10 easy ways to green your home

Upgrading the insulation in your home - including caulking and weather-stripping around windows and doors - can cut your heating bills by as much as 20%. (To learn how to do a home energy audit and find leaks, see energystar.gov.)

But you should also pay attention to design features that make insulation harder or easier.

Cathedral ceilings and flat roofs need extra attention
In homes with those features, your ceiling may sit directly under the roof, putting the room that much closer to the elements. You'll need to make sure these ceilings are especially well insulated and carefully vented.

Recessed lights can leak
After all, they basically require you to punch a lot of holes in your ceiling. If you install them under attics or roofs, make sure to use fixtures that are IC rated, which means you can safely pack insulation above and around them. These can cost $10 to $20 extra.

Dirt insulates
If the site where you intend to build your home is sloped, consider putting a portion of the structure underground. You'll get some natural protection against extremes of both heat and cold.

NEXT: ...but also ventilate and circulate