Home Energy Audit Calculator

What's eating your electricity? Enter your appliances and HVAC details — see your top energy consumers and monthly cost breakdown instantly.

tons
hrs/day
months
hrs/day
months
kWh/day
hrs/day
W
hrs/day
cycles/wk
loads/wk
loads/wk
hrs/day
hrs/day
$/kWh
Full home energy audit
5,232 kWh/year
Monthly usage436 kWh/month
Monthly cost$65/month
Annual cost$785/year
TOP CONSUMERS (kWh/month)
HVAC (cooling/heating)180.9 kWh (41%)
Clothes dryer100.0 kWh (23%)
Lighting45.0 kWh (10%)
Oven/range36.0 kWh (8%)
Computer30.0 kWh (7%)
Washer14.0 kWh (3%)
Water heater12.0 kWh (3%)
TV & entertainment9.6 kWh (2%)
Dishwasher8.4 kWh (2%)
Refrigerator0.1 kWh (0%)
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How to Use This Calculator

Start with HVAC — your biggest load

HVAC (heating and cooling) typically accounts for 40–60% of a home's electricity use. Select your heating and cooling system type, enter AC capacity in tons, and specify how many hours/day and months/year each system runs. If you have a gas furnace, only your AC uses electricity — heating won't appear on your electric bill.

Water heater

Enter your electric water heater's daily kWh. A standard 50-gallon electric water heater uses about 12–15 kWh/day for a family of 4. If you have a heat pump water heater, enter 3–5 kWh/day. Gas water heater? Enter 0 — it doesn't use electricity.

Appliances and lighting

Dryers, refrigerators, and dishwashers are the biggest electric appliances. The dryer is often the single largest appliance at 5 kWh per load. Adjust each input to match your household habits. Loads per week and hours per day convert to monthly kWh automatically.

Insulation quality

Insulation quality adjusts your HVAC estimate up or down. A poorly insulated pre-1980 home may use 30% more energy for the same indoor temperature than a well-insulated modern home. This is a rough correction — real-world variation depends on home size, window area, and local climate.

How the Calculator Works

HVAC (AC): Tons × 3.517 kW/ton ÷ SEER-approx × hrs/day × cooling months ÷ 12 HVAC (heat pump): COP 3 for cooling, COP 2.5 for heating Fridge: 0.15 kW × hrs/day × 30 days Dryer: 5 kWh/load × loads/week × 4 weeks Washer: 0.5 kWh/load × loads/week × 4 weeks Lighting: watts × hrs/day × 30 days ÷ 1000 Insulation factor: HVAC kWh ÷ insulation factor (0.85–1.3)

Results are estimates based on typical appliance power ratings. Real consumption varies by appliance age, efficiency rating, thermostat settings, and usage habits. For exact numbers, check your utility's hourly data portal or install a whole-home energy monitor.

Example: Average American Home

3-bedroom, family of 4, Southeast US, gas furnace + 3-ton AC

HVAC typeGas furnace + AC
AC capacity3 tons
AC usage8 hrs/day, 5 months
Water heater12 kWh/day
Dryer5 loads/week
InsulationAverage (1980s)

Top consumers by category

HVAC (cooling)~350 kWh/month
Water heater~360 kWh/month
Clothes dryer~100 kWh/month
Lighting~45 kWh/month
Refrigerator~108 kWh/month
Total~1,050 kWh/month

Water heater and AC/HVAC dominate. Switching to a heat pump water heater (saves ~200 kWh/month) and improving insulation or thermostat settings would have the biggest impact on this home's electricity bill — and on the solar system size needed.

How to Reduce Each Major Load

HVAC (biggest opportunity)

Set thermostats to 78°F cooling / 68°F heating. Use programmable or smart thermostats to reduce runtime when away. Seal air leaks around windows and doors. Add attic insulation. Consider upgrading to a heat pump — modern units are 3x more efficient than electric resistance.

Water heater

Lower temperature to 120°F (saves 10–15%). Install a heat pump water heater (saves 60–70% vs electric resistance). Add an insulating blanket to older tanks. Use timers to heat water during off-peak hours if on TOU rates.

Clothes dryer

Clean the lint filter every load (improves airflow = faster drying = less energy). Air dry when possible. Dry full loads. A heat pump dryer uses 50% less energy than a resistance dryer — worth considering at replacement time.

Lighting

If you haven't switched to LED yet, doing so cuts lighting energy by 75%. Use daylight sensors and timers for outdoor lights. Smart bulbs let you dim and schedule lighting automatically.

FAQ

Accuracy is within 10–25% for most homes. HVAC is the hardest to estimate precisely — it depends on home size, local climate, thermostat settings, and duct efficiency. The calculator uses national average appliance power ratings and typical usage patterns. For exact numbers, compare results to your actual utility bills, or use a whole-home energy monitor (Sense, Emporia Vue) for real-time tracking.
The US EIA reports an average of 877 kWh/month (10,500 kWh/year) for residential customers. This varies significantly: Louisiana averages 1,200+ kWh/month due to AC; California averages 550 kWh/month due to mild climate and efficiency standards. Homes with electric vehicles add 300–600 kWh/month depending on driving.
Yes — the annual kWh total from this audit is the input for solar panel sizing. Take your annual kWh from this calculator and enter it directly into the Solar Panel Calculator (along with your electricity rate and peak sun hours) to get panel count and system size. The audit also shows which loads to consider shifting to solar hours (running dishwasher and EV charging midday) to maximize self-consumption.

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