Side by side
| 12V compressor fridge | Residential fridge | |
|---|---|---|
| Runs on | The 12V battery directly | 120V, through an inverter |
| Power a day | about 0.6 kWh (Dometic CFX3 55IM, rated) | about 1–2 kWh, plus 0.2–0.3 kWh for the inverter staying on |
| Size | coolers and small uprights, up to about 10 cu ft | up to about 18 cu ft and more |
| To start | a small start-up draw | about 1,200 W for a moment |
| Cost | several times a household fridge of the same size | cheap, sold everywhere, easy to replace |
The hidden cost: the inverter that never sleeps
A fridge cycles on and off day and night, so the inverter feeding it can never switch off. Victron's own datasheet puts a MultiPlus-II 3000 at 13 W with nothing plugged in, 9 W in its power-saving mode. Thirteen watts for 24 hours is about 0.3 kWh a day, half of what the whole 12V fridge uses.
If your inverter is on all day anyway (outlets, Starlink, a residential layout), that cost is already paid, and the home fridge only adds its own 1–2 kWh.
What each one needs from your solar
Using the guides' 0.77 for losses:
| Per day | Panels, summer (5 sun hours) | Panels, winter (3 sun hours) | |
|---|---|---|---|
| 12V fridge | 0.6 kWh | about 160 W | about 260 W |
| Residential fridge + inverter | 1.2–2.3 kWh | about 310–600 W | about 520–1,000 W |
On a van roof that fits two or three panels, that difference decides it. See what size solar panel for a van or RV.
Which one
- Van or small camper: 12V. The roof and battery space are the limit, and it runs even with the inverter off.
- Big RV, bus or skoolie: either. A residential fridge is bigger and far cheaper if you have the roof for about 600 W or more and the inverter is on anyway.
- Off-grid cabin or home: residential. The inverter is always on, the system is 48V, and the off-grid home guide already sizes for a full-size fridge.
How long a battery runs a home fridge: refrigerator on solar.
Questions people ask
Is a 12V fridge more efficient than a residential fridge?
Per day, usually. Dometic rates its CFX3 55IM at 0.59 kWh a day, while a full-size home fridge uses about 1–2 kWh. The home fridge also needs an inverter switched on around the clock; a Victron MultiPlus-II 3000 draws 13 W just being on, about 0.3 kWh a day. A home fridge holds far more food, though, so per cubic foot the gap is smaller.
Can I run a residential fridge on solar in an RV?
Yes, with enough battery and panels. Plan for about 1.2–2.3 kWh a day including the inverter, which is roughly 500–1,000 W of panels in winter sun and one to two 12V 100Ah lithium batteries for each day without sun. The inverter also has to start the compressor, which can take about 1,200 W for a moment.
How much solar do I need for a 12V fridge?
At about 0.6 kWh a day, roughly 260 W of panels in 3-sun-hour winter weather (0.6 kWh ÷ 3 hours ÷ 0.77 for losses), or about 160 W in summer.
Do 12V fridges cost more?
Yes. A 12V compressor fridge typically costs several times what a similar-sized household fridge does. In a van the battery and panels it saves usually pay that back; in a big rig with plenty of roof, the cheaper home fridge often makes more sense.
Sources
- Dometic CFX3 55IM specifications (0.59 kWh/24h; 1.11 Ah/h at 32 °C) Dometic
- MultiPlus-II inverter/charger datasheet (zero-load power 13 W, AES mode 9 W) Victron Energy
- 12V fridge in an RV: smart move or overhyped trend? (sizes, prices) Mortons on the Move
- Estimating appliance and home electronic energy use US Department of Energy
Every number on this page comes from these sources. Spotted something out of date? Tell me.
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