Water Heaters

Buying a Water Heater

Fuel type, size and price

Even if you have no plans to replace an aging or unreliable water heater right this moment, it's good to do some research so you can get back to hot showers a lot quicker when it finally breaks down for good.


Look for a water heater that fits your family's needs and has the highest level of energy efficiency you can afford. Spend a little extra for efficiency; it'll really pay off down the road.

Fuel options

If you're currently using an electric heater and natural gas is an option, switching can save you a lot of money. Oil and propane water heaters are less expensive to operate, particularly tankless models. Other money-saving options include solar water heaters and heat pump systems.

For safer gas or oil heating, choose sealed combustion or power-venting systems. Power-vented equipment uses indoor air for combustion but vents exhaust outside using a fan. In sealed combustion, outside air is brought in for combustion and exhaust gas is vented outside, separating the entire process from indoor air. If a home is too airtight, venting through the chimney could cause dangerous exhaust to backdraft into the house.

Sizing a water heater

A water heater should have enough capacity to cover the busiest daily usage time. First hour rating (FHR) is the number of gallons of hot water that can be provided in one hour, starting with a full tank. Whether your family uses more hot water in the morning or evening, calculate the highest hourly need and choose a rating within a few gallons of it.

Using the chart below, multiply each activity by the number of people who do it in your home's busiest hour. Of course, conservation methods, like low-flow showerheads and water-efficient appliances will make your requirements a lot less. Talk to an experienced dealer or two to ensure you've estimated correctly.


Avg. Gallons




20 - 30





Dishes - Handwashed


Dishes - Machine Washed


Laundry - Washing Machine


Tankless water heaters are sized according to their gallons-per-minute (gpm) flow rate, which will be between 2 and 5. Gas-fired tankless water heaters have higher flow rates than electric, but a constantly burning pilot light on some models means gas-demand water heaters can potentially waste a lot of energy. Solar water heaters should be able to provide two-thirds to three-quarters of your needs, with a backup system covering the rest.

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