As previously stated, it is likely that your heating and air conditioning costs are higher than anything else in the home. That’s not always the case, but there is a good chance of it.
There are four factors that affect heating and cooling costs: the outdoor temperature; the thermal efficiency of your home (insulation); the efficiency of your heating and cooling system; and the temperature you want to maintain inside the home (thermostat setting).
There is nothing you can do that more effectively controls the cost of keeping your home comfortable than insulating it properly. That includes sufficient R-values of insulation in the attic, walls and floor, as well as buttoning up air leaks throughout the house. Keep in mind that attic insulation should be at least R-30, wall insulation at least R-12, and floor insulation at least R-19.
Now that things are well-insulated, look for holes in the walls, floor and ceiling, such as cracks around windows, doors, light fixtures, plumbing entrances and other assorted airways. All windows should be either the self-insulating type or should have storm windows installed. Around all windows and doors, close off small gaps with caulking or weather-stripping.
Refer to the following list of possibilities when looking for less conspicuous air leaks:
• Plumbing penetrations through insulated floors or ceilings
• Fireplace dampers
• Attic access hatches
• Recessed lights and fans in insulated ceilings
• Missing plaster
• Electrical outlets and switches, especially on exterior walls
• Window, door and baseboard molding
• Dropped ceilings above bathtubs and cabinets