Does this include heat loss?

No. It’s the required output to achieve the temp rise in the given time. Losses will increase actual needs.

How does ambient affect this?

Cool/windy conditions increase losses and reduce heat pump output. Add margin or use a cover.

Can I use this for gas heaters?

It outputs BTU/hr and tons; gas heater sizing can also use BTU/hr results as a reference.

Do I need to account for COP?

This outputs required BTU/hr. Use manufacturer COP data to see electrical input needed.

Yes, 1 ton = 12,000 BTU/hr in HVAC convention.

construction calculator

Pool Heat Pump Sizing Calculator

Estimate pool heat pump size (BTU/hr and tons) to reach a target temperature rise within a chosen time window.

Results

BTUs needed: 1,251,000
Required BTU/hr: 52,125
Required tons: 4.34

How to use this calculator

Enter pool gallons and desired temperature rise.
Enter the number of hours you want to reach that rise.
Review BTUs, BTU/hr, and tonnage for the heat pump.

Inputs explained

Hours: How quickly you want to achieve the temperature increase.

How it works

BTUs needed = Gallons × 8.34 × ΔT. Required BTU/hr = BTUs ÷ Hours. Tons = BTU/hr ÷ 12,000.

Formula

BTUs = Gallons × 8.34 × ΔT
Required BTU/hr = BTUs ÷ Hours
Tons = Required BTU/hr ÷ 12,000

When to use it

Checking if a quoted heat pump size is sufficient for your pool and heating window.
Comparing size requirements for faster vs slower heating goals.
Budgeting electrical capacity needs for a heat pump.

Tips & cautions

Covering the pool reduces heat loss during heating; this calc is idealized for the initial rise.
For maintenance heat, required BTU/hr will be lower; this is for the initial temp lift.
Ambient temperature affects real performance; size with some margin if heating in cool weather.
Does not model ongoing heat loss or COP variations with ambient temperature.
Ignores wind/evaporation; consider a cover for more efficient heating.
Assumes a single continuous heating period; actual cycling may vary.

Worked examples

15k gal, +10°F in 24h

BTUs ≈ 1,251,000
BTU/hr ≈ 1,251,000 ÷ 24 ≈ 52,125
Tons ≈ 4.34

20k gal, +10°F in 12h

BTUs ≈ 1,668,000
BTU/hr ≈ 139,000
Tons ≈ 11.6

Deep dive

Estimate pool heat pump size by entering gallons, desired °F rise, and hours to heat to get required BTU/hr and tons.

Use it to sanity check heat pump sizing before purchase or installation.

FAQs

Does this include heat loss?: No. It’s the required output to achieve the temp rise in the given time. Losses will increase actual needs.
How does ambient affect this?: Cool/windy conditions increase losses and reduce heat pump output. Add margin or use a cover.
Can I use this for gas heaters?: It outputs BTU/hr and tons; gas heater sizing can also use BTU/hr results as a reference.
Do I need to account for COP?: This outputs required BTU/hr. Use manufacturer COP data to see electrical input needed.
Is tons = HVAC tons?: Yes, 1 ton = 12,000 BTU/hr in HVAC convention.

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Sizing estimate only. Heat loss, ambient conditions, and COP curves affect real performance. Confirm with manufacturer data and a pool/HVAC professional.