Guide 10 / 10
Check an 'energy-saving' product claim
Ask a few concrete questions before relying on a percentage without a clear baseline.
Ask what it is compared with
A '40% more efficient' claim needs a named comparison product, equivalent service, and test conditions. Lamps should deliver comparable light; automated appliances need comparable settings and conditions. A percentage with no baseline is not enough to predict your bill.
Find the unit and period
Does the claim refer to watts while active, kWh per year, energy cost, or total ownership cost? These are different questions. If an official energy label is available, read its kWh and test conditions. The price and electricity rate in an advertisement may differ from yours.
Recalculate with your inputs
Enter your watts, hours, days, quantity, and rate in the comparison tool. Look at the kWh difference first; cost is only an estimate based on the rate you enter. If measured power is unavailable, label the comparison as illustrative and avoid an expensive decision based on one number.