Types of Water Heaters

Choose a water heater by how it supplies hot water, how it heats water, and whether it fits your home. Tank, tankless, gas and electric are overlapping categories. A heat-pump water heater normally stores water in a tank and uses electricity; a tankless model can use gas or electric resistance.

This guide covers domestic hot water for showers, sinks and household appliances. A heat-pump water heater is a water-heating appliance; it is not the equipment selected to heat and cool your rooms.

Read the categories correctly

DOE explains the distinction between heat-pump and resistance water heating: the heat pump transfers surrounding heat into stored water, while an integrated unit may also include resistance elements. DOE Building Science Education.

Make a shortlist before choosing a model

First, photograph the existing heater's label, connections and installation location. Record what works: enough showers, acceptable waiting time, manageable noise. Record what fails: running out after a bath, high bills, repeated repairs, or an awkward location. These are different problems and may require different solutions.

Second, establish demand. Use tank sizing for storage equipment or tankless GPM for on-demand equipment. The size calculator helps record a planning scenario. Household headcount alone misses a large tub, overlapping showers and unusual schedules.

Third, have an installer identify the work outside the appliance: electrical service, gas supply, vent changes, drainage, clearances and permits. A compact heater can still require an extensive conversion. Our installation guide explains how to turn those requirements into a comparable scope.

Compare the whole project

For example, a homeowner with a functioning electric tank and a roomy utility area has a reason to request both an electric resistance replacement and a heat-pump quote. A homeowner with a tight closet must resolve physical fit and air access before relying on estimated heat-pump savings. Neither scenario produces a universal winner.

Use tankless versus tank when storage is the question, and gas versus electric when fuel is the question. Compare installed totals with water heater cost, check rebates before purchase, and use our best water heaters guide to apply the same criteria to model selection. Bring your shortlist to qualified installers for a site-specific assessment.