Heat Loss via Drafts

You can lose a lot of heat through unwanted air currents (drafts). Warm air can leak out of your house under doors, through exhaust fans, up chimneys and through gaps around plumbing outlets. Heated air rises; air in contact with cold glass surfaces cools, becomes denser and falls. In this way an air current is set up, allowing heat to flow out of your living room via the windows, even when they're closed (see picture below). Heavy floor-length curtains with pelmets (or curtains touching the window-sills) will stop this current and keep your house warmer. In areas with cool or cold winters, blocking drafts is the most cost-effective way to make an existing house more comfortable. Seal gaps around poorly-fitting windows, add weather-strips to external doors and cover exhaust fans.

Airtight construction can also help on hot summer days in the temperate climates and the hot dry summer, cool winter climate. In these climates, your house stays cooler if you can shut out the hot air during the day. Open the doors and windows at night, to bring cooler air into your house.

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