Cooling your house
In some areas of New Zealand, homes get so hot that people resort to active cooling systems like air conditioning. Yet there are a range of things you can do to make your home cooler without adding much to your electricity bill.
Ways to stay cool
The most effective way to deal with excess heat is by planning your building design (or renovations) around where the sun and breeze come from.
Window shades such as blinds, louvers or overhangs are a good way to reduce heat gain through windows in summer.
Planting evergreen trees that shade the north and west sides of your home in summer can help avoid overheating. But careful sizing and placement of windows will stop the problem happening, too.
A well insulated house doesn't just stay warmer in winter, but is cooler in the summer months too.
Plan for summer cooling
Use these tips to help reduce heat gain:
- Draw curtains over north facing windows to keep out the heat of the mid-day sun
- Create cross-draughts by opening doors and windows.
Cross-ventilation can provide most of your summer cooling needs:
Checklist
Consider how you can shade windows to help cool your home:
North-facing windows
Shade north-facing windows to prevent high summer sun entering the home. It’s important that shading devices don’t shade the windows in winter. Correctly designed eaves will do this. Otherwise look for something adjustable that gives you more control over how much heat you let in.
East and west-facing windows
East and west-facing windows should be well shaded from the morning and afternoon summer sun. This is done best with adjustable vertical shading like awning blinds, which cover the whole face of the window.
Vertically mounted trellis, low bushes or external blinds that block the low angle of the sun are also suitable.
Passive cooling
There are various types of passive cooling systems available. These make use of ceiling and roof vents or chimneys. They use the heat of the sun to draw hot air out of a house. These sorts of systems are more common in countries like Australia where cooling is more of a concern.
Don’t forget the good old ceiling fan. They are relatively cheap to buy and install and cheaper to run than air conditioning. They’re especially good if you only get a week or two of really hot days a year.
Active cooling
If you do need active cooling then there are ways to make sure your air conditioner or heat pump will cool effectively and as cheaply as possible.
Sizing - the same rules apply for cooling as for heating. A heat pump the right size will cool your house properly without having to work too hard.
Usage – again, as with heating, how you run your heat pump for cooling has a big effect on how much it adds to your electricity bill. For more information, see this site’s section on heat pumps.
More information
- The Department of Building and Housing provides a comprehensive discussion of cooling options
- Green Building resources and design innovation
- Find out about cooling with windows at the Window Association of NZ website.
