Heating a pool is the single biggest running cost most pool owners face, so picking the right heater matters more than picking the cheapest one. We compared gas, heat pump, and solar options across in-ground and above-ground pools, weighing heat output (BTUs), efficiency, climate suitability, and real-world price to land on picks that actually make sense for your setup.
Our top pool heater picks at a glance
| Heater | Type | Best for | Price | Rating |
|---|---|---|---|---|
| Hayward HeatPro HP21404T | Heat pump | Best overall | ~$3,299 | ★★★★★ |
| Pentair MasterTemp 400 | Gas | Fast heat, cold climates | ~$2,999 | ★★★★½ |
| FibroPool FH270 | Heat pump | Best value heat pump | ~$1,999 | ★★★★☆ |
| SmartPool S601P SunHeater | Solar | Lowest running cost | ~$180 | ★★★★☆ |
1. Hayward HeatPro HP21404T — Best Overall
Hayward HeatPro HP21404T (140,000 BTU)
- 140,000 BTU with a titanium heat exchanger that shrugs off salt and chemistry swings.
- High COP (~5–6) means very low running cost versus gas.
- Quiet, ultra-efficient scroll compressor and an acoustic-dampened cabinet.
- Needs air temps above ~50°F to work well — not a winter heater.
The HeatPro is our top pick for a simple reason: for most owners in warm-to-temperate climates, a heat pump is dramatically cheaper to run than gas, and Hayward’s titanium exchanger is the most durable in the class. Sized at 140,000 BTU it comfortably holds a 20,000-gallon in-ground pool in the 82–86°F range through the swim season. It heats slowly — expect 24–48 hours to warm a cold pool — so pair it with a solar cover to keep the heat you buy. Getting it delivered fast helps you start the season sooner: try Amazon Prime free for 30 days for two-day shipping on your pick.
2. Pentair MasterTemp 400 — Best for Fast Heat & Cold Climates
Pentair MasterTemp 400 (400,000 BTU)
- 400,000 BTU heats any pool fast, in any weather, day or night.
- 84% thermal efficiency and a compact, quiet cabinet.
- Best choice for spas, short swim windows, and northern climates.
- Highest per-hour running cost — you're burning natural gas or propane.
If you want the pool warm tonight — or you live somewhere a heat pump would stall — gas wins. The MasterTemp 400 is our pick over the comparable Hayward Universal H-Series for its quieter operation and faster cold-start. It’s the right tool for spas and for anyone who heats occasionally rather than all season.
3. FibroPool FH270 — Best Value Heat Pump
FibroPool FH270 (95,000 BTU)
- 95,000 BTU — ideal for above-ground and smaller in-ground pools up to ~10,000 gallons.
- Roughly half the price of premium heat pumps with the same efficiency principle.
- Simple digital controls and an easy DIY-friendly install.
For a smaller pool, the FibroPool FH270 gives you heat-pump economics without the premium-brand price. It’s not as robust as the Hayward in harsh conditions, but for a seasonal above-ground or compact in-ground pool it’s the best dollar-per-BTU deal we found.
4. SmartPool S601P SunHeater — Lowest Running Cost
SmartPool S601P SunHeater
- Uses free sunlight — essentially $0 to operate once installed.
- Modular panels connect to your existing pump; add more for more heat.
- Adds roughly 6–10°F over the season in sunny climates.
- Only works when the sun is out and needs roof or ground space.
Solar is the cheapest heat you’ll ever buy. The SmartPool SunHeater won’t deliver bathwater in April, but in summer it extends your season for free and pairs beautifully with a heat pump as a booster. Plan on 50–100% of your pool’s surface area in panels for a meaningful gain.
How to choose a pool heater
Four factors decide which type is right for you:
- Climate & timing — Gas for cold weather and on-demand heat; heat pump for warm-to-temperate all-season use; solar for free summer extension.
- Pool size (BTUs) — Size gas at ~3 BTU/gallon and heat pumps at ~5 BTU/gallon. Bigger is faster and rarely wasteful.
- Running cost — Heat pumps cost the least per month, gas the most, solar almost nothing after install.
- Install — Gas needs a fuel line and clearance; heat pumps need power and airflow; solar needs sun and space.
The bottom line
For most pools in a normal swim climate, the Hayward HeatPro heat pump is the smart long-term buy — low running cost, titanium durability, and enough BTUs for a typical in-ground pool. Choose the Pentair MasterTemp 400 if you need fast heat or live somewhere cold, and add a solar SunHeater to slash whatever you spend on either.