What the appliances you use most cost to run, worked out from the label or a meter reading at your own rate.
Every guide in this section uses the same arithmetic as the calculator: watts from the label, or kWh from a plug-in meter, times your own rate. The worked examples are labelled with where their inputs came from. None of them is a measurement of your appliance, which is why each guide also says how to take one, and when a plug-in meter cannot.
Why a fridge's label watts overstate its use, how to read the EnergyGuide kWh figure, and how to measure it safely.
Read the guideRated watts versus real cycling, why humidity and room conditions change the answer, and how to get a measured figure.
Read the guideHow to measure an old freezer, what a replacement scenario needs to include, and why not every old freezer should be replaced.
Read the guideElectric, heat-pump and gas dryers compared per load, why a plug-in meter cannot measure a 240 V dryer, and the free changes that cut cost.
Read the guideThe arithmetic for a 1,500 W heater, why a low setting changes heat output not efficiency, and the CPSC direct-to-wall rule.
Read the guideWhat has to be true about your schedule, heating system and wiring before a smart thermostat pays back, without a manufacturer's headline percentage.
Read the guideStart with the two numbers every bill prints, then price the one appliance you suspect. Both tools show their arithmetic and keep everything in your browser.