How much electricity does a wax warmer use?

There is nothing clever here, and that is the point. Every energy figure on this site comes from this one line:

Annual cost = (rated watts ÷ 1000) × hours per day × 365 × cost per kWh

Worked through slowly, for a 25 W warmer at six hours a day and 17 cents per kilowatt-hour:

1. Watts to kilowatts. 25 ÷ 1000 = 0.025 kW.
2. Kilowatts to kilowatt-hours per day. 0.025 × 6 = 0.15 kWh a day.
3. Per year. 0.15 × 365 = 54.75 kWh.
4. To dollars. 54.75 × $0.17 = $9.31.

That is the whole method. If you want the number for your house, put your own rate in step four and your own hours in step two.

These are published figures, not estimates. Where a maker publishes nothing, we say so rather than borrowing a number from a lookalike product.

The most useful thing in that table is the first two rows. Those two warmers come from the same maker, are the same size and shape, and differ by a factor of 2.4 on rated power. You cannot tell them apart by looking. That is why a published wattage is the first thing we rank on in our warmer picks.

A useful sanity check, and one that cuts against selling you anything: none of these numbers is large.

At six hours a day, the entire annual electricity cost of the most power-hungry warmer we index is under ten dollars. The difference between the cheapest and the most expensive is about five dollars and sixty cents a year.

For comparison, at the same 17 cents per kilowatt-hour: a 1,500 W space heater costs about 25 cents an hour, so it passes the warmer's annual cost in about thirty-seven hours of use.

So the honest headline is: the electricity is not the expensive part. The wax is. If you want to spend less on this hobby, buy differently rather than running differently - see cost per hour of fragrance.

Where wattage does matter is at the extremes. A 25 W plug-in left running continuously, which happens because it is out of the way and easy to forget, is about $37 a year against $14.89 for a 10 W plate warmer at the same duty cycle. That is a real difference for a device doing an identical job.

A distinction the wattage table alone does not show.

In a bulb warmer the bulb is both the heat source and a light source. You are paying to illuminate the room whether or not you wanted light. In a plate warmer every watt goes into the dish.

That is why a 25 W bulb warmer does not necessarily throw 2.5 times as hard as a 10 W plate warmer despite drawing 2.5 times the power - some of that energy is leaving as visible light. Wattage is a rough proxy for throw, not a direct measure of it. See how wax warmers work.

There is also a consumable. A bulb warmer eventually needs a bulb, and that is a cost the electricity figure does not capture. Working through it on bulb replacement costs.

If you want to substitute a real rate rather than our assumption, your bill has the number on it - usually as a per-kWh charge, sometimes split into supply and delivery components that both need including.

Two things that catch people out. First, if you are on a time-of-use tariff the rate depends on when the warmer runs - evening use is often the expensive window, and evening is when a warmer runs. Second, a standing daily charge is not affected by the warmer at all, so exclude it.

Once you have your rate, the formula at the top of this page works unchanged. Multiply, and you have a number specific to your house rather than to our assumption - which is the whole point of publishing the method rather than just the answer.