Is a Heat Pump Water Heater Right for Your Home?
Water heating is one of the largest energy users in most homes—often second only to space heating. If your electric or propane water heater is nearing the end of its life, a heat pump water heater (HPWH) may be an efficient replacement worth considering. Like any technology, heat pump water heaters come with both advantages and tradeoffs. Here’s what MEC members should know before making the switch.
How Heat Pump Water Heaters Work
Unlike standard electric water heaters that make heat using electric resistance elements, a heat pump water heater moves heat from the surrounding air into the water—similar to how a refrigerator works, but in reverse. Because moving heat takes much less energy than creating it, HPWHs can be significantly more efficient.
The Pros
Lower Operating Costs
Heat pump water heaters can use significantly less electricity than standard electric resistance units. Many households see noticeable reductions in monthly energy use for water heating, especially when replacing older electric or propane models.
Available MEC Rebates
To help offset the higher upfront cost, Missoula Electric Cooperative offers rebates for qualifying heat pump water heater installations. These incentives can make HPWHs far more affordable and shorten the payback period. Members are encouraged to check MEC’s website or contact the office for current rebate details and
eligibility requirements.
Reduced Peak Electrical Demand
A standard electric resistance water heater typically uses 4,000–5,000 watts when heating water. That high wattage contributes to peak demand on the electric system even though it may run for short periods. In contrast, a heat pump water heater usually operates at a few hundred watts while heating in heat pump mode. While some models include backup resistance elements, they run far less often.
This lower operating wattage can help reduce strain on the Cooperative’s electric system during peak periods, which benefits all members over time.
The Cons(iderations)
Space and Air Volume Requirements
Heat pump water heaters need access to enough surrounding air to operate efficiently. Most manufacturers recommend at least 700–1,000 cubic feet of air space, such as a basement, utility room, or garage. In smaller or enclosed spaces, performance may drop—or additional ducting may be required.
Cooler Surrounding Air
Because HPWHs pull heat from the air, the room they’re installed in can feel slightly cooler. In many Montana homes, this is manageable or even beneficial in summer, but it’s something to factor into your decision.
Higher Upfront Cost
Heat pump water heaters typically cost more upfront than standard electric models. However, energy savings and MEC rebates often help balance that cost over time.
HPWHs Make Sound When Operating
When the heat pump is running, a heat pump water heater produces an amount of sound similar to a dishwasher. This is something to take into consideration when installing it in a living area.
Why Going One Size Bigger Can Make Sense
When switching to a heat pump water heater, MEC recommends going up one tank size from your existing unit whenever possible.
A larger tank:
• Stores more hot water, reducing the need for backup resistance heating
• Allows the heat pump to operate more efficiently over longer, steady cycles
• Improves comfort during high use periods (showers, laundry, dishes)
For example, replacing a 50-gallon tank with a 65- or 80-gallon heat pump model can maximize efficiency without increasing energy use.
Is a Heat Pump Water Heater Right for You?
A heat pump water heater can be an excellent option if you:
• Have adequate space and air volume
• Want to reduce long-term energy costs
• Are replacing an electric or propane water heater
• Plan to take advantage of MEC rebates
If you’re unsure, a licensed electrician or plumber can help evaluate your home’s suitability. For rebate details and energy efficiency guidance, contact Missoula Electric Cooperative or visit our website. Making smart energy choices today helps keep costs down—for you and your cooperative.
