Water Heating Types

Your home’s largest energy consumer is your electric water heater. Use our guide to learn about the most common types of water heaters used in Hawaii and decide on the best option for your home.

You can download the PDF here.

Did you know?

Switching to more energy-efficient options can save you up to 40% on your electric bill! Pay less with Hawaii Energy rebates.

Conventional Storage Water Heaters

  • How they work: Electric power constantly heats water in a tank. Hot water is released from the top of the tank while cold water is replaced at the bottom.
  • Pros: Tank is always full and hot water is readily accessible.
  • Cons: Constantly requires energy to keep a reservoir of hot water at the ready. This is called standby heat loss and it can waste over $750 per year for a household of four people.

Tankless or Demand-Type Water Heaters

  • Also known as demand-type or instantaneous water heaters.
  • How they work: Electric power heats water directly and only when needed. Cold water is heated as it travels through the unit, eliminating the need for a tank.
  • Pros: Can be as much as 50% more efficient than traditional storage water heaters. Standby heat loss avoided as there is no tank.
  • Cons: Water flow rates vary, so more than one unit may be required to supply enough hot water simultaneously for multiple people in your household. Find out more here.

Heat Pump (Hybrid) Water Heaters

  • How they work: Like a refrigerator in reverse – it pulls in heat from the air outside to warm water inside.
  • Pros: 2x as efficient as a conventional water heater, cutting water heating cost in half. Hawaii Energy rebates makes this upgrade more affordable.
  • Cons: Powered by fossil fuel electricity.

Could a heat pump water heater be best for your home? Check out our Heat Pump Water heater guide.

Solar Water Heaters

  • How they work: Clean and free energy is generated by the sun. Built-in parts called “collectors” convert energy to heat water, which is then stored in a tank.
  • Pros: Lowest energy usage of all types, and with proper maintenance, will provide savings for decades to come. Single or dual tank options available.
  • Cons: High up-front cost. (However, Hawaii Energy rebates and state/federal tax credits can help.) Figure out your costs here.