As with windows this will prevent drafts and energy loss. Check the insulation in your ceilings and walls. Homes without proper insulation use twice as much fuel to heat as a home with proper insulation. If your crawl space or basement is heated cover any opening with polyethylene film or use storm windows and doors. Windows should have ample coverings to provide shade from warm sunlight in summer months.
Draperies can provide added insulation in winter.
Avoid placing furniture over or in front of registers or air returns. This can affect your system's efficiency. Keep your garage door closed in winter and summer. In summer, avoid activities such as cooking or laundering during warmest periods of the day. Your system will work harder to keep your home cool.