Recovery rate and first hour recovery are generally metrics to consider when considering a new water heater. The recovery rate measures how quickly a water heater can reheat a tank of cold water after use. It’s measured by gallons per hour (GPH) and reflects the heater’s heating efficiency. A higher recovery rate means the tank can replenish hot water more rapidly, which may be beneficial when you’ve got situations involving simultaneous hot water demands.

The First Hour Rating (FHR) indicates how much hot water a water heater can deliver in the first hour after a cold start. It combines the amount of hot water stored in the tank with the heater’s heating power. Higher FHRs generally mean better performance during peak usage times.

Tankless water heaters may heat 2-5 gallons per minute, which may not be enough for high-demand use.

Explore our water heater sizing guide to learn what’s right for your home

While all energy prices fluctuate, gas water heaters may cost less to operate than electric models over a 10-to-12-year lifespan, depending on usage patterns, energy pries, maintenance and system efficiency. Current models sometimes feature improved burner designs and better tank insulation for greater efficiency.

Uniform Energy Factor

Water heater efficiency is measured by the Uniform Energy Factor (UEF), which shows how much of the energy used is converted to hot water. Although natural gas water heaters usually have a lower UEF than electric models, natural gas prices may result in lower operating costs in most cases.

Source-to-site energy dynamics

Natural gas offers a “direct-use” energy advantage. When you heat water with gas on-site, you may avoid some energy losses that occur when converting fuel to electricity at a power plant and transmitting it over long distances. This may offset some of the energy loss reflected in the UEF.

Since natural gas water heaters have higher recovery rates than electric, you may be able to install smaller tanks in tight places without sacrificing performance. A variety of compact natural gas tankless water heaters options are generally available. While venting is required for all gas water heaters, modern high-efficiency options like power venting make natural gas water heaters easier to install in a wider range of locations, subject to applicable codes and site conditions.

Many traditional gas water heaters may provide hot water during power outages. While electric models need electricity to function, gas units may continue delivering hot water when the power is out. Modern gas water heaters typically also incorporate safety innovations like Flammable Vapor Ignition Resistance (FVIR) technology and sealed combustion systems designed to reduce some fire risks caused by nearby flammable vapors.