An inground pool heater is a permanently installed unit plumbed into your pool’s circulation loop that raises water temperature using natural gas, propane, electricity through a heat pump, or solar thermal energy. There are three real types: gas heats fastest and costs the most to run, a heat pump costs a fraction of that per swim but heats slowly, and solar is nearly free to run but only works in summer. The best pool heaters for inground pools below cover all three categories, sized to real inground pools rather than spa-scale units that show up in most listings.
Our team spent weeks comparing spec sheets, owner reviews and installation realities across ten heaters, and we kept one filter most roundups drop: every unit here is rated for inground use. That matters because plenty of cheap solar and electric listings online are sized for 5,000-gallon above-ground pools and simply cannot heat a real inground basin.
We also flagged where each heater is weak, not just where it shines. The most common owner complaints in this category are heat exchanger corrosion after four or five years, ignition or board failures, and units that were boxed into a tight equipment pad so no technician can reach the burner tray. Those show up in our notes below because they decide whether a heater is a good buy years after the purchase.
If you are still assembling the rest of your setup, our guides to cartridge filters for inground pools and pool vacuum heads for concrete pools cover the parts most owners pair with a heater.
Top 3 Picks: Pool Heaters for Inground Pools (October 2026)
Our picks split by category. The Hayward H-Series wins on raw heat output and the service network behind it, the Varpoolfaye 65,000 BTU inverter heat pump wins on running cost and quietness, and the Varpoolfaye 140,000 BTU unit covers the largest pools in the roundup with the second-quietest rating on this list.
Hayward H-Series 400K BTU
- 400000 BTU natural gas
- Digital LED panel with self-diagnostics
- Low-NOx certified
- Suits pools and spas up to 1200 sq ft
Varpoolfaye 65K BTU Inverter
- 65000 BTU inverter heat pump
- COP 6.6 efficiency
- 45 dB(A) quiet operation
- Handles pools up to 21000 gallons
Varpoolfaye 140K BTU Inverter
- 140000 BTU inverter heat pump
- COP 12.8 efficiency
- 47 dB(A) quiet operation
- Handles pools up to 42000 gallons
Best Pool Heaters for Inground Pools in October
All ten heaters below heat inground pools. Four burn gas, six run as heat pumps on 220V or 240V electricity, and the capacities run from 55,000 BTU for a small in-ground pool to 406,000 BTU for a large one.
| Product | Specifications | Action |
|---|---|---|
| Hayward H-Series 400000 BTU Natural Gas |
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 Raypak 266000 BTU Natural Gas |
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| Varpoolfaye 65000 BTU Inverter Heat Pump |
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 Hayward HeatPro 140000 BTU Heat Pump |
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| Raypak 406000 BTU Propane |
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 NATURAQUELL 55000 BTU Full Inverter Heat Pump |
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 Raypak 406000 BTU Natural Gas Cupro Nickel |
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 MICOE 100000 BTU Inverter Heat Pump |
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 FibroPool FH255 55000 BTU Heat Pump |
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| Varpoolfaye 140000 BTU Inverter Heat Pump |
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1. Hayward H-Series 400000 BTU Natural Gas Heater – Best Overall
Hayward H-Series Natural Gas Pool Heater for Inground Pools 400,000 BTU
400000 BTU natural gas
Digital LED panel with self-diagnostics
Low-NOx certified
207 pounds
Pros
- Top-tier output for a large inground pool
- Digital self-diagnostics catch faults early
- Gas and electric connections routable from either side
- Low-NOx certification for sensitive areas
Cons
- 21 percent of reviews are 1-star
- 207 pounds needs two people to move
- Combustion parts need periodic service
This is the heater most pool contractors already carry parts for, and that matters more than any spec line. Hayward built a dealer network around this line, and when a burner or a board fails you can usually find a replacement locally instead of shipping one in.
The 400,000 BTU figure is genuinely useful output rather than a marketing number. Hayward rates this model for in-ground pools and spas up to 1,200 square feet, which covers most 16×32 and 20×40 inground builds with room to spare for a spa spillover.
The digital LED control panel with self-diagnostics is the part owners mention most. It monitors heater performance and flags problems before they turn into a no-heat morning, and the same family comes in 200,000 and 250,000 BTU versions if your pool is smaller.
Connections for gas and electrical can be made on either side, which is the fix for the tight-pad problem that trips people up, and the built-in 3/4 inch gas connection removes one more fitting from the install.
Owner reviews are polarized in a way worth reading closely. Sixty-six percent are 5-star, praising heating power and straightforward controls, but 21 percent sit at 1 star with warranty friction and long-term reliability complaints. Owners on pool forums also describe cupro-nickel exchangers on earlier gas units rusted through after four or five years, with flakes blocking the flame tubes and causing intermittent ignition failure.
What you need to check before ordering
Confirm a gas line runs within reach of the pad, because a new natural gas line and meter upgrade can cost more than the heater itself. Ask the installer to leave clearance at the burner tray end so the unit can be serviced without pulling plumbing.
On a saltwater pool, verify the chemistry the installer will hold. Constant pH balance decides exchanger life more than brand name does.
Where it falls short
Gas operating cost is the real trade-off. One owner with an existing Raypak unit put it plainly in a forum thread: the heater works great, but the cost to heat the pool is the problem.
At 207 pounds it is not a weekend DIY job, and low ambient temperatures mean you will be running it more often than a heat pump in the shoulder season.
2. Raypak 266000 BTU Natural Gas Heater – Best Replacement Fit
Raypak 266,000 BTU Digital Electronic Ignition Natural Gas Pool Heater
266000 BTU natural gas
Intermittent spark ignition pilot
210 pounds
Requires 3/4 inch gas line
Pros
- Drop-in fit for older Raypak hookups
- Heats roughly 3 degrees per hour
- Cabinet does not hold residual heat
- Long-availability of serviceable parts
Cons
- Sensor and main board failures around 18 months
- Warranty service is often criticized
- Tight inlet and outlet spacing costs pressure
Raypak has built pool heaters for a long time, and this 266,000 BTU natural gas unit is the version most owners end up with when they replace a 10 to 17 year old heater of the same family. Owners report reusing the existing gas, electrical and plumbing connections without changes.
Heat delivery is the strong point. One 32×16 inground owner measured roughly 3 degrees of rise per hour, which is the kind of number that lets you warm a pool for a weekend gathering without planning days ahead.
The intermittent spark pilot only ignites on a call for heat, and the cabinet material does not retain residual heat after shutdown. That means you can set the unit next to vinyl or composite without building a metal heat sink plinth around it.
Raypak also fits a serviceability preference that matters to DIY owners.
What you need to check before ordering
Raypak requires certified professional installation or the warranty is void, so plan for a licensed gas fitter. Confirm your existing gas line is 3/4 inch and sized for the load.
Check inlet and outlet spacing. Owners plumb a bypass to get around the tight spacing, which adds friction and cost to the install.
Where it falls short
Temperature sensors and main boards are reported failing around 18 months on some units, and owners are blunt about warranty claim handling being a frustrating process.
Low pH water is the most common self-inflicted failure. Pool forum posts on this line repeat that water chemistry decides how long the exchanger lasts more than anything else.
3. Varpoolfaye 65000 BTU Inverter Heat Pump – Best Running Cost
Varpoolfaye 65,000 BTU Inverter Pool Heat Pump for Inground Pools 220V
65000 BTU inverter heat pump
COP 6.6 efficiency
45 dB(A) operation
Up to 21000 gallons
Pros
- Very quiet at 45 dB
- Heating and cooling both work well
- Factory-fitted 1.5 inch adapters and power cord
- Responsive customer support
Cons
- Roughly 1 degree per hour
- Adapters reported loose out of the box
- Condensation drainage surprises first-time owners
This is the heater we would put on a mid-size inground pool if running cost is the deciding factor. A COP of 6.6 means roughly six and a half units of heat for every unit of electricity, and it handles freshwater and saltwater.
Owners consistently call out the 45 dB(A) noise level as the standout. Several report the unit is effectively inaudible next to a filter pump, which matters if your equipment pad sits near a patio or a neighbor’s fence line.
It heats and cools. Owners in warm climates hold pools in the mid-80s through summer heat using the cooling mode, which turns a seasonal tool into a year-round one.
Hookup is genuinely quick: factory-installed 1.5-inch PVC adapters, a 118-inch power cord, and a water-electric separation design that keeps the electrical side away from the wet plumbing.
What you need to check before ordering
Manage expectations on speed. Owners report roughly 1 degree per hour, and a 20-degree cold-weather jump is not realistic. This heater holds temperature far better than it heats a cold pool quickly.
Confirm you have a 220V circuit with enough amperage for a hardwired install, and plan on using a fitted pool cover in cool weather.
Where it falls short
Factory-installed water adapters have been reported loose out of the box, causing first-start leaks. Check the fittings and tighten them before the first run.
Condensation dripping from the base of the unit is normal during heat exchange and defrost, but it surprises first-time owners and is worth knowing in advance.
4. Hayward HeatPro 140000 BTU Heat Pump – Best for Saltwater and Coastal Pools
Hayward HeatPro Pool Water Heat Pump Heater for Inground Pools, 140,000 BTU
140000 BTU air-source heat pump
Titanium heat exchanger
Ultra Gold corrosion protection
320 pounds
Pros
- Titanium exchanger built for salt and chemicals
- Non-corrosive design for coastal homes
- Holds temperature cheaper than gas
- Deep dealer and service network
Cons
- Highest unit cost in the roundup
- 320 pounds requires a crew
- Cannot heat effectively in cold air without a cover
The titanium heat exchanger is the reason to look at this unit. Hayward specifies titanium with Ultra Gold corrosion-resistant technology and UV-resistant body panels, which is the right answer for a saltwater pool or a house within a mile of surf.
Hayward positions this for in-ground pools used regularly, which is exactly the job an inground pool heater should do. Rather than blasting temperature from cold, it maintains a set point economically, and that is where the operating savings come from.
Capacity is generous at 140,000 BTU, which puts it in range for a large inground pool or a pool with a spa. Pool forum discussion on this category notes that the largest pool heat pumps generally top out around 140K BTU, so this sits at the practical ceiling.
Owner ratings sit at 4.1 across 114 reviews with a 14 percent 1-star share, and those negatives cluster around installation and components rather than heating performance.
What you need to check before ordering
This is the heaviest unit here at 320 pounds and it needs a dedicated electrical supply, so budget for professional installation and adequate pad space.
Confirm the ambient temperature in your coldest swimming months. Heat pumps lose effectiveness below roughly 50 to 60 degrees F, and owners in places like upstate New York and Delaware are already seeing 60-degree nights when they want heat.
Where it falls short
It carries the highest unit cost of anything in this roundup, and the weight means you are paying for craned-in installation on top of the equipment.
Without a fitted pool cover, cold-weather heating is a losing proposition. Pair it with a solar blanket or accept a shorter effective season.
5. Raypak 406000 BTU Propane Heater – Best for Propane-Only Homes
Raypak 406,000 BTU Digital Electronic Ignition Propane Pool Heater
406000 BTU propane
Copper fin-tube heat exchanger
Microprocessor thermostat
349 pounds
Pros
- Faster heat recovery than any other unit here
- Copper exchanger with stainless steel tube sheet
- Quiet for a burner this size
Cons
- 349 pounds needs professional handling
- Warranty depends on distant dealers
- Propane fuel cost is high ongoing
If your home has no natural gas line, propane is the fastest route to hot water and this is the strongest propane option here. At 406,000 BTU it is tied for the highest output in the roundup, and one owner measured a 9-degree temperature rise across the unit.
The heat exchanger is a copper fin-tube design with a stainless steel tube sheet, and the cabinet carries PolyTuf powder coating with polymer headers for corrosion resistance in a wet pad environment.
The microprocessor thermostat is precise and set-and-forget. Owners report it heated an 8×16 spa from 60 to 100 degrees in about 3 hours, which shows how much of the output is usable.
Replacement installs are clean. Owners swapping an older Raypak propane unit report matching fittings and hardware included, so the plumbing largely stays as-is.
What you need to check before ordering
Confirm your propane service can carry the load, and that you have a code-compliant gas line run. Connections are 2 inch CPVC with burner tray and fire tile included.
Ask the dealer where the nearest authorized service point is. That distance is the practical warranty question on this unit.
Where it falls short
At 349 pounds it is the heaviest thing we tested to move and needs professional handling. Warranty and dealer support are reported as unresponsive on failures, which is a real risk on a large combustion appliance.
Only 43 reviews means less long-term reliability data than the Hayward and Raypak natural gas units. Propane running cost is among the highest of any heater in this roundup.
6. NATURAQUELL 55000 BTU Full Inverter Heat Pump – Best Warranty and Cold-Weather Range
Inverter Pool Heat Pump, Up to 16,000 Gallons, Above/Inground Pools
55000 BTU/h full inverter
COP up to 16.00
Heats at 5 degrees F ambient
8-year warranty
Pros
- Longest warranty in the roundup at 8 years
- Heats at outdoor air as low as 5 degrees F
- No 1- or 2-star reviews posted
- Adjustable 2 inch connectors
Cons
- Only 16 reviews posted
- 55000 BTU caps it near 16000 gallons
- Saltwater compatibility not confirmed
The 8-year warranty is the standout here, four times what the shortest warranty in this roundup offers. That matters on a full-inverter unit where the compressor is the expensive failure.
Full inverter modulation is the difference here. Instead of cycling on and off, the compressor adjusts output continuously as the water approaches set temperature, which smooths out temperature swings and cuts energy use.
The claimed COP of up to 16.00 is the highest figure listed in this roundup, and the operating range is unusually wide: heating from 5 degrees F to 104 degrees F outdoor air, cooling from 59 degrees F to 109.4 degrees F.
It also heats and cools, with automatic 4-way valve defrost, a titanium heat exchanger, IPX4 protection and a 52 dB(A) rating. Adjustable 2-inch connectors accept common 1.25-inch and 1.5-inch hose, and the package includes a drain pipe, connector and four rubber shock absorbers.
What you need to check before ordering
Size it honestly. At 55,000 BTU per hour this is built around pools up to roughly 16,000 gallons, and under-sizing is the most common regret we saw in owner discussions of small heat pumps sold online.
Confirm saltwater compatibility with the manufacturer before buying. A titanium exchanger is claimed for corrosion resistance, but the listing does not confirm salt use the way some competitors do.
Where it falls short
Only 16 reviews is a thin base, and all 16 are 4 or 5 star. Perfect early scores tell you less about year five than a 4.1 average across 114 reviews does.
Full feature access depends on the Smart Life app or the on-unit touch panel, which is fine for most owners but adds a dependency some DIY installers dislike.
7. Raypak 406000 BTU Natural Gas Cupro Nickel Heater – Best Corrosion-Resistant Gas Option
Raypak 406,000 Btu Digital Natural Gas Pool Heater with Cupro Nickel
406000 BTU natural gas
Cupro-nickel heat exchanger
Pagoda airflow design
One-year warranty
Pros
- Cupro-nickel resists corrosion better than copper
- Very fast heat recovery
- Pagoda airflow works in harsh weather
- Built-in digital thermometer
Cons
- Only a one-year manufacturer warranty
- High fuel consumption by design
- Some LCD panels reported blank after install
Cupro-nickel is the material to ask about if you want a gas heater in a mildly aggressive water environment. It resists corrosion better than plain copper, which matters more than brand loyalty over a decade of service.
Heat speed is the headline. One 35,000-gallon inground owner went from 80 to 84 degrees in under two hours, and other owners describe the burner as quiet relative to its 406,000 BTU output.
The Pagoda airflow design keeps the heater active in harsh weather rather than shutting down when wind or cold enters the equipment pad, which is a real advantage in exposed installations.
The digital thermometer display removes the need for a separate pool thermometer, and the microprocessor thermostat handles the rest. Owners replacing earlier Raypak units report familiar controls and straightforward hookups.
What you need to check before ordering
Confirm natural gas availability at the pad. Self-installation on a gas unit needs gas line, plumbing and electrical competence, and a licensed fitter is the sensible call.
Ask the installer to power the unit through a full start-up cycle before signing off, because some units reported an LCD panel blank or non-start condition after installation that needed a reset.
Where it falls short
A one-year manufacturer warranty is short relative to the service life buyers expect from a 406,000 BTU appliance. That is the single biggest reservation here.
Owners acknowledge the fuel consumption is the trade-off for fast heating. If you plan to hold a pool at 84 degrees for months, this is the wrong economics.
8. MICOE 100000 BTU Inverter Heat Pump – Best Support for Large Inground Pools
MICOE 100,000 BTU Inverter Pool Heat Pump for 26,000 Gallon Pools
100000 BTU inverter heat pump
Up to 26000 gallons
Heating and cooling modes
54 dB(A)
Pros
- 100000 BTU covers pools up to 26000 gallons
- Quiet variable-speed operation
- Heating and cooling both perform well
- Customer support repeatedly praised
Cons
- Wiring diagrams need clarification
- Flimsy electrical cover plate needs drilling
- Slow heating in cold weather
This is the unit to look at for a pool in the 16,000 to 26,000 gallon range. It is a 100,000 BTU inverter air-source heat pump, and pool forum consensus is that anything under 100K BTU is spa-scale rather than a real inground pool heater.
Owners report real results: a 15×30 semi-inground pool gained 24 degrees F in 48 hours, and Central Texas pools were held at 85 degrees through triple-digit weather using the cooling side.
Setpoints are wide, from 46 to 104 degrees F for heating and 45 to 82 degrees F for cooling, with automatic defrost for cooler conditions and a variable-speed fan at roughly 54 dB(A).
Customer support is the quiet strength. Owners describe clear written answers to wiring questions and replacement parts sent at no charge, and the unit can run automatically off pump pressure when wired through an existing control box.
What you need to check before ordering
Budget for a proper electrical install. Professional electrical installation is recommended, and the supplied wiring diagrams have been confusing enough that owners had to ask support for clarification.
The factory electrical cover plate is a flimsy plastic part. Owners drill it and fit waterproof conduit for a permanent install, so plan for that material.
Where it falls short
Heating is slow in cold weather. One owner measured a 68 to 80 degree pull across three cool nights, and reported running cost of 15 to 20 per day in cool conditions.
The titanium heat exchanger here is specified for freshwater pools, so this is not the saltwater choice. The 2-year parts warranty is also shorter than several rivals.
9. FibroPool FH255 55000 BTU Heat Pump – Best Compact Option
FibroPool FH255 Pool Heat Pump – 240V Electric – 55,000 BTU – Metal
55000 BTU heat pump
240V electric operation
Titanium heat exchanger
98 pounds
Pros
- Compact 55000 BTU capacity with a titanium exchanger
- All-weather enamel-coated steel cabinet
- About 98 pounds
- 240V operation avoids gas line work
Cons
- Smallest pool rating in the roundup at 10000 gallons
- Heavier mid-rating cluster than rivals
- No published COP or noise rating
The FH255 is a compact unit rated for pools up to 10,000 gallons, tied with the NATURAQUELL for the smallest capacity claim in this roundup. That covers a compact in-ground pool or a swim spa, and FibroPool also offers 35,000 and 70,000 BTU versions in the same family.
Two construction details set it apart. The titanium heat exchanger supports saltwater and chemically treated pools, and the enamel-coated metal chassis is more weather-resistant than the plastic cabinets common on cheaper heat pumps. That makes it a straightforward fit for a saltwater system without a gas line.
At 98 pounds it is one of the lighter units in this roundup and easy to reposition, which matters on a cramped equipment pad.
Running on 240V means no gas line work and no propane, which removes the most expensive part of a gas heater installation for many owners.
What you need to check before ordering
Measure your pool properly. Owners repeatedly warn that low-BTU listings online are designed for small pools, and 55,000 BTU will feel undersized on a 16×32 inground basin.
The digital control panel allows precise temperature adjustment, and because it has no published COP or noise rating you cannot compare its efficiency directly against the inverter units above.
Where it falls short
Ratings are mid-clustered rather than polarised: 70 percent 5-star but 9 percent 3-star and 7 percent 2-star, a heavier spread of lukewarm feedback than the Hayward or Raypak units. It also carries the lowest capacity figure on this list at 55,000 BTU.
No warranty length is stated in the listing, and heat pumps are ineffective in cold weather without a pool cover. Budget for both.
10. Varpoolfaye 140000 BTU Inverter Heat Pump – Best for 30000 Gallon Pools
Varpoolfaye 140000BTU Swimming Pool Heat Pumps Up to 42000 Gallons 220v
140000 BTU inverter heat pump
COP 12.8 efficiency
Up to 42000 gallons
47 dB(A)
Pros
- Largest pool capacity claimed at 42000 gallons
- COP 12.8 at this size
- 47 dB(A) near the quietest here
- No 1-star reviews among 59 ratings
Cons
- Heaviest unit here at 337 pounds
- Only 59 reviews
- Shares a model number with a much smaller unit
This is the only heat pump in the roundup listed for 42,000-gallon pools, and it pairs that capacity with a COP of 12.8. For a large commercial-style inground pool that nobody wants to buy gas for, it is the standout choice.
Owner ratings are 4.7 across 59 reviews with 81 percent at 5 stars and zero 1-star reviews.
At 47 dB(A) it carries the second-lowest published noise figure of the ten, just behind the 45 dB(A) inverter pump in this roundup, which matters on a large property where the pad is far from the house but close to a shared boundary.
Like its smaller sibling it handles heating and cooling, works on freshwater and saltwater, uses 1.5-inch connectors and 220V power, and offers inverter mode plus WiFi app scheduling.
What you need to check before ordering
Confirm pad space and electrical capacity. At 337 pounds it is the second-heaviest unit here and needs equipment and professional installation.
Verify you genuinely have a 40,000-gallon-plus pool. On a smaller inground basin this unit will cycle less efficiently than a mid-size inverter, and the extra capacity buys nothing.
Where it falls short
Fifty-nine reviews is a thin track record for an appliance this large, and the listing shares a model number with the much smaller 65,000 BTU Varpoolfaye unit, which makes parts matching confusing.
The app ecosystem is shared across Varpoolfaye units and some owners find scheduling options limited compared with the Hayward and MICOE apps.
How to Choose a Pool Heater for an Inground Pool
Gas, heat pump or solar: pick one
Gas heats fastest and costs the most per hour. A 400,000 BTU natural gas unit can add 20 degrees to a large inground pool overnight, but the fuel bill scales with every degree.
A heat pump moves heat rather than making it, so a COP of 5 or better means five units of heat per unit of electricity. It wins on running cost and loses on speed, and it struggles below about 50 to 60 degrees F ambient.
Solar panels use the existing circulation pump and cost almost nothing to run, but only add meaningful heat in peak summer sun. They pair well with a cover. Our guide to solar pool heater basics covers the collector sizing rules if you go that route.
Size by gallons, not square feet
Calculate gallons first: average depth times length times width times 7.5. A 16×32 pool at 8 feet average depth is roughly 30,700 gallons, and a 20×40 at the same depth is about 48,000 gallons.
For gas, 100,000 BTU per 10,000 gallons is the common starting point, so 16×32 lands near 300,000 BTU and 20×40 near 400,000 to 500,000 BTU. Forum users regularly see contractors quote 250,000 and 400,000 BTU for the same pool, which is why the gallons calculation matters.
For heat pumps, match the manufacturer gallon rating rather than doing your own BTU math, and prefer the larger of two units when you are between ratings. A heat pump works best run continuously at partial output, which is exactly what an inverter compressor does.
Saltwater changes the exchanger decision
A salt chlorinator raises the corrosion risk on every metal part in the water path. Titanium exchangers, as on the Hayward HeatPro, the MICOE, the FibroPool and the NATURAQUELL, are the safe choice. Cupro-nickel, as on the Raypak 406,000 BTU natural gas unit, is a step up from plain copper but not titanium.
No exchanger saves you from chemistry. Balanced pH and sanitizer levels decide service life more than any brand.
What installation actually costs you in effort
Gas installation means a licensed gas fitter, a fuel line run and a meter capacity check. Heat pump installation means a 220V or 240V circuit, sometimes a panel upgrade, and hardwiring. Either way, plumber and electrician labour routinely exceeds the unit cost on a first-time install.
Before the contractor arrives, confirm four things: pad clearance for service access, whether plumbing enters on the side you need, gas line reach or electrical panel capacity, and drain routing for heat pump condensate.
Pentair, Hayward and Raypak: what owners say
These three names dominate because they are what installers carry and service, not because of spec sheets. Pool owners overwhelmingly defer to the contractor recommendation, and Pentair MasterTemp and Hayward Universal H-Series come up most often in the same threads.
Pentair and Hayward are the safest defaults for parts availability. Raypak earns respect for serviceable components and drop-in replacements, which owners replacing 10 to 17 year old units value highly. Its weaker point is warranty claim handling on some units.
For an electric-only setup, brand reputation matters less than COP, titanium exchanger material and inverter control.
Frequently Asked Questions
How many BTU heaters do I need for a 16×32 pool?
A 16×32 inground pool at 8 feet average depth holds about 30,000 gallons, which calls for roughly 300,000 BTU of gas heater capacity. Heat pumps are sized by gallons instead: look for a unit rated for 30,000 gallons or larger, or step up to a 100,000 BTU inverter model. Always add about 10 percent if a spa spills into the pool.
What type of heater is best for a pool?
It depends on how you use the pool. Gas heats fastest and is best for large pools or short-notice warm-ups. A heat pump costs far less to run and is best for holding temperature through spring and fall in a moderate climate. Solar costs almost nothing to run but only works in strong summer sun. Most owners with both gas and a mild climate pair a heat pump for holding with gas for quick recovery.
What size pool heater do I need for a 30000 gallon pool?
For 30,000 gallons, target about 300,000 BTU from a gas heater, which is the range where Hayward, Raypak and Pentair gas units sit. For a heat pump, choose a 100,000 BTU inverter model rated for 26,000 to 30,000 gallons. Below roughly 100,000 BTU most electric listings are spa-scale and will feel slow on a pool this size.
What is the best pool heater for inground pools?
The Hayward H-Series 400,000 BTU natural gas heater is our top pick overall because of its output, self-diagnosing control panel and the depth of Hayward’s dealer network. If running cost matters more than speed, the Varpoolfaye 65,000 BTU inverter heat pump holds temperature at a fraction of the cost and runs at 45 dB(A). For saltwater or coastal homes, the Hayward HeatPro 140,000 BTU titanium-exchanger heat pump is the durable choice.
What is the average cost to install a heater in an inground pool?
Most of the cost is labour and site work, not the unit. Gas installs add a licensed fitter, a fuel line run and sometimes a meter upgrade. Heat pump installs add a 220V or 240V circuit, possible panel work and hardwiring. Budget for plumbing changes to bypass tight inlet and outlet spacing. Get a line-item quote that separates unit, fuel or electrical work, and labour.
Pros and cons of gas vs electric pool heaters
Gas pros: fast heat, large capacity, works in cold weather, no dependence on ambient air. Gas cons: highest fuel cost, combustion parts to service, exhaust venting and gas line work. Heat pump pros: COP of 5 or better means far cheaper operation, heating and cooling, quiet inverter operation, no fuel line. Heat pump cons: slow heating, reduced output below about 50 to 60 degrees F, and a dedicated electrical circuit required.
Final Verdict: Which Pool Heater Should You Buy?
For most inground pools, the Hayward H-Series 400,000 BTU natural gas heater is the best pool heater for inground pools you can buy today: real heat output, a self-diagnosing control panel, flexible connection routing and a dealer network that will still exist in a decade. If fuel cost is the number that bothers you, the Varpoolfaye 65,000 BTU inverter heat pump holds temperature for a fraction of the running cost at 45 dB(A). Saltwater and coastal owners should go titanium, which points to the Hayward HeatPro 140,000 BTU.
Calculate your gallons before you buy anything, get the quote itemised so you can see the labour separately, and fit a pool cover. That last step does more for your swim season than any heater on this list. These are the best pool heaters for inground pools in 2026, and the right one is whichever matches your gallons, your fuel access and your climate.