There’s a lot you have to consider when choosing a new water heater. For those who are energy-conscious or worried about annual operating costs, a high efficiency water heater could be perfect for you. So what do you need to know before choosing a high efficiency water heater?

How a high efficiency water heater is rated

The efficiency of water heaters is rated by each unit’s energy factor (EF). Energy factor is an indication of how much hot water is produced by a water heater per unit of fuel that’s consumed in a typical day. The higher the energy factor, the more efficient the unit is.

How fuel-source affects the efficiency of a water heater

Although energy factor is a good way of comparing the efficiency of water heaters, it can be misleading when you consider the fuel-source of the unit. For example, a typical electric water heater has an energy factor of around .9, while a typical gas water heater has an energy factor of around .6. However, it takes about three times as much energy to deliver a unit of electricity as it does to deliver a unit of gas. As a result, gas water heaters end up being much more efficient.

The best way to use energy factor when choosing a high efficiency water heater is to compare the EF of units that use the same fuel source.

Choosing a high efficiency water heater

High efficiency models are available for every type of water heater. Since a majority of water heaters in the US and San Francisco area use either natural gas or electricity as the fuel source, we’ll stick to describing those types of units.

High efficiency natural gas water heaters start with an EF of around .65, compared to standard units with an EF of around .6. When choosing one of these models, look for a unit with an Energy Star label and an EF of .67 or better.

Tankless water heaters are another natural gas option for homeowners. While these units have an EF of around .82, it’s important to note that they cost nearly twice as much as standard water heaters.

If you’re looking for an electric unit, your best option is an electric heat pump water heater. These units use the same technology as heat pumps that heat and cool your home, and have an EF of around 2.2.

If you have any questions about a high efficiency water heater, or if you’d like a water heater installed in your home, contact Cabrillo, your San Francisco plumbing, heating and cooling company. We service the San Francisco area and surrounding cities like Los Altos, Orinda, Lafayette and Redwood City.