I truly believe that caulk is wonderful, amazing thing to have and use in the home!! First, get your caulk and caulk gun. Caulk around all windows, inside and out. Include the facings, wood or brick. Around the frames also. Just this one step alone makes so much difference in keeping air both in and out.
Next, caulk around doors, inside the hot water heater closet, inside your air conditioning unit closet, holes under the sink around the pipes. If you have alot of openings in the closet where your air conditioning unit is, your air is escaping.
If you have any electrical outlets or light switches that do not have plate covers, get some. You would be amazed at how much air comes in around these holes.
If you have paneling and there are large spaces (cracks) between the sheets of paneling, caulk it. You can buy colored caulk. Or alot of people are painting paneling.
Close your blinds during the day if you aren’t at home. Especially in the summer and if the sun shines in the window. This will keep heat out. A darker house is a cooler house.
Close off any vents in rooms that you aren’t using.
Turn the temperature down some on your hot water heater. Do you know how much electricity it takes to heat up the water in the tank??
Wash clothes in cold or warm water if you can. This will cut down on the electricity it takes to heat the water.
Unplug everything not in use. Plug it back in when you need it. Everything that is plugged into an outlet is pulling electricity! You will be pleasantly surprised at how much the electric bill will go down.
Keep your central air unit on a consistent temperature. It takes more energy to cool down a house that has heated up all day or warm up a house that has been cold all day than it does to get it to a comfortable temp and leave it alone.
Go up into the attic and make sure that your duct work is properly sealed at the seams and no air is escaping. Also make sure that you have plenty of insulation.
In short, caulk up every crack or seam in the house. Putty every hole and then sand the putty down. Once you have all these places sealed, you will see a big difference in your energy costs and also how much more efficient the temperature control in the house will stay.