Keep Cool and Carry On
This record heat may be great for growing veggies and hanging down at the beach, but it proves challenging to carry on with every day life when the inside temperatures soar too. Staying comfortable at home and in the office is easier in an energy-efficient building.
In the South Island, we have a tendency to focus on the need to keep our homes warm and dry. Thermal efficiency also refers to keeping a home cool in the summer.
Well insulated walls not only keep heat in during the winter, but also keep the heat out in summer. A good thermal envelope will retain internal temperatures better, so less artificial heating or cooling is needed to keep the inside at an optimal level of comfort.
The best time to integrate energy-saving tips is in the design stage. Passive shading means orienting the home to capture the northern sun during winter and block out the excessive rays of the western sun in the summer, and well-designed eaves allow maxium sunlight to enter the home during the winter and keep it from shining into the house in the summer when the sun is situated higher in the sky.
While these ideas can be difficult to include retrospectively, here are ten tips to help any home stay cool so that its occupants can carry on in comfort:
- When the outside temperature is cooler or a breeze is blowing, keep windows open -if your house is empty during the day, install restrictor stays that allow the window to open to a minimal angle for security reasons.
- When the outside temperature is warm, keep the house closed and blinds drawn during the day and open it up once the temperature starts to drop.
- Cross ventilate-create air flow by opening windows on opposite sides of the house.
- Take advantage of the fact that hot air rises (think hot-air balloon), and create a natural draft by opening downstairs windows on the shady side of the house, and upstairs windows on the hot side of the house. Increase this natural flow by putting a portable window-mounted fan in the upstairs window. If there is any natural breeze, “tune” your windows to work with it: Open downstairs windows on the side of the house the wind is hitting, and upstairs windows on the side of the house away from the wind. As the wind swoops over and around your house, it actually decreases the air pressure on the far side, and that lower pressure will pull hot air out of your home. This is called the Stacking Effect.
- Use a Shade sail or retractable awning can act as a temporary eave in summer.
- Landscape with deciduous trees to create shade in summer.
- Consider installing a Heat Pump, which is not only an energy-efficient way to warm your house in winter – it can also be used as an air conditioner in summer. Whole-home, ducted heat pump systems create an even temperature throughout and can be set with a thermostat for best efficiency. Briefly turning on the heat pump in the evenings to cool the bedrooms before bed can be enough to ensure a good night’s sleep.
- Install a ceiling fan- Set it to run counter-clockwise in the summer at a higher speed. The fan’s airflow will create a wind-chill breeze effect.
- Use exhaust fans-pull the hot, damp air from showers and cooking out of the house as soon as possible.
- Create an evaporative cooling effect in dry heat by placing a damp towel or mesh over an open window. Use a fan if no breeze is blowing. This only works if there is very little humidity in the air.
These same principles generally work in reverse in the winter time. To read more, click on "That She Blows: Wind and Heat Loss"