Energy Efficient Water Heater

Why high efficiency water heaters are important? What is Energy Star?

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Energy efficient water heaters, high efficiency systems and Energy Star appliances are all the terms for new technology and new approach in saving energy, saving money for you and step up toward reducing greenhouse emission and better environment protection.

If you are using a natural gas for water heating, you can find many manufacturers and models that comply with the Energy Star requirements. They are known as the Energy Star water heaters.

Now is the time for you to take advantage of this improved technology, since energy efficient or high efficiency gas heaters are good and cost-effective replacement option for your existing heating system.

Energy efficient water heater suggestions

The most energy efficient water heater models available are generally gas-fired with the condensing technology.

These high efficiency units have higher levels of insulation around the tank and one-way valves where pipes connect to the tank, substantially reducing standby heat loss. But, they are more expensive.

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

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

If gas powered, energy efficient water heater 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 totally independent from the house air. This is done through the special venting kit, which usually comes separate from the heater.

Tip: Consider insulating hot water delivery pipes so you can prevent heat loss and energy waste, 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

HE tank type heaters

Gas powered energy efficiency water heater, tank type, utilizes the same technology as standard gas storage water heaters: water in glass-lined steel tank is heated by a burner that is located at the bottom of the tank.

Here is the difference...

High efficiency water heaters have an extra quality and thicker tank insulation for better heat retention and less standby loss. Standby loss is loss of heat through the walls of the tank, representing a pure waste of energy.

Tanks are built with the heat traps, where water flows into the tank but prevent unwanted flow of hot water out of the tank; and with high efficient burners that 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 combustion gases. Flue baffle and flue damper have improved control, reducing the heat loss through the flue vent.

Energy efficient water heater is using electronic ignition not pilot light that was wasting gas when there was no need for heating.

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

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Buying Tips

energy star logo for energy efficient water heatersIf you have decided to buy an energy efficient water heater, either buying online, through retailers like Home Depot, Sears, Lowe's, or contractors, look for the blue tag 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, Bradford White, Kenmore... find out what qualified Energy Star water heaters are available on the market.

Do you prefer tankless heaters or tank type?

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

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

First-hour rating is another important criteria when selecting the best energy efficient water heater; it shows how much hot water the unit can deliver during a busy hour. It is especially important to have enough hot water during the peak hour; i.e. when having growing children, when adding a shower, dishwasher or washing machine.

Another important factor is Energy Factor, EF. Recommendation is to buy a heater which has the highest EF, if it is in your price range.

Requirements for water heaters to qualify for Energy Star

Gas storage type energy efficient water heater should have EF (energy factor) 0.67 (used to be 0.62) or higher, and the First Hour Rating at least 67 gallons per hour.

Gas tankless water heater requirement for EF is 0.82 or higher and 2.5 gpm over 109 F temperature rise or higher.

Requirements for condensing gas storage heaters is; EF 0.80 or higher and the First Hour Rating 67 gallons per hour min.

Heat pump water heater should have EF 2 or higher and the First Hour Rating 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 a contractors or retailers and make a wise decision about your energy efficient water heater.

... and keep in mind...

If everyone in the U.S. purchasing a standard gas water heater this year chose an qualified gas storage model instead, we would prevent one billion pounds of carbon dioxide from entering the atmosphere, the equivalent of creating 132,000 acres of forest 9" (source

(All pictures are courtesy of