Our developed this pool heat pump calculator to help pool owners determine the appropriate size and capacity of a heat pump needed for their specific pool.
This pool heat pump size calculator takes into account various factors such as pool dimensions, desired temperature, ambient air temperature, and other environmental conditions to provide accurate recommendations.
Imagine you have a 20×40 foot rectangular pool in a region with a mild climate. You want to maintain a comfortable swimming temperature of 82°F (28°C). The calculator would consider these parameters along with factors like average wind speed and humidity to suggest the ideal heat pump size, typically measured in British Thermal Units (BTUs) per hour.
Pool Heat Pump Calculator
| Pool Size (ft) | Volume (gallons) | Desired Temp Rise (°F) | Required BTU/hr |
|---|---|---|---|
| 10 x 20 | 8,000 | 10 | 666,400 |
| 12 x 24 | 10,800 | 10 | 1,079,808 |
| 15 x 30 | 16,830 | 15 | 2,523,806 |
| 16 x 32 | 21,063 | 12 | 2,631,499 |
| 18 x 36 | 24,235 | 12 | 2,904,093 |
| 20 x 40 | 30,000 | 8 | 2,399,040 |
| 25 x 50 | 46,875 | 10 | 4,685,625 |
| 30 x 60 | 78,125 | 10 | 7,812,500 |
| 35 x 70 | 107,250 | 15 | 15,657,750 |
| 40 x 80 | 128,000 | 10 | 11,000,000 |
| 45 x 90 | 162,000 | 12 | 17,203,200 |
| 50 x 100 | 208,333 | 15 | 24,999,900 |
Pool Heat Pump Calculation Formula
BTU/hr = Pool Volume x Temperature Rise x 8.33Where:
- Pool Volume is in gallons
- Temperature Rise is the difference between desired pool temperature and average air temperature
- 8.33 is the number of BTUs needed to heat one gallon of water by 1°F
For a more precise calculation, additional factors are considered:
BTU/hr = Pool Volume x Temperature Rise x 8.33 x (1 + Factor for wind/humidity)Let’s say you have a 20,000-gallon pool, want to raise the temperature by 10°F, and live in an area with moderate wind:
BTU/hr = 20,000 x 10 x 8.33 x 1.25 (wind factor)
BTU/hr = 2,082,500This pool would require a heat pump with a capacity of approximately 2,082,500 BTU/hr.
How do I calculate what size pool heat pump I need?
To determine the appropriate size of a pool heat pump, follow these steps:
Measure your pool’s surface area in square feet
Determine the desired temperature rise
Consider your climate and pool usage patterns
Use the formula or a specialized calculator
For a 16×32 foot pool (512 sq ft) in a moderate climate, aiming for a 15°F temperature rise:
- Calculate pool volume: 512 sq ft x 5.5 (average depth) = 2,816 cubic feet = 21,063 gallons
- Apply the formula: 21,063 x 15 x 8.33 = 2,631,499 BTU
- Add 20% for environmental factors: 2,631,499 x 1.2 = 3,157,799 BTU
You would need a heat pump with a capacity of about 3,160,000 BTU/hr.
How much can a heat pump heat a pool?
Heat pumps can raise pool temperatures by 10-15°F (5.5-8.3°C) above the ambient air temperature.
If the ambient air temperature is 70°F (21°C), a properly sized heat pump could potentially heat your pool to 80-85°F (26.7-29.4°C).
For optimal performance and energy efficiency, it’s recommended to maintain a pool temperature no more than 15°F above the average air temperature in your area.
How long does a heat pump take to heat a pool?
The time required to heat a pool depends on several factors:
- Pool size
- Desired temperature increase
- Heat pump capacity
- Ambient air temperature
- Use of pool cover
For a 20,000-gallon pool, raising the temperature by 10°F with a 100,000 BTU/hr heat pump:
Time = (20,000 gal x 10°F x 8.33) / 100,000 BTU/hr
Time = 16.66 hoursHow many BTUs do I need for a 15×30 pool?
To calculate the BTUs needed for a 15×30 foot pool:
- Calculate pool volume: 15 x 30 x 5 (average depth) = 2,250 cubic feet = 16,830 gallons
- Assume a desired temperature rise of 15°F
- Apply the formula: 16,830 x 15 x 8.33 = 2,103,172 BTU
- Add 20% for environmental factors: 2,103,172 x 1.2 = 2,523,806 BTU
For a 15×30 foot pool, you would need a heat pump with a capacity of approximately 2,524,000 BTU/hr.
References
- U.S. Department of Energy – Energy Saver: Swimming Pool Heating
- ENERGY STAR: Pool Pumps
- American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE): ASHRAE Handbook – HVAC Applications
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