Home heating advice you can actually trust.

A good rule of thumb is 10 watts of electric heat per square foot of floor space in an average, insulated room — so a 1,500-watt heater comfortably handles about 150 sq ft. Add 20–30% for high ceilings, poor insulation, a basement or a garage, and subtract if the room is already served by central heat.

Electric resistance heaters are 100% efficient at the unit but electricity usually costs more per unit of heat than natural gas, so gas is normally cheaper to run where a gas line already exists. Electric wins for a single room, for zoned use where you heat only the space you occupy, and when the alternative is running a whole central system.

The three usual causes are an undersized tank for the household, a failed lower heating element or thermostat, and sediment build-up that steals tank capacity. Our troubleshooting guides walk you through telling them apart in a few minutes with nothing more than a multimeter and a bucket.

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Many electric units are a genuine DIY job if you are comfortable with a breaker panel and can follow clearance requirements. Anything that involves gas piping, venting a combustion appliance, or altering a flue should be signed off by a licensed pro — the safety guides on this site tell you exactly where that line sits for each type.