wire mesh or pieces of coat hanger cut to fit between joists.
7. Reflective foil sarking is a first line of defence, weatherproofing tiles and acting as a heat barrier.