Understanding Energy Use in Your All-Electric Home

If you plan to improve your home's efficiency, it begin by understanding where you use electrical power.

The first step in understanding your electricity usage is to separate your annual electricity consumption into heating, air conditioning, and baseload uses. Baseload uses include water heating, lighting, refrigeration, laundry, and other uses that don't vary much from month to month. Once you have an estimate of your baseload usage, you can estimate your heating and cooling costs.

Look at your spring or fall electrical bills to estimate your baseload energy use, since you probably use little or no heating or air conditioning during this time. This is usually the months of April and May, or September and October. Calculate the average monthly electricity usage for these months in kilowatt-hours (kWh) to get a rough estimate of your monthly baseload. Then multiply this monthly baseload by 12 to estimate your annual baseload in kilowatt-hours.

To compute cooling electricity, subtract your average monthly baseload from the kilowatt-hours used for each summer month. For heating electricity, subtract the monthly baseload from the kilowatt-hours used each winter month.

The table below shows typical yearly electric consumption for 1600 square-foot homes in the Northern homes and Southern homes. If your home is much larger or smaller than the 1600 square feet used in these examples, the column labeled kWh/ft2 will help you rate your home on a per-square-foot basis.

Your baseload electrical consumption can be effected by older inefficient appliances, a high demand for hot water, or luxury loads such as spas and swimming pools.
Your electrical heating consumption depends on insulation levels, air leakage and heating efficiency.
Your air-conditioning electricity usage is determined by window shading, attic insulation, air leakage, and air-conditioning efficiency.

	Northern climates			Southern climates
Type of Use	Annual kWh	%	kWh/ft2	Annual kWh	%	kWh/ft2
Baseload	11,000	57%	6.9	9,650	63%	6.0
Heating	7,335	38%	4.6	3370	22%	2.1
Air Conditioning	965	5%	0.6	2300	15%	1.4
Total	19,300	100%	12.1	15,320	100%	9.5
From the Energy Information Administration and various utility companies. kWh = kilowatt hours

Once you understand how your home uses energy, you can go to work installing energy efficiency measures.

The Homeowners Handbook to Energy Efficiency contains simple, practical energy-efficiency ideas.