Ceiling insulation.

A well-insulated ceiling is the first essential for a comfortable and energy efficient home. If the ceiling is uninsulated or poorly insulated you are unlikely to be comfortable no matter how large a heater or cooler you have. To find a contractor look in the Yellow Pages under Insulation Contractors.

Your recommended insulation level depends on your location. Check current recommendations at the yourhome website. I recommend you use the recommended insulation level for air conditioned homes, even if you rely on natural ventilation, as the more insulation you use the less likely you will be tempted to install air conditioning. If it is feasible to put more insulation in than the minimum, consider doing so. Although the recommendation is based on cost effectiveness, with increasing fuel prices it is worth considerring the next higher level of insulation.

If you can't afford to get it done professionally, buy a bag or two of insulation from the hardware store and install it above the most critical rooms now! Add to it progressively as you can afford it.

Wall insulation

Although wall insulation is desirable, it is usually considered impractical to retrofit to an existing home. However, if you do have to replace your gyprock lining or your external cladding, grab the opportunity and insulate. It will be well worth it. In addition there are some insulation types intended for existing walls (for example hydrophobic mineral wool cavity wall insulation). Traditionally the problem with blown wall insulation was conduction of moisture from the outside bricks to the inner wall. The manufacturers claim to have solved this, although I haven’t any personal experience with the current materials.