Home Power Facts How many solar panels to keep a load running every day
To keep a refrigerator (1,600 Wh a day) running on solar in Chicago, you need about 3 × 200 W panels on an average day and 5 in December, plus a power station that accepts at least 1,000 W of solar and stores enough for the night. The table covers 5 common loads in 8 US cities.
Number of 200 W panels needed, average day / December
| Load (energy a day) | Phoenix | Los Angeles | Denver | Miami | Dallas | Chicago | New York | Seattle |
|---|---|---|---|---|---|---|---|---|
| Refrigerator, all day1,600 Wh a day | 2 / 3 | 3 / 3 | 3 / 3 | 3 / 3 | 3 / 3 | 3 / 5 | 3 / 5 | 4 / 9 |
| Refrigerator + Wi-Fi router, all day1,960 Wh a day | 3 / 3 | 3 / 4 | 3 / 4 | 3 / 4 | 3 / 4 | 4 / 6 | 4 / 6 | 5 / 10 |
| CPAP with heated humidifier, 8 h a night720 Wh a day | 1 / 2 | 1 / 2 | 2 / 2 | 2 / 2 | 2 / 2 | 2 / 3 | 2 / 2 | 2 / 4 |
| CPAP without humidifier, 8 h a night360 Wh a day | 1 / 1 | 1 / 1 | 1 / 1 | 1 / 1 | 1 / 1 | 1 / 2 | 1 / 1 | 1 / 2 |
| Wi-Fi router / modem, all day360 Wh a day | 1 / 1 | 1 / 1 | 1 / 1 | 1 / 1 | 1 / 1 | 1 / 2 | 1 / 1 | 1 / 2 |
How this is calculated: panels = daily energy × 1.20 ÷ (200 W × 75% real-world = 150 W × the city's peak sun hours), rounded up. The 1.20 factor is rated ÷ usable capacity at the median of the 22 independently tested power stations: refilling the battery takes more energy than later comes out. Peak sun hours are NREL's annual average and December figures (solar assumptions). Loads: Refrigerator 66.7 W × 24 h; Refrigerator 66.7 W × 24 h + Wi-Fi router / modem 15 W × 24 h; CPAP with heated humidifier 90 W × 8 h; CPAP (no humidifier) 45 W × 8 h; Wi-Fi router / modem 15 W × 24 h. Not included: the station's own idle draw and runs of cloudy days, so treat these as a minimum. A panel's real output also depends on the station's input limits.
Power stations that accept enough solar
- Refrigerator, all day in a Chicago December needs at least 1,000 W of solar input and 1,600 Wh of usable battery. Lowest list price first: BLUETTI AC200L (1,200 W, $899), BLUETTI Elite 200 V2 (1,000 W, $899), EcoFlow DELTA 2 Max (1,000 W, $1,299), Jackery HomePower 3000 (1,000 W, $1,499), BLUETTI Apex 300 (2,400 W, $1,699), and 6 more.
- Refrigerator + Wi-Fi router, all day in a Chicago December needs at least 1,200 W of solar input and 1,960 Wh of usable battery. Lowest list price first: BLUETTI Apex 300 (2,400 W, $1,699), Anker SOLIX F3800 (2,400 W, $2,299.99), EcoFlow DELTA Pro 3 (2,600 W, $3,299), Jackery Explorer 5000 Plus (4,000 W, $3,499), Goal Zero Yeti PRO 4000 (3,000 W, $3,999.95), and 1 more.
- CPAP with heated humidifier, 8 h a night in a Chicago December needs at least 600 W of solar input and 720 Wh of usable battery. Lowest list price first: BLUETTI Elite 100 V2 (1,000 W, $499), Anker SOLIX C1000 (600 W, $599.99), Jackery Explorer 1000 Plus (800 W, $699), EcoFlow DELTA 3 Plus (1,000 W, $799), BLUETTI AC200L (1,200 W, $899), and 14 more.
- CPAP without humidifier, 8 h a night in a Chicago December needs at least 400 W of solar input and 360 Wh of usable battery. Lowest list price first: BLUETTI AC180 (500 W, $499), BLUETTI Elite 100 V2 (1,000 W, $499), Jackery Explorer 1000 v2 (400 W, $589), EcoFlow DELTA 3 Classic (500 W, $599), Anker SOLIX C1000 (600 W, $599.99), and 19 more.
- Wi-Fi router / modem, all day in a Chicago December needs at least 400 W of solar input and 360 Wh of usable battery. Lowest list price first: BLUETTI AC180 (500 W, $499), BLUETTI Elite 100 V2 (1,000 W, $499), Jackery Explorer 1000 v2 (400 W, $589), EcoFlow DELTA 3 Classic (500 W, $599), Anker SOLIX C1000 (600 W, $599.99), and 19 more.
Only stations that can run the load for a full day on one charge are listed, to cover the night and a cloudy day. Runtime by station: (fridge, CPAP). Panel compatibility for each station: solar panels.