Cooling
- Overhanging eaves help keep the sun out during summer
What are the options for staying cool in summer?
Well-designed homes in most parts of New Zealand will make the most of passive cooling and ventilation. They should need little or no mechanical (or active) cooling in summer.
Mechanical cooling options run on electricity. Using them to cool your house in summer will add to your power bills, sometimes surprisingly so.
Passive cooling
Passive cooling includes shade to keep the summer sun out, good insulation and good ventilation. Take steps to create cross-draughts in your home in your design, and by leaving doors and windows open. Think about shading your windows with eaves, plantings, awnings or louvres, and thermal-lined curtains.
Passive cooling isn't just for new homes. Passive cooling features can be added to existing homes - it may be as easy as planting trees to provide shade or leaving windows open to get breeze circulating inside.
In most parts of New Zealand, even in summer, this should be enough to keep your home cool.
See Passive cooling for more in-depth information on designing for summer coolness.
Mechancial cooling options
Fans
If natural ventilation doesn't keep you cool enough, a fan may make you feel several degrees cooler - the air movement increases the rate at which moisture evaporates from your skin.
Fans are cheap to buy, easy to install and comparatively cheap to run. Portable floor and desktop fans are widely available, and can be stored away when not in use.
Ceiling fans
A ceiling fan circulates air in summer and helps to keep you cooler. In winter it can re-circulate warm air that collects near the ceiling.
A ceiling fan uses very little energy compared to an air conditioning unit. It needs a reasonable ceiling height to give good clearance and an electrical connection.
Evaporative coolers
Evaporative coolers are a form of air conditioner.
They cool air by evaporating water, so work best in dry climates. If humidity is high, as in Auckland, these coolers will not work well.
The National Institute of Water and Atmospheric Research's website has a web page showing monthly humidity averages around New Zealand.
The only energy used is for the fan, so evaporative coolers are reasonably energy-efficient. They use water and portable units must be topped up regularly.
To keep the humidity low, let outside air into your house.
Heat pumps
Heat pumps provide heating in winter, but most models can be switched to reverse - which means they can be used to cool your home in summer.
However, using a heat pump isn't an energy-efficient way of cooling. If you run it in summer to keep your home cool, you'll wipe out any savings you made on your heating bill in winter.
If you do use your heat pump:
- Try using the fan only setting to create a breeze.
- Use the dehumidifying mode to reduce humidity that can make it seem much hotter.
- Only use cooling mode on really hot days, shut doors and windows and only cool one room.
- Avoid using auto settings so that it doesn’t start heating when the temperature drops.
- Select a heat pump the right size for your home.
More information
From Smarter Homes
From Consumer
Note: You may need to be a subscriber to access some of this content.
From other sites
The Energywise website has information about cooling your home. Also see www.energystar.govt.nz for information about energy-efficient appliances.
The Australian Your Home website has good information on design and features for cooling your home.
The National Institute of Water and Atmospheric Research has a web page providing an overview of New Zealand's climate.
You can get local weather information from the MetService website.
