Pool maintenance
Pool heater guide: gas, electric, heat pumps, and solar
Gas heats fast at $5 to $12 a day to run, heat pumps cost less to run but need 60 plus degree air, electric resistance is rare and expensive, solar is free to run but slow and needs roof space. Pick by how often you want to swim and your climate.
2 min read · Updated
How to choose
| Heater type | Upfront | Run cost | Heats fast? | Best for |
|---|---|---|---|---|
| Natural gas | $2,000 to $4,000 | $5 to $12 per day | Yes (1 deg/hr) | Northern, occasional use |
| Propane | $2,000 to $4,000 | $10 to $25 per day | Yes | Off-grid, weekend use |
| Heat pump | $3,000 to $5,500 | $2 to $6 per day | Slow (0.5 deg/hr) | Southern, daily use |
| Solar (panels) | $3,000 to $7,000 | $0 | Slow, weather-dependent | Sunny climates, season extension |
| Electric resistance | $1,000 to $2,500 | $15 to $40 per day | Slow | Spas only, rarely pools |
Gas (natural or propane)
Heats fast. Natural gas runs $5 to $12 a day for a typical pool. Propane is double that. Pick gas if you want to fire it up Friday and swim Saturday.
Sizing rule: 1 BTU heats 1 lb of water 1 degree. A 400,000 BTU heater raises a 20,000 gallon pool about 1 degree per hour.
Lifespan 8 to 12 years. Watch for corrosion in salt pools (use a salt-rated heater).
Heat pump
Pulls heat from outside air and dumps it into the pool. Cheap to run, slow to heat. Needs 60 degree air to work well, so it is a southern and shoulder-season tool, not a December rescue.
Best for owners who want to keep the pool at a steady temp all season and are willing to pre-heat.
Solar
Free fuel, no emissions, no monthly bill. Needs roof or ground space (about half your pool's surface area in panels). Heats slowly, gives back what the sun gives. Often paired with a gas heater as backup.
A solar cover (the bubble blanket) is the cheapest way to add heat for $100 to $300. Cuts evaporation by 70 percent and adds 5 to 15 degrees in sun.
Electric resistance
Rare for pools because power cost is brutal. Fine for a small spa. Skip for a full pool.
What size do I need
Take your pool surface area in square feet, multiply by 1,500 for moderate climate or 2,000 for cold climate. That is your target BTU.
Example: 16x32 pool = 512 sqft. 512 x 1,500 = 768,000 BTU. Round up to a 750k or 850k BTU heater.
When to call a pro
Always for installation. Gas line work, venting, and electrical bonding need a licensed installer. Most jurisdictions require a permit. Doing it yourself voids the warranty and can void your home insurance.
Frequently asked questions
- What is the cheapest pool heater to run?
- Solar panels (free), then heat pumps ($2 to $6 a day), then natural gas ($5 to $12), then propane ($10 to $25), then electric resistance ($15 to $40).
- How fast does a pool heater heat the water?
- Gas: about 1 degree per hour for a 400k BTU heater on a 20,000 gallon pool. Heat pump: about 0.5 degree per hour. Solar: a few degrees on a sunny day, nothing at night.
- Should I use a solar cover with my heater?
- Yes. A solar cover cuts evaporation by 70 percent and traps heat overnight. It pays back in one season for any heated pool, often in a single month.
- Will a heat pump work in winter?
- Below 60 degrees outside it loses efficiency fast. Below 50 most heat pumps shut off. Pair with a gas heater for cold months or accept a closed pool in winter.
- How long does a pool heater last?
- Gas heater: 8 to 12 years. Heat pump: 10 to 20 years. Solar panels: 15 to 25 years. Salt pool? Cut gas heater life in half unless it is salt-rated.
- Can I install a pool heater myself?
- Bad idea. Gas, electrical, and venting are all licensed work in most states. A pro install runs $500 to $1,500 and protects your warranty plus your homeowners insurance.
- What temperature should I set my pool to?
- 78 to 82 degrees for swimming, 86 to 88 for therapeutic and elderly users, 92 to 104 for spas. Every degree above 80 adds roughly 10 percent to your monthly heating cost.
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Written by the PRNM team
Pool Rental Near Me operates the largest peer-to-peer pool rental marketplace in the US, with 2,200+ host pools across 40+ states. Our editorial team works with hosts and licensed pool pros to keep these guides current.