How Many Watts Does a Campervan Use Per Day?
Understanding your campervan's daily power consumption is the foundation of sizing the battery and solar system correctly. Most van lifers use between 400Wh and 1,500Wh per day, with the fridge and inverter appliances being the biggest variables.
Average campervan daily consumption by lifestyle
| Lifestyle | Typical daily consumption | Equivalent |
|---|---|---|
| Basic (fridge, lights, phone) | 400–600Wh | 33–50Ah at 12V |
| Moderate (above + laptop, fan) | 700–1,000Wh | 58–83Ah at 12V |
| Comfortable (above + kettle, induction) | 1,000–1,500Wh | 83–125Ah at 12V |
| High (above + work setup, coffee machine) | 1,500–2,500Wh | 125–208Ah at 12V |
Breakdown by appliance
The compressor fridge: biggest steady consumer
A quality 50L compressor fridge (Dometic CFX, Engel, Brass Monkey) draws 30–50W when the compressor runs, but averages 20–40W over 24 hours because the compressor cycles.
Daily fridge consumption:
- Cool UK climate (15°C ambient): 20W average × 24h = 480Wh/day
- Warm summer (25°C ambient): 35W average × 24h = 840Wh/day
- Very hot conditions (35°C ambient): 50W+ average × 24h = 1,200Wh/day
The fridge is almost always the largest single consumer — 40–60% of total daily consumption in most builds.
Lighting: much less than most people expect
LED lighting in a van uses very little energy:
- 10 LED strip segments (equivalent to reasonable interior lighting) = 20–30W total
- Used for 4 hours in the evening: 25W × 4h = 100Wh/day
Switching from halogens or filament bulbs to LED dramatically reduces lighting consumption.
Kettle and cooking
A 750W travel kettle boiling once for 3 minutes:
- 750W × 0.05h = 37.5Wh per boil
- 5 boils per day (breakfast, coffee × 4) = 190Wh/day
An induction hob on a 20-minute cook:
- 1,000W × 0.33h = 330Wh per cooking session
- Two cooking sessions per day = 660Wh/day
Cooking via inverter is a significant consumer. Gas cooking eliminates this entirely — many van lifers use a 2-burner LPG stove for cooking and only use the induction hob occasionally.
Laptop and work
A 13" laptop (45W charger) used for 8 hours:
- 45W × 8h = 360Wh/day
A 15" laptop (65W charger) + external monitor:
- 65W + 20W × 8h = 680Wh/day
Remote workers should include full laptop usage in their calculations.
Phone and device charging
Charging two smartphones + a tablet:
- ~20W average × 3h = 60Wh/day
Small — but every bit counts.
How to reduce consumption
Fridge first: The fridge is worth targeting because it runs 24/7.
- A well-insulated fridge uses 30% less than a poorly insulated one. Avoid placing in direct sun.
- Keep the fridge at 4–7°C, not colder.
- Pre-cool food and drinks before putting them in.
Cook on gas: Switching 30 minutes of induction cooking to LPG saves 500–800Wh/day.
Prioritise 12V over 230V: Devices running directly on 12V (12V fridge, 12V TV, USB charging) are more efficient than running via an inverter (230V device from battery). The inverter adds 5–15% conversion loss.
LED lighting is already efficient — no further savings needed here.
Laptop power settings: Reducing screen brightness and enabling power-saving modes can reduce laptop draw from 65W to 35W — saving 240Wh over 8 hours.
Calculating your personal usage
Rather than using averages, calculate your specific setup:
- For each appliance: watts × hours/day = Wh/day
- Sum all Wh/day values = total daily consumption
- Divide by 12 = daily Ah consumption at 12V
Then size your battery for at least 1.5× the daily Ah at 90% usable DoD (for LiFePO4), and size your solar to match daily consumption.
FAQ
How much power does a diesel heater use?
A diesel heater (Webasto, Eberspacher, or Chinese diesel heater) draws 8–12W when running on its 12V electrical supply. Running all night (8 hours): 10W × 8h = 80Wh — modest. The main fuel cost is the diesel itself, not the electricity.
Does a 12V fridge use less than a 230V fridge via inverter?
Yes. A 12V compressor fridge (e.g., Dometic CFX) runs directly on 12V DC — no conversion loss. Running the same fridge through an inverter adds 5–15% energy overhead. More importantly, a 12V fridge does not create the large inverter startup surge that a 230V fridge would.
How do I measure my actual consumption?
Install a battery monitor with a shunt (Victron BMV-712 or SmartShunt). This records cumulative energy in and out. After a day of normal use, the monitor shows exactly how many Ah (and Wh) you consumed. Far more accurate than estimates.