Install an Energy Star programmable thermostat for $60 to turn down the heat when you sleep and raise it in the morning. (This makes climbing out of bed easier too.)
Be sure to change the air filter in your heating and cooling system at least every three months.
With 1 in 4 homeowners underwater, many pundits predict a flood of people walking away from their homes. 5 readers discuss why they are - and are not - sticking around. More