Energy Efficient Water Heaters
Buying Tips

Why are high-efficiency water heaters important? What is the Energy Star product? Can it really save you money?

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Energy-efficient water heaters, high-efficiency systems, and Energy Star appliances are all used when talking about heating products with low heat loss and use over 80% of their energy for heating.

They utilize new technology and are designed to save energy, resources, and money, also reduce greenhouse emissions, and provide better environmental protection than the low-efficient models.

If you are using natural gas for water heating, you can find many manufacturers and models that comply with the Energy Star requirements – just look for units with an energy factor of 0.9 and over. They are known as the Energy Star water heaters. If using electricity for heating, the only option is to buy an electric heat pump, such as this Voltex from AO Smith.

If you consider buying a new unit or replacing the old one, take advantage of this improved technology; energy-efficient or high-efficiency water heaters are a good and cost-effective replacement option for your home.

Brands and types to consider

The most energy efficient water heaters available are gas-fired with condensing technology. You can buy either tank-type or tankless.

Water heaters that are considered energy-efficient are designed to reduce the energy loss from their tanks by having a higher level of insulation around the tank, one-way valves where pipes connect to the tank (heat traps), or a special helical heat exchanger as found in Polaris. With an efficiency of 90% and higher, these models can substantially reduce the standby heat loss but are more expensive.

Condensing and "near-condensing" gas water heaters or boilers save much more energy when compared to traditional models, and their energy efficiency is over 90%.

Manufacturers of condensing heating units like Vaillant, Baxi, Junkers, Viessmann are popular in Europe, but condensing boilers are fairly new products in North America. You can find them among Noritz, Rinnai, and Takagi tankless water heaters while AO Smith and Polaris among tank-type heaters.

If gas-powered, energy-efficient water heaters interest you, consider buying a sealed combustion unit, also known as direct vented or power vented.

What does the sealed combustion mean?

The outside fresh air is brought in directly to the water heater while exhaust gases are vented outside, keeping combustion independent from the inside air. This is done through the special venting kit, which usually comes separately from the heater.

Tip: Consider insulating hot water delivery pipes to prevent heat loss and energy waste, especially in the area where pipes run through the unheated portions of your home.

Note: "ENERGY STAR was developed by the US Environmental Protection Agency (EPA) and the US Department of Energy to reduce energy use and air pollution by labeling energy-efficient, cost-saving products used in homes and offices." (source energystar.gov).

HE tank type heaters

A gas-powered energy efficient water heater from the tank type group utilizes the same technology as the standard type: water in a glass-lined steel tank is heated by the burner located at the bottom of the tank.

Here is the difference...

High-efficiency (HE) water heaters have a different quality and thicker tank insulation for better heat retention and reduced standby heat loss. Standby heat loss is a loss of heat through the walls of the tank, representing nothing more than energy waste.

Tanks are built with heat traps, where water flows into the tank but prevents the unwanted flow of hot water out of the tank, and with high-efficiency burners transfer more heat to the water.

As we said before, to increase the efficiency further, manufacturers may add a power vent to accelerate the venting of the combustion gases. Flue baffle and flue damper have improved control, reducing the heat loss through the flue vent.

They are using electronic ignition, not a pilot light that is wasting gas when there was no need for heating.

Energy Star water heaters use at least 5% less energy than standard models.

Buying tips

Energy Star water heaterEnergy Star

If you have decided to buy an energy-efficient water heater, either buying through an online store, retailers like Home Depot, Lowe's, or contractors, look for the blue tag on the unit and familiar logo ENERGY STAR (see the picture). Check also for rebates and government tax credits.

If you have a favorite brand, like Rinnai, Rheem, Noritz, Takagi, Bosch, AO Smith... find out which qualified Energy Star water heaters are available on the market. See the prices here.

Do you prefer tankless heaters or tank type?

Decide about the size/capacity you need, is your preference a 40 or 50-gallon tank type or 2-bathroom tankless heater.

If you plan to replace the old heating unit, and you were happy with the capacity, then use the same tank size. If you don't know the size, check out the manual or find the sticker on the unit.

The first-hour rating is another critical factor when selecting the best energy-efficient water heater; it shows how much hot water the unit can deliver during a busy hour. It is essential to have enough hot water during peak hours, i.e., growing children and teenagers, when adding a shower, dishwasher, or washing machine.

Another important factor is the Energy Factor, EF or Universal Energy Factor - UEF. The recommendation is to buy a heater with the highest EF (UEF) if it is in your price range.

Requirements for water heaters to qualify for Energy Star

Gas-powered storage tank-type water heater should have an energy factor (EF/UEF) of 0.67 or higher and a first-hour rating of at least 67 gallons per hour.

Gas tankless water heater requirement for EF (UEF) is 0.82 or higher and 2.5 GPM water flow or higher - 109 F temperature rise or higher.

Requirements for condensing gas storage heaters are; EF (UEF) 0.80 or higher and the first-hour rating 67 gallons per hour, minimum.

The heat pump water heater should have an EF (UEF) of 2 or higher and a first-hour rating of 50 GPH or higher.

Solar water heaters should have Net solar energy contribution equivalent to ≥ 7.0 GJ/year.

See all the requirements here.

Finally, collect several quotes from the contractors or retailers and make a wise decision about your energy-efficient water heater.

Also, keep in mind the following:

"If everyone in the US purchasing a standard gas water heater this year, choose a qualified Energy Star model instead, we would prevent one billion pounds of carbon dioxide from entering the atmosphere, the equivalent of creating 132,000 acres of forest ." (source energystar.gov).

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