Practical guide
How to Estimate Daily RV Electricity Use
Start here if you know which devices you use but do not yet know your daily watt-hours. You will build a device list, then use its battery-powered totals in the planning tools.
Have watts and running hours? Start here.
For the running-watts input, gather:
- Each device’s running input watts from its label, manual or a measurement.
- How many of each device you use and how many hours each one actually runs per day.
- Its power source: direct battery DC, AC through an inverter, or another source.
Use electrical input watts, not cooking output. For cycling devices, count time actually running, not all the hours switched on.
Start with my devicesIf your label does not show watts, or you are unsure about any input, keep reading for the other ways to enter your numbers.
1. Find the number you actually have
Look at the device label, its manual, an energy label, or a suitable power-meter reading. Choose the matching input type in Daily Power Consumption.
- Watts (W): running input power. For a microwave, use electrical input power, not cooking output.
- DC volts and amps: the voltage and running current of a DC device.
- AC volts and amps: also requires power factor (PF). Volts × amps alone is VA, not necessarily real watts.
- kWh/day or kWh/year: already includes time. Do not multiply it by running hours again.
If you only have AC volts and amps but no PF, find documented real input watts or a suitable measurement. The tool does not infer PF from the appliance name. If you cannot find a required number, leave it blank until you can verify it rather than guessing. The calculator needs that value to produce a valid total.
2. Estimate how long each device actually runs
For W or V/A inputs, enter the number of hours the device actually runs on a representative day. A light on for four hours uses four running hours. A cycling fridge or pump does not necessarily run for all the hours it is switched on.
Use a representative measurement where possible. The power shown on a label may be a rating rather than average consumption. For an annual kWh label, the tool divides by 365; this is an average under the label’s conditions, not a prediction for your trip.
3. Tell the tool where the power comes from
The number on a label does not tell the calculator how the device is connected in your RV. Choose its source separately:
- Direct DC from battery: supplied by the battery system without an AC inverter.
- AC through battery inverter: an AC device getting power from the battery through an inverter.
- Other source: a device supplied only by shore power or a generator in this scenario.
If the source changes between trips, make the list for the scenario you are checking. If you are not sure yet, leave it as “Not specified yet” until you can verify it. Assign a power source to every device before transferring the totals.
4. Read and reuse the totals
A device using 60 W for two hours consumes 120 Wh/day. Two identical devices consume 240 Wh/day. These are arithmetic examples, not suggested appliance values.
The result shows energy at the devices. The AC subtotal has not yet had inverter losses added. Once every device has a power source assigned and there is some battery-powered energy use, choose Battery Size, Solar Size or System Checker to transfer the DC and AC subtotals. Keep them separate; do not put the whole total in both fields.
Only those two totals are passed to the next calculator; your device list is not. Review them on the next page and enter the remaining values and assumptions.
What this does not tell you
Wh/day measures energy over time. It does not show whether an inverter can start a motor or whether several devices can run at once. For that, follow the power-source guide. For capacity and daily solar estimates, continue to the battery and solar guide.
The calculator excludes unlisted devices, startup surge and separately modeled inverter idle or wiring losses. Each calculator’s method explains its own scope and sources.