Heat pump

What a heat pump is

A conventional electric water heater has a resistance element that turns every kWh into heat, one for one. A heat pump uses a compressor and refrigerant to capture heat that already exists in the air and concentrate it in the tank. For every kWh it consumes, it delivers several times that amount as heat. It is the same machine as your air conditioner, running backward.

The unit needs air around it to draw heat from, and as a side effect it slightly cools and dehumidifies the space where it sits. That is why placement matters.

Why it matters in Florida

After air conditioning, the water heater is one of the largest energy users in a Florida home. And here the heat pump has the ideal setting: the garage or laundry room is warm nearly all year, so there is plenty of heat to extract. The side effect of cooling and drying that space is welcome, not a problem as it is in cold climates.

In air conditioning mode, a heat pump for space conditioning works like a conventional AC in summer and, on the few cold days, heats the house without the electric resistance strip that spikes the January bill.

Common mistake

Installing it in a closed closet with no ventilation. The unit needs air volume to work; boxed in, it loses efficiency and may fall back to resistance mode, which consumes like the old heater. The other mistake is comparing purchase price only: it costs more than a conventional heater, and the difference is recovered through monthly consumption, so you need to run the numbers for your home. More in heat pump water heater.