Home Energy Audit Savings Calculator

Enter your average monthly electric bill and your average monthly heating bill for gas, oil or propane. If you heat with electricity, enter $0 for heating and include it in the electric bill. Then choose the home's age band.

Worked example: $150 electric, $100 heating, built before 1980. Annual spend = ($150 + $100) × 12 = $3,000. The breakdown is:

• Heating and cooling: $1,560
• Water heating, lighting and refrigeration: $750
• Other devices: $690

The pre-1980 band uses a 20% typical savings rate, giving $600 a year, within a range of $150 (5%) to $900 (30%).

Use monthly averages across a full year, not a single winter bill. If you enter a January heating bill as the monthly average, the calculator multiplies a peak month by twelve, which overstates annual spend and every figure that follows.

Annual energy spend = (Monthly electric bill + Monthly heating bill) × 12.

Category costs = Annual spend × 0.52 for heating and cooling, × 0.25 for water heating, lighting and refrigeration, and × 0.23 for other devices.

Low estimate = Annual spend × 0.05. High estimate = Annual spend × 0.30. The range is the Department of Energy's Energy Saver estimate of potential savings from reducing drafts, 5% to 30% a year, used here as a band for audit-led improvements.

Typical estimate = Annual spend × the age-band midpoint: 0.20 before 1980, 0.15 for 1980 to 2000, and 0.10 after 2000. These midpoints are the calculator's own assumption, not a measured figure. They reflect that older homes usually have less insulation and more air leakage than homes built to newer energy codes.

The savings percentage is applied to the whole bill, not to each category separately.

Now take a home built in the 1990s with a heat pump and no gas service. Bills average $230 a month, all electric, so heating is $0.

Annual spend is $2,760. The breakdown is $1,435.20 for heating and cooling, $690 for water heating, lighting and refrigeration, and $634.80 for other devices. The 1980 to 2000 band uses a 15% typical rate, so the estimate is $414 a year, within a range of $138 to $828.

A third profile, a post-2000 home paying $120 for electricity and $60 for heating, spends $2,160 a year. At the 10% rate its typical estimate is $216, with a range of $108 to $648.

Across the three homes, the typical savings fall from $600 to $414 to $216. Part of that drop is the smaller bill, and part is the age band. Put the post-2000 home in the pre-1980 band and its typical estimate would be $432. The newer home's 10% rate halves that, on the assumption that it has less left to fix. The low and high ends ignore age and move only with spend.

This page is the umbrella. It shows where the money goes. The next step is to price real fixes in the largest slice.

Heating and cooling (52%): start with the building envelope. The insulation R-value calculator uses heat-loss physics, from area, R-values and heating degree days, to price a specific insulation upgrade. The home insulation savings calculator works from your heating and cooling bill and adds install cost and payback. For controls and equipment, the smart thermostat savings calculator prices temperature setbacks, and the heat pump savings calculator compares heating systems.

Water heating, lighting and refrigeration (25%): the LED bulb savings calculator covers lighting. The Energy Star appliance savings calculator compares a standard and an efficient refrigerator from their EnergyGuide kWh figures.

Other devices (23%): the appliance energy calculator prices any device from watts and hours, and the vampire power drain calculator finds standby loads.

Common mistake: chasing the smallest slice first because the fixes are cheap. Swapping bulbs is fast, but lighting sits inside the 25% slice alongside water heating and refrigeration. For most homes, air sealing and insulation in the 52% slice decide how much the bill can move.

The 52/25/23 split is a national average of energy use across US homes in all climates. Your own split depends on climate, home size, number of occupants and heating fuel. A mild coastal home has a much smaller heating slice than one in a cold northern state.

The shares measure energy use, but the calculator applies them to dollars. In a home heated with gas, electricity usually costs more per unit of energy, so the dollar share of lighting and appliances can be higher than the energy share.

The 5% to 30% band and the age midpoints are not a guarantee. A home that already has recent insulation and air sealing may save less than 5%. A very leaky home may save more than 30%.

The calculator does not include the cost of the audit or of the fixes it recommends, so it cannot give a return on investment. Only an on-site assessment with a blower-door test and a room-by-room inspection can find your home's actual problems.

Once this page shows where the money goes, price the biggest slice first. For walls and attics, use the insulation R-value calculator, or the home insulation savings calculator if you want payback on an installed cost. For controls, the smart thermostat savings calculator shows what setbacks are worth.

When an appliance is due for replacement, the Energy Star appliance savings calculator tests whether the efficient model's premium pays back. The appliance energy calculator shows what the devices you already own cost to run.