Energy efficiency and conservation are the least-cost energy option and an essential complement to renewable energy. If you're just starting to explore your clean energy options, start with efficiency and conservation - it usually costs less to save a kilowatt-hour than to produce it!
Here are some tips and links to further information.
INSULATION - a huge saver. Note - many run-of-the-mill general contractors / carpenters are not entirely up to speed on proper installation of insulation. There's a lot of science to it. Check manufacturer's websites and data pages. Learn what a vapor barrier is. Know how moisture damage can occur if insulation is improperly installed (usually when warm moist air contacts a cold surface in an area of little or no ventilation). EnergyStar Insulation Information. Energy Star DIY. Basement vapor barrier Bathroom vapor barriers Attic vapor barrier and ventilation
PROGRAMMABLE THERMOSTATS - another big "bang for the buck." Available at home improvement stores for between $20 and $60, depending upon features. Work with central heat and air-conditioning systems. Not really for baseboard electric heat. Programmable thermostats that work with heat pumps are different than those for non-heat pump systems, - you'll find both in the same place. The heat-pump ones will just have a couple extra wires. Usually can "do it yourself" - remove existing thermostat slowly and carefully and note how wires are hooked up so you can hook up the same way on new thermostat. Shut your HVAC off at 9:00 am after you've gone to work; have it kick back on at 4:30 to make the home comfortable before you get home. Save a LOT OF MONEY. EnergyStar Programmable Thermostat Info.
LED AND CFL BULBS - more expensive than incandescent up front. Save a fortune in the long run. LEDs last a long long time - excellent to install in hard to access places, like a light fixture high in a vaulted ceiling. Some say they work with dimmers. We don't know how good they are. Might want to use low watt bulbs in some places / on some circuits for dimming effect. You get what you pay for with LED bulbs, also.
AIR DUCT SEALING - inexpensive possible do-it-yourself project. Note (and this may sound crazy) DO NOT use "duct tape." Most types degenerate in a relatively short time into a shredded, leaky mess. Use aluminum tape or use air duct sealing compound in a caulk gun.
SOLAR POWERED CLOTHES DRYERS - huge energy savings. Note - you can also hang hooks in various rooms in the house, and dry clothes on the hooks - kids' clothes in kids room, etc. Many of the nicest homes in European countries have no electric clothes dryer - they have places within the living space to hang clothes.
INSULATED SWITCH AND OUTLET COVERS, especially on outside walls (Home Depot, Lowes, Amazon, True Value etc). Inexpensive and easy.
WINDOWS - often an expensive fix, but if you have old drafty windows, you will also be buying increased comfort in your living space, as well as energy savings. Also, most buildings have large gaps around the windows, behind the trim, that allow drafts to come through.
DOORS - same comments as windows
INSULATE RIM JOISTS - (the outside of your basement walls, just under the first floor). Some say to use spray foam or foam board, but that can lead to undetectable moisture problems. You can also use batts of fiberglass insulation wrapped in plastic bags, the whole thing large enough to seal the joist space (see picture to left).
NEW CONSTRUCTION - Energy Star new home guidelines (30% energy use reduction, okay, but not nearly as good as PassiveHaus guidelines). Money invested on the front end pays for decades on the back end.
Note that the new Richardson Elementary School near Bowling Green uses only 20 - 25% of the "average" school. New homes in Germany (often small and incredibly well-insulated) are sometimes adequately heated by BTUs coming off of the occupants' bodies.