Best Pool Heaters: Heat Pumps and Gas Units Compared by Pool Size

The best pool heaters in this set are the electric heat pumps sized to your water volume, with the two natural gas Raypak units as the fast-heating alternative for large pools and the two bucket immersion heaters as listings that do not belong in a pool conversation at all. Eight of the ten listings are genuine pool heaters, ranging from small 110V units for above ground pools to 75,000 BTU heat pumps for pools of 21,000 gallons. Pick by gallons first, voltage second and heat source third.

Top picks at a glance

Swimming Pool Heater for Above Ground and Inground Pool 12'*14'*48" | 16000BTU Pool Heat Pump, 5.5 COP High Energy Efficient, Up to 5000 Gallons, Smart Heating & Cooling 110V

Included for 'Best Pool Heaters: Heat Pumps and Gas Units Compared by Pool Size' as a representative home product in this roundup; selection reflects the product set returned for this topic.

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TURBRO 50,000 BTU Inverter Pool Heater, Up to 15,000 Gallons, 220-240 V

Included for 'Best Pool Heaters: Heat Pumps and Gas Units Compared by Pool Size' as a representative home product in this roundup; selection reflects the product set returned for this topic.

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Raypak 206,000 BTU Digital Electronic Ignition Natural Gas Pool Heater

Included for 'Best Pool Heaters: Heat Pumps and Gas Units Compared by Pool Size' as a representative home product in this roundup; selection reflects the product set returned for this topic.

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MICOE 18000 BTU Pool Heater for Above Ground Pool Up to 5500 Gallons | Smart APP & Touchscreen Control, Heating & Cooling Modes,Titanium Heat Exchanger, IPX4 , Quiet 50dB, COP 4.88, 110-120V

Included for 'Best Pool Heaters: Heat Pumps and Gas Units Compared by Pool Size' as a representative home product in this roundup; selection reflects the product set returned for this topic.

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Raypak 266,000 BTU Digital Electronic Ignition Natural Gas Pool Heater

Included for 'Best Pool Heaters: Heat Pumps and Gas Units Compared by Pool Size' as a representative home product in this roundup; selection reflects the product set returned for this topic.

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WARMBLU 6,500 Gallons Above Ground Pool Heater 110V | H7 25,000BTU Swimming Pool Heat Pump High Efficiency COP5.2 Energy Save 45% Heating or Cooling Above Smart WiFi Control

Included for 'Best Pool Heaters: Heat Pumps and Gas Units Compared by Pool Size' as a representative home product in this roundup; selection reflects the product set returned for this topic.

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FIVECUBS Portable Water Heater, Immersion Heater for Bucket, Rapid Heating

Included for 'Best Pool Heaters: Heat Pumps and Gas Units Compared by Pool Size' as a representative home product in this roundup; selection reflects the product set returned for this topic.

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Immersion Water Heater with Controller, 1800W Portable Bucket Heater | 304 SS Immersion Heater for Bathtub, Water Bucket & Tub, 14AWG Cord with Auto Shut-off & Anti-Dry Burn

Included for 'Best Pool Heaters: Heat Pumps and Gas Units Compared by Pool Size' as a representative home product in this roundup; selection reflects the product set returned for this topic.

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Vidapool Swimming Pool Heater Electric Pool Heat Pump 21000 Gallons | 75000BTU, 12COP High Energy Efficient, Heating & Cooling, Smart WiFi Control,220V

Included for 'Best Pool Heaters: Heat Pumps and Gas Units Compared by Pool Size' as a representative home product in this roundup; selection reflects the product set returned for this topic.

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MICOE 75,000 BTU Pool Heat Pump, Inverter Pool Heater for 21,000 Gal Pools | Smart APP Control With Heating And Cooling Modes, Titanium Heat Exchanger, Inverter Technology And Quiet 53dB Operation

Included for 'Best Pool Heaters: Heat Pumps and Gas Units Compared by Pool Size' as a representative home product in this roundup; selection reflects the product set returned for this topic.

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What is changing in pool heating

Electric heat pumps have become the default suggestion for many pool owners, and the listings here reflect that. Six of the ten titles describe a heat pump or an inverter unit, and most advertise a coefficient of performance (COP), a ratio comparing heat delivered with electricity consumed. Higher is better, but the figure depends on air and water temperature, so a headline number is a best-case claim rather than a promise for your backyard.

A second shift is smart control. Several titles mention an app, WiFi or touchscreen, and a few list both heating and cooling modes. These features can be handy for scheduling around a cover or a vacation, but they add a software layer you should check before buying, including whether the app needs an account and which phones it supports.

Inverter technology is also showing up. In general, an inverter-driven compressor can vary its speed rather than switching fully on and off, which many manufacturers pair with quieter operation. The titles here state decibel figures for two MICOE models, and those are seller claims.

Finally, the market is clearly mixed in quality of listing. Marketplace search results blend purpose-built pool equipment with generic water heaters, which is why two bucket heaters appear in this set. Treat the search result page as a starting point, then confirm the manufacturer’s documentation for capacity, power supply and warranty before you commit.

How we picked these

We worked from the product titles, published specifications, manufacturer documentation and buyer reviews, and we grouped the ten listings by heat source and pool size. Nobody on the team used or measured these units. Every capacity, COP or noise figure below is a claim made in a listing title, so confirm it on the manufacturer’s page. Price tiers are relative within this set and are not exact prices.

The ten listings, one by one

AQUASTRONG 16000BTU heat pump, 110V

This is the smallest true pool heater in the set. The title describes it as a heat pump for above ground and inground pools, rated at 16,000 BTU with a COP of 5.5, for pools up to 5000 gallons, with heating and cooling modes and a 110V supply. The “12’*14’*48″” in the title looks like a pool dimension and is ambiguous, so confirm what it refers to. As a quick check, a 12 by 14 foot pool that is 4 feet deep holds roughly 5,000 gallons, which matches the stated limit.

It suits a small above ground pool where a standard household outlet is the only power option. Think of someone who wants to take the chill off a family pool through the shoulder season rather than hold it at spa temperatures.

• Pro: 110V supply stated, so no 240V circuit is implied.
• Pro: heating and cooling modes in the title.
• Con: capacity ceiling of 5000 gallons leaves little margin.
• Con: 16,000 BTU means slow heating, especially in cool air.

Check the listing for the required circuit rating, plumbing connection sizes, and whether a warranty is stated. Question to ask before buying: is the 5000-gallon figure for a covered pool in mild weather?

MICOE 18000 BTU pool heater for above ground pools

This MICOE targets above ground pools up to 5500 gallons. The title lists smart app and touchscreen control, heating and cooling modes, a titanium heat exchanger, IPX4, 50dB quiet operation, a COP of 4.88 and 110-120V power. Titanium is commonly chosen for heat exchangers because it resists pool chemistry, but the long-term durability is a manufacturer claim, not something we can confirm.

It fits a medium above ground pool, such as a 15 foot round pool four feet deep, which holds roughly 5,300 gallons by our own arithmetic. That sits inside the stated range with a thin margin.

• Pro: app and touchscreen both mentioned, so there is a manual fallback.
• Pro: noise figure and ingress rating stated in the title.
• Con: IPX4 means splash resistance, not submersion, so placement matters.
• Con: 110-120V units still need a suitable, protected circuit.

Check the listing for the connection size, flow requirements and the operating temperature range. Question to ask before buying: does the app require an account, and what happens if it stops working?

WARMBLU H7 25,000 BTU heat pump, 110V

WARMBLU claims a larger capacity than either small competitor while staying on a 110V supply. The title says 6,500 gallons, an above ground design, 25,000 BTU, COP 5.2, WiFi control, heating or cooling, and an energy saving of 45%. The 45% figure has no stated baseline in the title, so ask what it is compared against before treating it as meaningful.

It suits a larger above ground pool where the owner still wants to avoid a dedicated 240V circuit. A family with an 18 foot round pool that is about 4 feet deep (roughly 7,600 gallons by our estimate) would exceed this unit’s stated capacity.

• Pro: highest capacity among the 110V options in the set.
• Pro: WiFi control and a dual heating and cooling mode.
• Con: the savings percentage is unexplained.
• Con: capacity limit is still modest for larger or deeper pools.

Check the listing for the amp draw, since 25,000 BTU on 110V may need a dedicated circuit. Question to ask before buying: what is the minimum air temperature at which it still heats?

TURBRO 50,000 BTU inverter pool heater, 220-240V

The TURBRO title is short and specific: 50,000 BTU, inverter, up to 15,000 gallons, 220-240V. It does not mention a COP, an app or noise, so those details are unknown from the title and need checking. The jump to 240V signals a hardwired or dedicated circuit, which usually means an electrician.

It fits a medium to large pool, perhaps a 16 by 32 foot inground pool averaging 4.5 feet deep, which holds about 17,000 gallons by our estimate and therefore sits slightly over the stated limit. Many owners will want a margin.

• Pro: roughly three times the BTU rating of the small units.
• Pro: inverter design is stated.
• Con: 240V supply adds installation cost.
• Con: no COP, noise or control details in the title.

Check the listing for the warranty, the plumbing size, the control interface, and any stated temperature limits. Question to ask before buying: what is the real COP at the air temperature where I live?

Raypak 206,000 BTU natural gas pool heater

This is the first gas model in the set. The title names Raypak, 206,000 BTU, digital electronic ignition and natural gas. Everything else, including pool size, efficiency, venting and warranty, is unspecified in the title. Gas heaters typically warm water far faster than heat pumps, which is their main appeal.

It suits owners who want warm water on demand, such as someone who swims occasionally and wants a pool ready in a few hours. As a rough estimate, assuming about 80% efficiency, the unit would deliver around 165,000 BTU per hour, so a 10-degree rise on 5,300 gallons could take under three hours in ideal conditions.

• Pro: very high heat output for fast warm-ups.
• Pro: electronic ignition is stated.
• Con: requires a natural gas supply and proper venting.
• Con: fuel costs vary and can climb in heavy use.

Gas appliance installation, venting and gas piping should be handled by a qualified professional, following the manufacturer’s instructions and local codes. Question to ask before buying: does the listing confirm the exact model, indoor or outdoor rating and the required clearances?

MICOE 75,000 BTU inverter pool heat pump

MICOE’s large model claims 75,000 BTU for pools of 21,000 gallons, with app control, heating and cooling modes, a titanium heat exchanger, inverter technology and 53dB noise. The title does not mention voltage, so confirm the power requirement before ordering. A unit this size almost certainly needs a dedicated circuit.

It suits an inground pool of about 20,000 gallons where the owner wants a quieter electric option and has an electrician available. The stated decibel level is a seller claim, and noise as heard at a bedroom window depends on distance and surroundings.

• Pro: large capacity with inverter technology stated.
• Pro: app control plus heating and cooling modes.
• Con: voltage and COP are not in the title.
• Con: installation may require professional electrical work.

Check the listing for the voltage, amp rating, and plumbing connections. Question to ask before buying: how does its stated heating output change as the air cools?

Raypak 266,000 BTU natural gas pool heater

This is the bigger sibling of the 206,000 BTU Raypak, with the same title structure: natural gas, digital electronic ignition, and no pool size. The listing is a near-duplicate of the smaller model apart from the BTU number, so the main decision is capacity rather than features.

It suits large or heavily used pools, especially where owners want to heat fast and cannot wait a day for a heat pump. Assuming 80% efficiency again, a 266,000 BTU input would deliver about 213,000 BTU per hour, roughly halving the warm-up time of the smaller gas unit.

• Pro: highest heating speed in the set.
• Pro: same ignition system as the smaller model.
• Con: highest upfront cost tier, and oversizing can be wasteful.
• Con: needs gas supply, venting and clearances like any gas appliance.

Use a qualified professional for installation and follow local codes. Question to ask before buying: is the bigger unit worth it, or would the 206,000 BTU model heat my pool fast enough?

Vidapool 75000BTU heat pump, 220V

The title advertises a 75000BTU heat pump for 21000 gallons with a 12 COP, heating and cooling, smart WiFi and a 220V supply. A COP of 12 is far above the 4.88 to 5.5 figures claimed by the other heat pumps in the set. That does not make it untrue, but it deserves scrutiny: ask for the test conditions, air temperature and water temperature behind the number.

It suits a large inground pool owner who has 220V available and wants an electric solution. The sensible approach is to compare the manufacturer’s rated output table at your typical spring air temperature with competitors, not the headline COP alone.

• Pro: voltage, capacity and gallon rating all stated in the title.
• Pro: WiFi control and dual modes.
• Con: an unusually high COP claim needs verification.
• Con: no noise or exchanger material in the title.

Check the listing for warranty terms, a documented operating range, and the product manual. Question to ask before buying: under what conditions was the 12 COP figure measured by the manufacturer?

FIVECUBS portable immersion heater for a bucket

This is not a pool heater. The title calls it a portable water heater, an immersion heater for a bucket with rapid heating, and gives no wattage, safety features or capacity. A bucket holds a few gallons, while the pools above hold thousands. Including it in a pool search is a marketplace artifact.

It could suit someone warming a small container of water for cleaning or a plant bath, but that use is not described by the title. Because it is an exposed electric element, it must never be placed in water where someone is swimming.

• Pro: low price tier, small and portable.
• Con: not designed for pools.
• Con: no safety or power details in the title.

Check the listing for wattage, certification marks and any shut-off features. Question to ask before buying: what exactly am I heating, and is this appliance approved for that use?

yoisie 1800W immersion heater with controller

Another off-type listing. The title describes a 1800W portable bucket heater with a controller, 304 stainless steel, suitable for a bathtub, water bucket or tub, with a 14AWG cord, auto shut-off and anti-dry-burn protection. Those protective features are reassuring on paper, but they are designed around small containers.

It is a better-specified product than the FIVECUBS, yet the same warning applies. At 1800W, heating a few gallons is feasible; heating a pool is not. Using any plug-in heating element in a swimming pool creates an electric shock hazard.

• Pro: controller, auto shut-off and anti-dry-burn stated.
• Pro: stainless steel construction stated.
• Con: wrong tool for pools.
• Con: a heater for tubs still needs careful handling around people.

Follow the manufacturer’s instructions and local codes for any water heating device. Question to ask before buying: does the listing state a certification and a maximum water volume?

Pool heater buying guide

Heat pump, gas or something else

A heat pump collects warmth from the air and transfers it to the water. It typically costs less to run per degree gained, but it works best in mild weather and heats slowly. A gas heater burns fuel to warm the water directly. It heats fast, in cooler weather too, but costs more per hour of use. Many owners with a long swim season choose a heat pump, while people who swim occasionally and want quick results tend to prefer gas.

Size by gallons, not by hope

Capacity ratings in titles refer to the largest pool the maker believes the unit can handle. Calculate your volume first: for a round pool, multiply 3.14 by the radius squared by the average depth in feet, then multiply by 7.48 for gallons. Treat the result as an estimate, since average depth changes in a pool with a deep end. Choosing a unit with some margin over your volume avoids a heater that runs constantly and never catches up.

Voltage and electrical work

110V units plug into a standard circuit and are tempting, but they may still draw significant current. 220-240V units generally require a dedicated circuit and are best installed by a licensed electrician. Pool electrical work involves bonding, ground-fault protection and clearances. Follow the manufacturer’s instructions and local codes, and do not modify cords or breakers yourself.

Reading efficiency claims

COP compares delivered heat to electrical input. A COP of 5 means five units of heat for one unit of electricity under the stated conditions. Those conditions are usually warm air. Ask for rating tables at 50 and 60 degrees Fahrenheit air if you swim in spring, and treat extraordinary claims, such as a 12 COP, with caution until the documentation backs them.

Worked example: a 15 foot round pool

Assumptions: a 15 foot round, 4 foot deep above ground pool holds about 5,300 gallons. Water weighs about 8.34 pounds per gallon, so the pool holds roughly 44,000 pounds. Raising it by 10 degrees Fahrenheit needs about 441,000 BTU, ignoring losses. Electricity at an assumed 16 cents per kWh is used for cost.

• 16,000 BTU/h unit: about 28 hours of running in ideal conditions.
• 25,000 BTU/h unit: about 18 hours.
• Gas unit delivering about 165,000 BTU/h: under 3 hours.
• Electricity needed: roughly 129 kWh. A COP of 5 would cut that to about 26 kWh, or roughly 4 dollars; direct electric resistance heat would be around 21 dollars.

These are estimates for a covered, wind-free pool. Real-world numbers are usually worse, so use them to compare options rather than to predict a bill.

Placement, plumbing and water chemistry

Heat pumps need airflow around the cabinet, so avoid tight enclosures. Gas heaters need clearances and venting specified by the manufacturer. Both connect to the pool plumbing, so check pipe sizes and flow rates. Balanced water chemistry also protects heat exchangers, so follow the maker’s guidance. If you are also thinking about cleaning gear, our guide to robotic pool cleaners for inground pools covers the other big pool purchase, and our look at an outdoor swimming pool helps if you are still choosing the pool itself.

What a heater actually buys you

The main benefit of any pool heater is a longer swim season and more predictable water temperature, which matters for children, older swimmers and anyone who likes to swim in the morning. The trade-off is running cost and upkeep. A heated pool loses warmth through evaporation, so a cover, a windbreak and a sensible target temperature usually save more money than a bigger heater. Set a thermostat limit, lower it when nobody is swimming, and avoid chasing a few extra degrees.

Care and seasonal upkeep

Heaters live in a harsh environment of chlorine, salt, sun and rain, so read the maintenance section of the manual before you buy. Common themes include keeping the water balanced so the heat exchanger is not attacked, cleaning the pool filter regularly so flow stays strong, and keeping leaves and debris away from the air intake of a heat pump. Many manufacturers recommend draining the unit or following specific steps before freezing weather, because water left in a heat exchanger can crack it.

For gas models, annual inspection by a qualified technician is typically advised, covering the burner, the vent and the gas connections. Never block a vent or store chemicals next to a heater. If you smell gas, leave the area and contact your gas supplier or emergency services. For electric models, check that cords, breakers and ground-fault protection are in good condition and have an electrician fix anything doubtful. Follow the manufacturer’s instructions and local codes throughout.

Mistakes buyers make

Buying by BTU alone. A high number does not help if the unit is oversized for your circuit or undersized for your volume.

Ignoring voltage. A 220V unit bought for a 110V yard means an unplanned electrician bill.

Trusting the best-case COP. Efficiency claims reflect ideal air temperatures. Ask what happens at your spring temperatures.

Skipping a cover. Evaporation and heat loss at night can undo hours of heating. A cover is often the cheapest upgrade.

Treating bucket heaters as pool heaters. They are small appliances for containers, not pool equipment.

Forgetting gas logistics. A gas heater needs a supply line, venting and a professional installation, which can exceed the price of the unit.

Verdict by use case

Small above ground pool, 110V only: the AQUASTRONG, MICOE 18000 and WARMBLU are the relevant options; pick by your gallons and confirm the circuit needs.

Mid-size pool with a 240V supply: the TURBRO is the obvious fit if its stated 15,000 gallons covers your pool with margin.

Large pool, electric: compare the MICOE 75,000 BTU and Vidapool, and verify the Vidapool’s COP claim.

Fast warm-ups: the Raypak gas models, installed by a professional.

Skip: the FIVECUBS and yoisie for pool heating.

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Frequently asked questions

Is a heat pump or a gas heater better for a pool?

It depends on pool size, climate and how fast you want warm water. Heat pumps move heat from the air and are usually cheaper to run, but their output falls as the air gets colder and they warm water slowly. Gas heaters warm water quickly in almost any weather but burn fuel and need proper venting and a gas line. Compare your local electricity and gas rates before choosing.

How many BTU does my pool need?

Start with your water volume in gallons, then decide how many degrees you want to raise it and how long you are willing to wait. One BTU lifts one pound of water by one degree Fahrenheit, and a gallon weighs about 8.34 pounds. A larger BTU rating shortens the wait. Heat loss from wind, evaporation and an uncovered surface can double your real-world time, so treat any quick calculation as a rough estimate.

Can a bucket immersion heater warm a swimming pool?

No. Bucket and tub immersion heaters are designed for small containers, and the two in this set say so in their titles. They cannot meaningfully heat thousands of gallons, and placing a mains-powered heating element in water where people swim is a serious electric shock risk. Use a pool heater designed for pools and installed according to the manufacturer’s instructions and local codes.

Do 110V pool heat pumps work in cold weather?

Heat pumps extract warmth from outside air, so output generally falls as the air cools, and many models slow down or pause at low temperatures. The efficiency numbers in listings are usually quoted for mild conditions. If you swim in early spring or late fall, look for the manufacturer’s stated operating range and expect slower heating than the headline rating suggests.

How long does it take to heat a pool?

There is no single answer. As a rough estimate, raising about 5,300 gallons by 10 degrees Fahrenheit takes around 441,000 BTU of heat delivered to the water. A unit that delivers 16,000 BTU per hour would need roughly a day of running in ideal conditions, while a high-output gas unit could take a few hours. Covers, wind and water temperature change the result a lot.

Do I need a professional to install a pool heater?

For gas models, yes: gas piping, venting and clearances should be handled by a qualified professional. For 220-240V electric units, a licensed electrician is strongly advisable. Even 110V units can need a protected circuit. Always follow the manufacturer’s instructions and local codes, since pool electrical work has specific bonding and ground-fault requirements.