How Much Does a Pool Heat Pump Cost to Run

Pool owners considering a heat pump need clear, practical cost estimates to plan energy use and budgets. This article explains how pool heat pumps work, shows how to calculate running costs using the heat pump’s coefficient of performance (COP), provides typical monthly and seasonal cost estimates across U.S. climates, and offers actionable tips to reduce expenses while maintaining comfortable water temperatures.

Heat Pump Size (BTU)	Typical COP	Estimated Monthly Cost (Moderate Climate)	Estimated Daily Runtime
30,000 BTU	5.0	$25–$60	3–6 hours
50,000 BTU	5.0	$40–$100	4–8 hours
100,000 BTU	5.0	$80–$200	6–12 hours

How A Pool Heat Pump Works And Why Efficiency Matters

Pool heat pumps extract heat from outside air and transfer it to pool water using a refrigeration cycle and a heat exchanger. Because they move heat instead of creating it by combustion or resistance, they are typically much more efficient than electric resistance heaters.

The operational efficiency of a heat pump is expressed as the Coefficient Of Performance (COP), which is the ratio of heat output to electrical energy consumed. A COP of 5 means the pump delivers five units of heat for every unit of electricity used. Higher COPs lower running costs.

Key Factors That Determine Running Costs

Several variables influence how much a pool heat pump costs to run. Understanding each factor helps create accurate budget projections and targeted savings strategies.

• Heat Pump Size And Output: Measured in BTU/hour, larger pumps produce more heat but can run more efficiently when properly matched to pool size.
• Coefficient Of Performance (COP): Higher COP values reduce electricity consumption per unit of heat delivered.
• Electricity Rate: Measured in dollars per kilowatt-hour (kWh); U.S. residential rates vary widely by state and time of day.
• Desired Water Temperature And Pool Size: Larger temperature rises and larger pools require more energy to maintain.
• Ambient Air Temperature: Heat pumps are less efficient in colder air; COP typically drops as ambient temperature falls.
• Heat Loss From The Pool: Evaporation is the biggest source of heat loss; wind, uncovered surfaces, and low water temperatures increase losses.
• Runtime And Control Strategy: How long and when the pump runs (continuous vs scheduled) directly affects monthly costs.

How To Calculate Running Costs: Step-By-Step

Calculations use the heat pump output in BTU, COP, and local electricity rates. The process below provides a practical estimate of cost per hour and per month.

Step 1: Convert BTU Output To Kilowatts

One kilowatt equals 3,412 BTU/hour. So divide the heat pump’s BTU output by 3,412 to get kilowatts (kW) of heat delivered.

Step 2: Account For COP To Find Electrical Input

Electrical Input (kW) = Heat Output (kW) / COP. This gives the power draw while the unit is operating at that COP.

Step 3: Multiply By Electricity Rate And Runtime

Cost Per Hour = Electrical Input (kW) × Electricity Rate ($/kWh). Monthly Cost = Cost Per Hour × Hours Per Day × Days Per Month.

Example Calculation

Example: 50,000 BTU heat pump with COP 5 and electricity rate $0.15/kWh. Heat Output = 50,000 / 3,412 = 14.65 kW. Electrical Input = 14.65 / 5 = 2.93 kW. Cost Per Hour = 2.93 × $0.15 = $0.44. If the pump runs 6 hours/day: daily cost $2.64; monthly (30 days) about $79.20.

Typical Running Costs By Climate And Pool Size

The following estimates assume typical COPs around 4.5–6.0 depending on ambient temperature, and U.S. average electricity rates ranging from $0.12 to $0.20/kWh.

Pool Size	Typical Heat Pump	Estimated Monthly Cost (Warmer Climate)	Estimated Monthly Cost (Cooler Climate)
Small (10k–15k gallons)	30,000–50,000 BTU	$20–$60	$40–$100
Medium (15k–30k gallons)	50,000–75,000 BTU	$40–$100	$70–$180
Large (30k+ gallons)	75,000–150,000 BTU	$80–$200	$140–$400

These ranges reflect seasonal differences. In warm climates, heat pumps achieve higher COPs and need to run fewer hours to maintain temperature. In cold climates, pumps run longer and COP drops.

Comparison: Heat Pump Versus Gas And Electric Resistance Heaters

Understanding alternatives helps evaluate whether a heat pump is the best choice.

• Gas Heaters: Provide fast heat and perform well in cold air, but fuel costs and emissions can be higher. Running cost depends on natural gas or propane prices but typically exceeds a high-COP heat pump over time.
• Electric Resistance Heaters: Low upfront cost but low efficiency; 100% of electricity becomes heat, making operating costs higher than heat pumps for continuous heating.
• Heat Pumps: Higher upfront cost but lower operating cost in most climates because of COPs often between 4 and 8. They are the most energy-efficient option for sustained pool heating in moderate climates.

Practical Examples With Realistic Rates

Example 1: 50,000 BTU, COP 5, electricity $0.13/kWh, runtime 6 hours/day. Heat Output kW 14.65; electrical input 2.93 kW; hourly cost $0.38; monthly (30 days) $68.40.

Example 2: 100,000 BTU, COP 4.5, electricity $0.18/kWh, runtime 8 hours/day. Heat Output kW 29.3; electrical input 6.51 kW; hourly cost $1.17; monthly (30 days) $280.80.

These examples show how COP and electricity rate are the main cost drivers. Slight changes in COP or kWh price produce noticeable differences in monthly bills.

Tips To Reduce Pool Heat Pump Running Costs

Small changes in pool management and equipment can significantly lower heat pump energy use and cost.

• Use A Quality Solar Or Thermal Cover: Covers cut evaporation and heat loss, reducing runtime. This often provides the best ROI for reducing costs.
• Improve Insulation And Windbreaks: Reducing wind exposure and insulating plumbing minimizes heat loss.
• Set Realistic Temperature Targets: Lowering setpoint by just 2–4°F can cut energy use meaningfully.
• Run The Pump During Warmer Periods: Heat pumps deliver more heat per kWh on warmer days; scheduling runtime for daytime can improve efficiency.
• Use Variable-Speed Pool Pumps: Matching circulation to heat pump needs and running at lower speeds reduces overall system consumption.
• Maintain The Unit: Regular cleaning of coils and ensuring proper refrigerant charge maintains rated COP.

Selecting The Right Size And Model For Cost Efficiency

Proper sizing avoids oversizing or undersizing, both of which can increase costs. A correctly sized heat pump runs efficiently without excessive cycling.

Consult local dealers and use these guidelines: 30,000–50,000 BTU for small pools, 50,000–75,000 BTU for medium pools, and 75,000+ BTU for large pools. Account for climate, desired season length, and pool insulation when choosing capacity.

Incentives, Rebates, And Long-Term Savings

Many utility companies and state programs offer rebates or incentives for high-efficiency pool heat pumps or for switching from gas to electric heat pumps. Federal or state tax credits occasionally apply to energy-efficient equipment; check current local programs for availability.

While upfront cost is higher than simpler heaters, the payback period is often 2–6 years depending on energy prices, usage patterns, and incentives.

Maintenance Practices That Preserve Efficiency

Regular maintenance keeps the heat pump operating near its rated COP and avoids costly breakdowns.

• Clean evaporator coils and check for debris monthly during the season.
• Inspect and replace filters on the pool circulation system to ensure proper flow.
• Schedule professional service for refrigerant checks and electrical inspections annually.
• Monitor runtime and energy use periodically to detect efficiency declines early.

When To Consider Alternative Or Hybrid Systems

In very cold climates or for pools requiring rapid temperature increases, a hybrid system combining a heat pump with a gas booster offers flexibility. The heat pump handles normal heating economically, while gas provides quick boosts in cold spells.

Solar thermal systems can work well as a supplement, further reducing heat pump runtime and operating costs.

Common Questions About Running Costs

How Much Electricity Does A Heat Pump Use Per Hour?

Electricity use depends on heat output and COP. A 50,000 BTU unit at COP 5 uses about 2.9 kW per hour; a 100,000 BTU unit at COP 4 uses about 7.2 kW per hour. Multiply by kWh price to get cost per hour.

Will Running The Heat Pump All Night Be Cheaper?

Running during warmer daytime hours typically yields better COP and lower cost per unit of heat. Nighttime running in cold air reduces COP and increases cost unless time-of-use electricity rates make overnight power cheaper.

How Much Can A Solar Cover Save?

A well-fitted solar cover can reduce heat loss by up to 70–90% relative to an uncovered pool, often translating into halved heating runtime and substantial monthly savings.

Checklist For Estimating Your Pool Heat Pump Costs

• Pool volume (gallons)
• Desired temperature rise and seasonal usage days
• Heat pump BTU rating and manufacturer COP at local ambient temps
• Local electricity rate ($/kWh) and any time-of-use pricing
• Estimated daily runtime (hours)
• Cover and insulation strategies

Step	Action
1	Convert pump BTU to kW: BTU / 3,412
2	Divide by COP to get electrical input (kW)
3	Multiply by $/kWh to get $/hour
4	Multiply by hours per day and days per month

Applying this checklist with local inputs provides a reliable estimate of monthly costs and supports decisions on sizing, operational strategy, and investments in energy-saving measures.

U.S. Department Of Energy and utility providers are good starting points for checking local energy rates and available rebates. Working with a reputable local installer ensures correct sizing and efficient installation to minimize long-term running costs.