Heat Pump Water Heater vs. Gas: Which Is Best?
A large part of the value HVAC technicians and professional plumbers provide is helping homeowners make smart choices about the types of appliances that best serve their needs. If your customer needs to replace their gas water heater, now could be the perfect time to help them save on monthly energy bills by switching to an ENERGY STAR® certified heat pump water heater.
Learn the details, including pros and cons, to help them choose between a heat pump water heater vs. gas.
What is a heat pump water heater?
A gas water heater generates heat to warm the water, whether it’s in the storage tank or in the pipe for tankless options. That combustion also requires space for venting exhaust.
In contrast, a heat pump water heater, also called hybrid electric, doesn’t directly generate heat but instead moves heat, without using combustion.
How does a heat pump water heater work?
Most HVAC trade pros are already familiar with heat pump technology, if by different names. Just as an air conditioner or refrigerator uses exchangers and other components to collect heat energy and remove it, a heat pump reverse-cycles that process to gather ambient heat, raise temperature higher with refrigerant and then move it to a different location.
Here’s a quick overview of how a heat pump water heater works:
A fan pushes surrounding air into evaporator coils with refrigerant.
The warm refrigerant enters the compressor, where it’s heated further.
The refrigerant travels to condenser coils, where its heat is expelled to warm the water.
The cycle starts again as refrigerant returns to the evaporator.
Because they’re also hybrid, the HPWH can switch to heating water using electricity when there’s high demand for hot water.
Comparing efficiency: heat pump vs. gas water heaters
Because an HPWH uses a different method to heat water than a gas version does, efficiency varies as well. Moving heat, as an HPWH does, typically requires less energy than generating heat.
To measure efficiency in water heaters, the U.S. Department of Energy (DOE) developed the uniform energy factor, or UEF. Water heaters fall into four separate categories—Very Small, Low, Medium and High—based on capacity, or first-hour rating (FHR).
The more efficient a water heater is, the higher the UEF. But when comparing the UEF, make sure it’s between water heaters in the same capacity category, or bin. The UEF will be listed in the specifications document for each product.
To find the best solution for your customer, compare the energy efficiency of heat pump vs. gas water heaters.
Heat pump water heater efficiency
ENERGY STAR criteria offer a breakdown of the UEF for different types of water heaters. To earn the ENERGY STAR certification for an HPWH, for example, first the FHR must be at least 45 gallons per hour.
Then, an integrated HPWH with a 240-volt line needs a minimum UEF of 3.30. An integrated HPWH that is designed for 120 volts or a split system HPWH needs a UEF of at least 2.20.
Different operating modes allow the homeowner to keep their HPWH on the most efficient setting or switch to using electricity when necessary. Your customer could also choose to set the HPWH to use only electricity, which would eliminate the efficiency gained with the heat pump.
In addition, some HPWH models have timers and settings for vacation, allowing the homeowner to save energy when they’re not home.
Gas water heater efficiency
To earn ENERGY STAR certification, gas-fired storage water heaters must have an FHR of at least 51 gallons per hour.
In addition, for tanks with volume capacity between 20 and 55 gallons, the UEF for medium draw pattern must be at least 0.81, and the UEF for high draw pattern must be at least 0.86.
For tanks with volume capacity greater than 55 gallons, the UEF must be at least 0.86.
Tankless gas water heaters must have a max gallons per minute of at least 2.8 over a 67°F rise to be eligible for ENERGY STAR certification, and UEF must be at least 0.95.
Which is more energy efficient?
With available ENERGY STAR certified HPWHs earning 2.20 UEF minimum, and gas water heaters earning 0.95 UEF at maximum, a heat pump water heater is more energy efficient than gas, whether with a tank or tankless.
How much your customers can expect to save annually will vary based on their hot water needs and the cost of different fuel sources in their area.
Heat pump water heaters pros and cons
Energy efficiency may not be your customers’ greatest concern, and factors like upfront costs, electrical availability at the home and installation costs can affect their decision. Explore the pros and cons of an HPWH.
Advantages of an HPWH:
They typically last longer: between 13-15 years compared to traditional versions with a lifespan of 10-12 years.
They save energy, which often lowers energy bills for homeowners.
While they do make some noise, they are quieter than traditional water heaters.
The hybrid nature allows them to provide hot water during high demand.
Homeowners can set options to increase or decrease efficiency and potentially implement timers.
They are suitable for many types of climates.
Drawbacks of an HPWH:
They can cost a bit more upfront; however, federal tax credits, state rebate programs and local incentives can help reduce the expense.
The installation site should have an electrical supply of 240 volts for maximum efficiency. Versions for the standard 120 volts are available, but they are less efficient.
Installing an HPWH can cost more than installing traditional gas water heaters due to several considerations: capping gas lines, routing condensation, providing appropriate air space and venting, positioning for air flow, and complying with local codes that may require mixing valves or electricity permits.
When switching from gas-fired, the homeowner will likely need a larger capacity HPWH.
They should be installed in places in the home where temperatures won’t drop below 40°F or rise above 90°F.
Benefits of heat pump water heaters
Breaking down the pros and cons above makes it clear that the benefits of an HPWH include energy efficiency, eliminating gas combustion, longer lifespan and ability to reliably deliver hot water to large households, as well as potentially much lower operating costs.
Are heat pump water heaters worth it?
Whether an HPWH is the best choice to recommend for your customer will come down to their priorities and their home’s installation capabilities.
If their home can accommodate an HPWH and they value long-term savings and energy efficiency over upfront costs, a heat pump water heater is worth it. If they’re not ready for a larger outlay right now that will pay off later, an ENERGY STAR certified gas water heater could be best for them.
Ferguson has the right water heater for your customers
No matter what your customers ultimately decide, Ferguson has a wide variety of water heaters in stock so you can meet their needs. Explore our range of ENERGY STAR compliant heat pump water heaters today.