Energy Ratings on Rheem Water Heaters

Energy Ratings

• Rheem brands, like most water heaters, are labeled with the BTU, EF and GPM and GPH ratings for energy efficiency. An EF (Energy Factor) rating describes the ratio of usable energy that a gas water heater produces. For example, an EF of 0.67 means 67 percent of the gas consumed by the heater heats water and is the minimum rating to qualify for the federal Energy Star program for water heaters. The second energy-related number used by Rheem is the GPM and GPH rating. This describes how much hot water the unit can produce in a minute (GPM) when it starts with a full tank or within an hour (GPH). Tankless water heaters are rated on a GPM basis, and conventional gas and electric storage heaters are rated on a GPH basis. The BTU capacity describes the how much power and energy the unit can harness to heat water, somewhat similar to the horsepower of an automobile. The higher the BTU capacity, the more efficient the water heater will be at producing hot water.

Conventional Gas Storage Water Heaters

• Rheem conventional gas storage water heaters have 0.49 to 0.7 EF ratings and range in residential capacities from 29 gallons to 100 gallons. Models with ratings of 0.67 and higher are Energy Star-qualified. Rheem measures gas storage water heaters on a GPH (gallons per hour) versus a GPM (gallons per minute) basis and uses a 90 degree Fahrenheit temperature rise to measure gas water heaters. Gas storage water heaters under the Rheem label have hot water recovery ranges from 36 to 40 GPH.

Tankless Water Heaters

• Rheem is a leading manufacturer of both indoor and outdoor water heaters. Gas-fueled tankless water heaters have a 0.82 EF rating. Rheem GPM ratings are based on the air temperature surrounding the unit. Rheem gas and propane tankless water heaters have a 3.9 GPM when the outdoor or indoor temperature is 77 degrees Fahrenheit, a GPM range from 8.4 to 9.5 when the temperature is 35 degrees Fahrenheit, and range from 6.7 to 7.4 when the temperature is 45 degrees Fahrenheit. Rheem electric tankless models have a 1.5 GPM for small units fit for a bathroom sink to 5.0 for a whole home unit. Tankless water heaters do not store water. They heat water “on demand,” or when it is needed. This makes them energy efficient because they use energy gas or electric energy only when you turn on the hot water faucet.

Condensing Water Heaters

• The Rheem Prestige Series condensing tankless gas water heaters have a 0.94 Energy Factor, which is about 17 percent higher than the Energy Star requirement of a 0.8 EF rating. Rheem condensing tankless water heaters recapture condensation and convert it back to useful energy, which makes Rheem models (and all condensing water heaters) among the most efficient of all water heater types and earns them the highest EF factor.