Appliance-aware sizing
How many solar panels do your appliances add?
Appliances do not each require a permanently dedicated panel. Their electricity use adds to the home's total energy target, and the solar array is sized against that combined annual consumption.
| Appliance or load | Watt My Roof planning allowance | Approximate annual equivalent |
|---|---|---|
| Refrigerator | 55 kWh/month | About 1–2 panels |
| Washer | 12 kWh/month | Less than 1 panel |
| Electric dryer | 75 kWh/month | About 2 panels |
| Central HVAC | 240 kWh/month | About 5 panels |
| Electric water heater | 320 kWh/month | About 7 panels |
| Electric vehicle | 260 kWh/month | About 6 panels |
| Pool pump | 300 kWh/month | About 7 panels |
How to add appliances to a solar estimate
- Find each appliance's energy use. Use measured or labeled kWh over time rather than relying only on the appliance's watt rating.
- Add the appliance use to the household total. Combine monthly appliance kWh with the home's other electricity use instead of assigning permanent panels to individual appliances.
- Estimate annual output per panel. Multiply panel kilowatts by local peak sun hours, 365 days and a realistic performance factor.
- Divide the annual load and round up. Divide annual electricity target by annual output per panel, round up and then verify roof, inverter and utility limits.
These are planning allowances, not appliance ratings
A label showing watts tells you instantaneous demand. Solar sizing needs energy over time: watts multiplied by operating hours. Climate, household habits, equipment efficiency and fuel type can move these examples sharply. Use the transparent solar calculation formula or calculate from your electric bill.
Solar panels are not the whole off-grid answer
If the goal is backup or off-grid power, panel energy alone is insufficient. You must also size an inverter for simultaneous and startup loads and a battery for the hours you want to operate without sunlight.
Frequently asked questions
How many solar panels does a refrigerator need?
A refrigerator using about 55 kWh per month represents roughly 1–2 modern 400-watt panels under this guide's five-sun-hour and 20%-loss assumptions. The panels serve the home's combined load rather than one dedicated appliance.
How many solar panels does an electric dryer add?
An electric dryer using about 75 kWh per month adds roughly two 400-watt panels under the guide assumptions. Real usage varies with household size, cycle frequency and dryer efficiency.
How many solar panels does central air conditioning add?
The Watt My Roof planning allowance of 240 kWh per month is equivalent to roughly five 400-watt panels. Climate, thermostat settings, equipment efficiency and seasonal operation can change that sharply.
Can solar panels run appliances at night or during an outage?
Panels do not directly cover nighttime or outage operation without the right grid connection or battery system. Backup planning also requires inverter and battery sizing for simultaneous, startup and overnight loads.