Renovating a house
House renovations are an opportunity to provide good comfort levels and services while significantly reducing energy use. This needn't cost much more than a less efficient renovation. When renovating, you need to consider:
- Insulation
- Blocking draughts for airtightness
- Double-glazing.
In the long term, it's much better to spend a little extra up front when renovating. The alternative could be higher energy bills for years or decades after, especially if the recent increases in energy costs continue.
The new Building Code applies to any major renovations. This has a minimum requirement for thermal resistance (insulation level) of exterior walls, ceilings and windows (the building's thermal envelope components). You can find further information on the Department of Building and Housing's website.
If you are renovating on a small scale or one room at a time, take the following into consideration.
Insulation
A bare minimum when renovating is insulating the ceiling, and if possible under the floor (EECA doesn't recommend underfloor foil products). The next step is to insulate the walls. To do this, you need to take the wall linings off, install insulation and re-line the walls. Find out more about insulation.
Airtightness
Older houses often leak a lot of air. Think of this as uncontrollable ventilation that removes heated air from your home. Problem areas include:
- unused chimneys
- holes cut in walls and floors for plumbing and wiring
- cracks between floor boards
- broken windows
- badly-fitted windows and doors
- walls cavities that are open to under the floor and into the ceiling space (air can flow through them) and have electricity sockets and switches in them.
A good start is to:
- close gaps
- block unused chimneys
- seal obvious holes and gaps with sealant and expanding foam
- put seal strips on doors and windows.
On top of this you might consider installing airtight membranes. These can be fitted to ceilings and under floors relatively easily. Like insulation, they can only be added to walls when you have the internal lining removed.
Dampness
Fixing dampness, mould, mildew and musty smells isn't hard when you renovate. Wet steamy areas - such as kitchens and bathrooms - should have good extractor fans vented to outside the house. Venting into the ceiling space is not only bad for your house and health, but is also illegal.
Damp air rising from under the house is often a contributing factor to dampness in the house. Houses with continuous perimeter wall foundations are prone to moisture build-up. This is especially a problem when the underfloor area is not properly vented. If your house has this type of foundation, consider putting down a ground vapour barrier.
Double-glazing
Replacing old windows with double-glazed units can significantly reduce the heat loss from your house. Double glazing also reduces condensation and can reduce the amount of outside noise coming into the house.
Space Heating
Once you have draughts, dampness and insulation under control, the next step is to think about space heating. Have a look at information on each type of heating and cooling.
More information
