Quick answer: The Hayward HeatPro heat pump is our best-overall pool heater — a COP of 5–6 means roughly $1 of electricity buys $5 of heat, ideal for warm-to-temperate climates. If you need the pool warm tonight or live somewhere a heat pump stalls below 50°F, the Pentair MasterTemp 400 gas heater delivers fast, on-demand heat instead. For a smaller pool or spa, the FibroPool FH270 heat pump and SmartPool SunHeater solar panels both cost far less to run.
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 HP21405T | Heat pump | Best overall | ~$6,500-$7,000 | ★★★★★ |
| Pentair MasterTemp 400 | Gas | Fast heat, cold climates | ~$4,789 | ★★★★½ |
| FibroPool FH270 | Heat pump | Best value heat pump | ~$1,999 | ★★★★☆ |
| SmartPool S601P SunHeater | Solar | Lowest running cost | ~$180 | ★★★★☆ |
1. Hayward HeatPro HP21405T — Best Overall
Hayward HeatPro HP21405T (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. See our best gas pool heater roundup for the full natural-gas lineup by size, or our best propane pool heater guide for the LP version of this same lineup if you have no gas line.
3. FibroPool FH270 — Best Value Heat Pump
FibroPool FH270 (70,000 BTU)
- 70,000 BTU, COP 5.77 — ideal for above-ground and smaller in-ground pools up to ~15,000 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; electric resistance for spas and small pools where none of the above make sense.
- Pool size (BTUs) — Size gas at ~15–20 BTU/gallon and heat pumps at ~5–7 BTU/gallon. Bigger is faster and rarely wasteful. Run the exact numbers for your pool with our BTU calculator and sizing chart.
- 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. See our installation cost breakdown for what labor, gas-line runs, and electrical hookups actually cost by type, or our step-by-step install guide for what you can DIY versus what legally needs a licensed pro.
- Budget & financing — If paying the full installed cost upfront isn’t ideal, dealer and retailer financing (GreenSky, Affirm, store cards) is a real option — see our pool heater financing guide for real APRs and the deferred-interest fine print worth reading first.
- Weather protection — Whichever type you buy, a fitted pool heater cover keeps the cabinet’s electronics and coils from taking on rain, snow, and debris between uses.
- Maintenance — A few monthly checks and one annual tune-up keep any heater running efficiently for years; see our pool heater maintenance guide for the full schedule.
- Parts & repairs — Igniters, sensors, and thermostats typically last only 3-5 years and are cheap DIY swaps; see our pool heater parts guide for what fails first and what’s worth calling a pro for, or our thermostat guide if the display and the water temperature don’t match.
- Automation ecosystem — If you already run Jandy’s AquaLink pool automation, the Jandy JXi and JE-series lineup plugs in natively, though its dealers hide pricing more than Hayward or Pentair do.
- Commercial or shared pools — HOAs, hotels, gyms, and apartment complexes need NSF/ANSI 50-certified equipment and much higher BTU output than any residential heater on this page; see our best commercial pool heater guide for dealer-priced options up to 1.8 million BTU.
- Exact in-ground gallon count — A 10,000-gallon pool and a 25,000-gallon pool need meaningfully different BTU output even within the same heater type; see our best inground pool heater guide for picks tiered by pool size, plus the 240V/50-amp and gas-line specs a permanent hookup requires.
- Comparing brands — Warranty length, price tier, and where a brand actually sells vary more than most buyers expect; see our pool heater brands compared guide before you settle on a manufacturer.
- Timing the purchase — Prices drop in fall and winter as swim-season demand fades, then climb again in spring; see our when pool heaters go on sale guide if your purchase isn’t urgent.
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 — or see our full MasterTemp size guide if 400,000 BTU is more than your pool needs — and add a solar SunHeater to slash whatever you spend on either. If you’d rather stick with a single brand across gas, heat pump, and spa heaters, Raypak’s lineup or Jandy’s JXi/JE lineup are the other major single-brand options worth comparing, and Sta-Rite’s Max-E-Therm gas line — a Pentair-owned brand that shares MasterTemp’s engineering — is worth cross-shopping if MasterTemp is backordered locally. For exact monthly numbers by heater type, see our pool heating cost breakdown. Still torn between the two most common types? Our gas vs. heat pump decision guide walks through climate, budget, and swim-frequency tradeoffs side by side.