What you need to know
- Measure for long enough to capture normal cycling.
- Record both kWh and measurement duration.
- Plug-in meters are not suitable for every appliance or fixed circuit.
Use your own measurements
BricoDato tools help turn the guide into quantities, kWh, cost or a project plan.
Watts are not monthly consumption
Power tells you the rate of energy use at a moment. Monthly energy depends on how long the appliance runs and whether it cycles or changes load.
Measure a representative period
For fridges, dehumidifiers and other cycling loads, a short reading can mislead. Measure over a normal day or longer when practical.
Convert measured kWh into cost
Multiply the measured kWh by your effective energy price. If the measurement covers several days, divide by days before scaling to a month.
Respect meter limits
Check maximum current and power, earthing, plug type and manufacturer instructions. Do not use a plug-in meter on hard-wired appliances or loads beyond its rating.
Final check
Before buying material or doing the work, review the assumptions and technical limits that matter for your specific product, room or installation.
- Check the meter rating.
- Measure a normal usage period.
- Record kWh and time together.
- Do not use plug-in meters on incompatible or fixed loads.
Keep a small job sheet
Record the measurements, product reference, technical values you used, date and final result. For maintenance or diagnostics, also note the conditions at the time. A short written record makes future comparisons much more reliable.
Turn the guide into a decision
Use your measurements and the manufacturer’s technical data. If the decision affects fixed electrical work, structure, hidden leaks, refrigerant systems or another safety-critical installation, consult a qualified professional.