Appliance Energy Calculator

Check your appliances, adjust hours — get monthly kWh, cost by category, and solar size to offset.

How to Use This Calculator

Check or uncheck appliances

The calculator pre-selects the most common home appliances. Check the ones you have; uncheck the ones you don't. Each appliance shows default watt and hours-per-day values — adjust these to match your actual usage. The monthly cost updates instantly for every change.

Six categories

Appliances are organized into six categories: Kitchen (fridge, oven, dishwasher), Climate (AC, heating, fans), Laundry (washer, dryer, water heater), Entertainment (TV, computers, phone), Lighting, and Other (pool pump, EV charger, hot tub). Click a category header to expand or collapse it.

Adjust watts and hours

The default wattages are averages — your actual appliances may differ. For the most accurate results, check the label on each appliance or measure with a Kill-A-Watt meter (available for $25-30). Hours per day is how long you actually run the appliance — not its maximum run time.

Solar system size to offset all usage

The result includes a solar system size recommendation to offset all selected loads at 4.5 peak sun hours (the US average). Use the Solar Panel Calculator for a location-specific calculation using your exact peak sun hours.

The Formula

Daily kWh per appliance = Watts × Hours/day ÷ 1,000 Total Daily kWh = Sum of all enabled appliances Monthly kWh = Total Daily kWh × 30 Monthly Bill = Monthly kWh × Electricity Rate Annual Bill = Monthly Bill × 12 Solar System Size = Total Daily kWh ÷ Peak Sun Hours ÷ 0.86

Example

Average 3-bedroom home — Charlotte, NC

A typical 3BR home in Charlotte with central AC, electric water heater, electric dryer, standard kitchen, and LED lighting throughout.

Climate (AC + heat)14.0 kWh/day — 46%

Laundry (W/D + water heater)6.8 kWh/day — 22%

Kitchen4.2 kWh/day — 14%

Entertainment3.5 kWh/day — 11%

Lighting + Other2.2 kWh/day — 7%

Total30.7 kWh/day = 921 kWh/month

At $0.13/kWh (Charlotte average), this home pays $120/month in electricity. A 7.9 kW solar system at Charlotte's 4.7 peak sun hours would offset this usage entirely. Key insight: switching to a heat pump water heater would cut daily usage by 5.5 kWh, reducing the needed solar system by over 1 kW.

FAQ

What uses the most electricity in a home? ▼

In a typical US home: HVAC (40-50%), water heating (14-18%), washer/dryer combined (5-8%), refrigerator (3-5%), lighting (3-4%), electronics/computers (3-4%). Everything else is less than 1% each. The highest-impact efficiency upgrades target the top two: heat pump HVAC and heat pump water heater. Together they can cut a typical home's energy use by 30-40%.

How do I find the wattage of an appliance? ▼

Three ways: (1) Check the label on the appliance — usually on the back or bottom, shows watts (W) or amps (A) × volts (V) = watts. (2) Look up the model number online — manufacturer specs list power consumption. (3) Measure with a Kill-A-Watt meter plugged between the appliance and outlet — most accurate for variable-load appliances like refrigerators and computers. Note: watts on the label is peak draw, not average draw for cycling appliances like fridges.

How much electricity does a central AC use per month? ▼

A typical 3-ton central AC (3,500W) running 4 hours/day uses 14 kWh/day = 420 kWh/month = about $63/month at $0.15/kWh. In a hot climate (Phoenix, Houston) running 8-10 hours/day in summer: 840-1,050 kWh/month = $126-$158/month. Modern heat pump systems use 50-70% less energy than older resistance heating systems and 30-40% less than standard compressor AC.

Should I reduce energy use before installing solar? ▼

Yes — every kWh you eliminate reduces the solar system size you need. The hierarchy: (1) Attic insulation and air sealing (cheapest kWh reduction). (2) Heat pump water heater (~$1,500, saves 60-70% on water heating). (3) LED lighting if not done already. (4) Smart thermostat ($150, saves 10-15% on HVAC). (5) Heat pump HVAC (when replacing anyway). Focus on these before sizing solar — you may need a smaller, cheaper system.

How much electricity does an EV add to my home? ▼

On a Level 2 charger (7,200W), charging 2 hours per day adds 14.4 kWh/day = 432 kWh/month — roughly 40-50% more than a typical home without EV. This can increase your electricity bill by $50-$80/month and adds 2-3 kW to your solar needs. Many EV owners install solar specifically to offset charging costs, achieving "fuel" costs equivalent to $0.01-0.02/mile compared to $0.10-0.15/mile for gasoline.