Hayward Universal H-Series review
The gas heater for a pool that does not need 400,000 BTU thrown at it. Hayward publishes plenty about it, and omits the one number a buyer would compare on.
Quick picks
The reviewed heater, its propane sibling, and the four alternatives it is genuinely competing with. Live prices come from the retail listings.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 |  The one being reviewed Hayward Universal H-Series 150,000 BTU Natural Gas Heater 150,000 BTU/hr of input, cupro nickel exchanger as standard, and about half the gas demand of a full-size heater. | A modest pool where the gas supply, not the heater, is the real constraint | |
| 2 |  The same heater on propane Hayward H-Series 150,000 BTU Propane Pool Heater Identical machine, different fuel and a different running cost. It is also the version with a live retail price. | An inground pool up to about 450 sq ft with no natural gas at the property | |
| 3 |  The one that publishes an efficiency figure Raypak Digital Natural Gas Pool Heater 336,000 BTU/hr and a stated 82%. Twice the fire, and the number Hayward does not give you. | Heating fast and occasionally, rather than holding a temperature | |
| 4 |  If you want full size Pentair MasterTemp 400 Natural Gas Pool Heater 400,000 BTU/hr. The heater to compare against when speed rather than gas supply is the constraint. | A full-size pool heated on demand, when you want the largest gas class | |
| 5 |  If running cost matters more than speed Hayward HeatPro Pool Heat Pump Hayward's own heat pump, at about $10.75 per million BTU delivered against roughly $28.36 for gas. | Lowest running cost per degree when you want real temperature control | |
| 6 |  Buy this first, whichever you choose Sun2Solar 1600 Series Ultimate Blue Solar Cover Sizing a gas heater for a pool that vents its heat overnight is how people end up with a bigger heater than they needed. | An inground pool you cover most nights, every season |
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
What Hayward publishes
Read from Hayward’s own product page for the W3H150FDN on 17 October 2026. This is a fuller specification than most of this category manages, which makes the one absence more conspicuous rather than less.
| Specification | What Hayward states |
|---|---|
| Heating capacity | 150,000 BTU/hr |
| Thermal efficiency | Not stated anywhere on the page |
| Heat exchanger | Standard cupro nickel |
| Corrosion | Excellent salt water and chemical corrosion resistance |
| Water flow rate | Min 20, Max 125 (the table does not state the unit) |
| Plumbing | 2 in x 2-1/2 in CPVC union connections |
| Electrical | 120/240V, 60 Hz single phase, circuit amps 5.5, max breaker 15 amps |
| Size and weight | 24 x 19 x 29.5 in, 135 lb |
| Emissions | Meets or exceeds SCAQMD Rule 1146.2 low NOx standards |
| Warranty | Parts 1 year. Labor: none |
The flow row is quoted exactly as published. Gallons per minute is the convention in this category and the numbers only make sense that way, but the page does not label it and we are not going to add a unit on Hayward's behalf.
Finding one: there is no efficiency figure
A gas heater’s thermal efficiency is the whole of its running-cost story. It is the fraction of the fuel you burn that ends up in the water, and it is the only specification that turns a BTU rating into a bill. Hayward’s page for this heater does not give one.
What the page does carry is a claim of savings of up to 18% — which is a figure about reduced pump run time, not about how much of the gas reaches the water. It is not a thermal efficiency rating and it cannot be used as one. An 84% figure circulated in retail copy for the older H150FDN part this supersedes; it does not appear for the current part, so we do not attach it. We cost this heater at the 82% we assume for any gas heater that publishes nothing, which works out at about $28.36 per million BTU delivered.
Finding two: a power rating that cannot be right
Hayward’s specification table lists, alongside the electrical rows, “Power: 44 kW”. That cannot describe this appliance, and the same table says why:
| Stated circuit amps | 5.5 A |
| Stated maximum breaker | 15 A |
| 5.5 A x 240 V | about 1.3 kW |
| Stated 'Power' | 44 kW |
44 kW on a 15-amp breaker is off by a factor of about thirty.
This is almost certainly a data-entry artifact rather than anything about the machine — a gas heater's electrical draw is just the blower and the controls, and 1.3 kW is the plausible figure. We flag it because a buyer reading that table has no way to know which row to trust, and because this site's job is to say when a published number does not hold up.
Finding three: the warranty is thin, and now on the record
One year of parts, no labor. That is worth stating plainly because this site has previously recorded that Hayward publishes nothing about heater warranty — for this model it does, and a single year on a four-figure appliance with a cupro nickel exchanger is at the shorter end of what this category offers. For contrast, the FibroPool heat pump states a Limited Lifetime warranty and TURBRO gives 2 years on the machine with 5 on the compressor, both on much cheaper units.
The exchanger, and the saltwater question
Cupro nickel as standard rather than as a paid upgrade is the genuinely good news here, and Hayward states “excellent salt water and chemical corrosion resistance” for it. On gas heaters cupro nickel is the corrosion-resistant option and on several competitors it costs extra, so having it fitted as standard is a real advantage on a salted pool.
The honest qualifier: our saltwater page argues titanium or nothing for heat pumps, and that standard does not transfer to gas. A gas heater’s exchanger is a fired copper-alloy assembly rather than a titanium coil in a shell; cupro nickel is the best of what the technology offers. What nobody can tell you from a specification is how it fares against your water chemistry over a decade, which is why that sits in the cannot-assess list below.
Speed, and who this heater is wrong for
| 20,000 gal x 8.33 lb x 10°F | 1,666,000 BTU into the water |
| 150,000 BTU/hr x 82% assumed | 123,000 BTU/hr delivered |
| 1,666,000 ÷ 123,000 | about 13.5 hours |
Most of a day — against roughly six hours for a 336,000 BTU heater.
Which is the trade this heater asks you to make. Half the gas demand, and nearly twice the time. Run your own volume through the heating time calculator.
So it is the wrong heater if what you want from gas is the thing gas is uniquely good at: heating a cold pool on demand, this afternoon. Buy it for the smaller gas supply, not for speed. If you want speed, the full-size gas heaters are the page; if you want running cost, a heat pump beats it by roughly two and a half times and is slower still.
One practical note on buying it
The natural-gas version is listed at retail but frequently carries no buy-box price, which is the normal pattern for a dealer-channel heater rather than a sign of anything wrong with it. The propane sibling, the W3H150FDP, does carry a live price. Both are in the table above, so you can see which has a figure today. Part numbering is also worth knowing: the current SKU is W3HS150FDN with the OmniX control, which replaces the older H150FDN you will still see in older reviews and remaining stock. Same heater class.
Every pick, in detail
What each one publishes, what is good and bad about it, and — the section this category usually omits — what we could not judge without owning one.
Hayward Universal H-Series 150,000 BTU Natural Gas Heater
The gas heater for a pool that does not need 336,000 BTU an hour thrown at it. At 150,000 BTU/hr of input it is under half the fire of a full-size unit, which costs you speed and buys you something people discover too late: a much smaller gas supply to feed. On a modest inground pool or a big above-ground one, that is often the difference between using the gas line you already have and paying to upsize it.
Best for A modest pool where the gas supply, not the heater, is the real constraint
| Rated input | 150,000 BTU/hrHayward publishes this as a BTU/hr rating, in the gas convention: fuel burned per hour, not heat delivered into the water. | Manufacturer |
|---|---|---|
| Current part number | W3HS150FDN, which Hayward's listing states replaces the H150FDNSame heater class, current SKU, with the OmniX control. The older H150FDN part number still appears in older reviews and stock. | Retail listing |
| Heat exchanger | Standard cupro nickelCupro nickel is the corrosion-resistant option on most gas heaters and a paid upgrade on some. Hayward lists it as standard on this one. | Manufacturer |
| Thermal efficiency | Not stated for the current W3HS150FDNConfirmed on Hayward's own product page, read 17 October 2026: there is no thermal efficiency percentage anywhere on it. The only efficiency-shaped figure is a claim of savings of 'up to 18%', which refers to reduced PUMP run time rather than to combustion. An 84% figure circulated in retail copy for the older H150FDN; it does not appear for the current part, so we no longer attach it and run this heater at the 82% we assume for gas generally. | Manufacturer |
| Water flow window | Min 20, max 125Quoted exactly as Hayward publishes it — the specification table does not state the unit, though gallons per minute is the convention and the figures only make sense that way. Hayward advises keeping flow above the minimum with allowance for a dirty filter, to protect the exchanger. | Manufacturer |
| Connections | 2 in x 2-1/2 in CPVC unions | Manufacturer |
| Electrical | 120/240V, 60 Hz single phase, 5.5 circuit amps, 15 A max breakerHayward's table also carries a 'Power: 44 kW' row, which cannot describe this appliance: 5.5 A at 240 V is about 1.3 kW, and 44 kW would not sit behind a 15-amp breaker. We read it as a data-entry artifact and flag it rather than repeat it. | Manufacturer |
| Warranty | 1 year parts, no laborAt the shorter end of this category. For contrast, FibroPool states a Limited Lifetime warranty and TURBRO gives 2 years on the machine with 5 on the compressor, both on much cheaper units. | Manufacturer |
| Cost per million BTU delivered | About $28.36 at our 82% assumptionUS average residential natural gas at $24.09/Mcf (EIA, June 2026) divided by 82%, the same assumption we apply to every gas heater without a published efficiency figure. | Our arithmetic |
- Roughly half the gas demand of a full-size heater, which is often what decides the install
- Cupro nickel heat exchanger listed as standard rather than as an upgrade
- Low NOx certified, so it is permitted in the air districts that require it
- Slow for a gas heater: about 14 hours to lift 20,000 gallons ten degrees
- Still gas, so still roughly two and a half times a heat pump's cost per delivered BTU
- Hayward publishes no thermal efficiency figure for it on its own product page
- The thermal efficiency it actually delivers — no figure is published for the current part
- How the cupro nickel exchanger holds up against your water chemistry
- Whether your gas meter and line can feed it without an upgrade
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
Hayward H-Series 150,000 BTU Propane Pool Heater
The propane sibling of the natural-gas H150FDN this site already ranks, and the sensible starting point for a pool with no gas line. Hayward rates it for pools and spas up to 450 sq ft, and it takes water, gas and electrical connections on either side, which is the detail that decides how bad the plumbing day is. Read the running cost before the purchase price: propane delivers the same heat as natural gas at roughly three times the cost per BTU.
Best for An inground pool up to about 450 sq ft with no natural gas at the property
| Rated input | 150,000 BTU/hrGas heaters are rated by fuel INPUT, not heat delivered. At the 82% thermal efficiency this site assumes, about 123,000 BTU/hr reaches the water. | Manufacturer |
|---|---|---|
| Pool size the maker names | Pools and spas up to 450 sq ft of surfaceHayward lists 600, 750 and 1,200 sq ft models above this one. Surface area, not gallons, is how this maker sizes the range. | Manufacturer |
| Fuel | Propane (LP) | Manufacturer |
| Connections | Water, gas and electrical on either the left or right side | Manufacturer |
| Emissions | Low-NOx | Manufacturer |
| Size and weight | 29.5 x 19 x 24 in, 145 lb | Retail listing |
| Cost per million BTU delivered | About $35.66 on propaneUS average residential propane at $2.674/gal (EIA, week ending 30 March 2026) over 91,452 BTU/gal, divided by 0.82 thermal efficiency. The same heater on natural gas would be about $28.36. | Our arithmetic |
- No gas line needed — a propane tank goes where the truck can reach it
- Reversible connections, which is the difference between an easy install and a re-plumb
- Same H-Series platform as the natural gas model this site already ranks
- Propane costs roughly 26% more per delivered BTU than natural gas at national average prices
- A 150,000 BTU/hr burner empties a 100 lb cylinder in well under a day of continuous running
- Hayward publishes no thermal efficiency percentage on this listing
- The delivered propane price where you live, which is the number that decides everything
- Heat exchanger life on your water chemistry
- Whether your tank regulator can actually supply the burner at full rate
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
Raypak Digital Natural Gas Pool Heater
The right answer when speed matters more than running cost — a weekend pool you want warm on Friday afternoon rather than one you hold at temperature all season. At the assumptions we publish, gas costs roughly two and a half times what a heat pump costs per delivered BTU, and it will get there in a fifth of the time. Buy the speed if you need the speed.
Best for Heating fast and occasionally, rather than holding a temperature
| Type | Natural gas or propane fired, digital controlThe manufacturer publishes no retrievable specification sheet; figure is as listed at retail. | Retail listing |
|---|---|---|
| Rating convention | Rated by BTU/hr INPUTA 400,000 BTU gas heater burns 400,000 BTU an hour and delivers roughly 82% of it. Do not compare that number directly against a heat pump's output rating. | Published standard |
| Cost per million BTU delivered | About $28.36 at our published assumptionsUS average residential natural gas at $24.09/Mcf (EIA, June 2026) and an assumed 82% thermal efficiency. | Our arithmetic |
- Fast — hours rather than most of a day on a full-size pool
- Works the same in cold air, unlike a heat pump
- Lower purchase price than a heat pump of equivalent real output
- Roughly two and a half times a heat pump's cost per delivered BTU
- Needs a gas line sized for it, which is often the real cost
- Propane instead of natural gas raises the running cost by about a quarter again
- The efficiency this specific unit achieves in service
- Heat exchanger life against your water chemistry
- Whether your existing gas supply can feed it without an upgrade
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
Pentair MasterTemp 400 Natural Gas Pool Heater
The third name in every gas-heater comparison, and the one the listings describe as the quiet one. It is a 400,000 BTU/hr input heater, low-NOx certified, which puts it in the same class as the biggest Raypak — and therefore in the same speed bracket: hours rather than a day. Pentair does not state a thermal efficiency percentage in the listings we read, so we run it at the 82% we assume for gas generally.
Best for A full-size pool heated on demand, when you want the largest gas class
| Rated input | 400,000 BTU/hrGas convention: fuel burned per hour, not heat delivered. Delivered heat is this figure times the thermal efficiency. | Retail listing |
|---|---|---|
| Emissions | Low NOx certified | Retail listing |
| Thermal efficiency | Not stated as a percentage in the listings we readThe listings say best-in-class efficiency without a number. We run it at 82%, the assumption we use for every gas heater on the site, and would revise it if Pentair published a figure we could cite. | Retail listing |
| Cost per million BTU delivered | About $28.36 at 82% efficiencyUS average residential natural gas at $24.09/Mcf (EIA, June 2026). | Our arithmetic |
- Largest common residential gas class, so the fastest heat-up on this site
- Low NOx certified, so it is permitted in the air districts that require it
- Described across listings as noticeably quieter than the older gas designs
- Roughly two and a half times a heat pump's cost per delivered BTU
- 400,000 BTU/hr demands a gas supply most houses were not piped for
- No thermal efficiency percentage in the listings, so the efficiency claim is unverifiable
- Real delivered efficiency in service
- Heat exchanger life against your water chemistry
- Whether your gas meter and line can feed it without an upgrade
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
Hayward HeatPro Pool Heat Pump
If you are heating a pool with electricity, this is the shape of machine to do it with. A heat pump moves heat instead of making it, and at the assumptions we publish it delivers a million BTU into the water for about a fifth of what an electric resistance heater costs to deliver the same. It is slower than gas and it fades as the air gets colder, which is exactly when you want it — that trade is the whole decision.
Best for Lowest running cost per degree when you want real temperature control
| Type | Air-source heat pumpThe manufacturer publishes no retrievable specification sheet; figure is as listed at retail. | Retail listing |
|---|---|---|
| Rating convention | Rated by BTU/hr OUTPUTThis is the trap in the category. Gas heaters are rated by fuel INPUT, heat pumps by heat OUTPUT. A 140,000 BTU heat pump and a 140,000 BTU gas heater do not deliver the same heat. | Published standard |
| Cost per million BTU delivered | About $10.75 at our published assumptionsUS average residential electricity at 18.34 cents/kWh (EIA, June 2026) and an assumed COP of 5.0. Both are substitutable on our running-cost calculator. | Our arithmetic |
- Cheapest running cost per delivered BTU of any controllable heater
- No gas line, no combustion, no flue
- Holds a set temperature rather than depending on the weather
- Slow — expect most of a day to move a full-size pool ten degrees
- Efficiency falls with air temperature, so it is weakest in the shoulder season
- High purchase price against a gas heater of comparable output
- The COP this specific unit achieves at your conditions
- Compressor and control-board longevity
- Noise at the distance your deck actually sits from it
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
Sun2Solar 1600 Series Ultimate Blue Solar Cover
The cover to buy if you intend to keep using it in five years. 16 mil is the thickest tier the category sells, and thickness on a solar cover buys durability rather than heat — Bob Vila measured every cover in its hands-on group at the same 4 to 5 degrees, from 12-mil clear to 16-mil blue. Pay the extra for the one that survives being dragged over the coping twice a day, not for a temperature difference that did not show up in the only published one-hour test in this category.
Best for An inground pool you cover most nights, every season
| Price shown for | 24 ft roundThis product is sold in several sizes on one listing. The live price and photograph on this page are the ones Amazon returns for this variant; other sizes are priced separately. | Retail listing |
|---|---|---|
| Thickness | 16 milThe manufacturer publishes no retrievable specification sheet; figure is as listed at retail. | Retail listing |
| Color | Blue | Retail listing |
| Stated lifespan | 5 to 10 years for the 16-mil tierSwim University's published figure for 16-mil covers generally, not a Sun2Solar warranty statement. | Retail listing |
| Bubble side | Bubbles face the waterCategory-wide instruction, not brand-specific. The bubbles are the insulating layer and they have to touch the water. | Published standard |
4 to 5 degrees F in one hour
Claimed by Bob Vila, measured across all covers in their group. Conditions: One hour under 2pm sun on 89 to 92 degree F days. Source
Their figure was the same for every cover they put on the water. Read our reconciliation of what a one-hour reading actually measures before you plan around this number.
- Thickest tier sold, which is where the durability difference actually is
- Blue absorbs more of the incoming energy at the surface than clear does
- Cuts oversize to your pool shape with household scissors
- Heavy and awkward at 16 mil — a large inground cover is genuinely a two-person job without a reel
- Costs meaningfully more than the 12-mil version for no measured heating advantage
- Whether the seams hold up over five seasons of daily handling
- How the bubble layer survives repeated dragging over rough coping
- Whether the stated lifespan tier holds for this specific product line
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
Questions people actually ask
What is the Hayward Universal H-Series' efficiency?
Is the Universal H-Series good for a saltwater pool?
Is 150,000 BTU enough for my pool?
What is the difference between H150FDN and W3HS150FDN?
Why is there often no price on the natural-gas version?
What flow rate does it need?
- Hayward's own product page for the Universal H-Series W3H150FDN: heating capacity 150,000 BTU/hr, "Standard cupro nickel heat exchanger", "Excellent salt water and chemical corrosion resistance", Water Flow Rate Min 20 and Max 125 (the table does not state the unit), 2 in x 2-1/2 in CPVC union plumbing connections, 24 x 19 x 29.5 in, 135 lb, 120/240V 60 Hz single phase, circuit amps 5.5, maximum breaker 15 amps, a "Power: 44 kW" row that cannot be reconciled with that breaker size, warranty of 1 year parts and no labor, SCAQMD Rule 1146.2 low-NOx compliance, and no thermal efficiency figure anywhere on the pageHayward Industries · read 2026-10-17
- Hayward W3H150FDP listing: 150,000 BTU propane, rated for pools and spas up to 450 sq ft, low-NOx, reversible left/right water, gas and electric connections, 145 lbHayward, as listed at retail · read 2026-09-20
- Average retail price of electricity to US residential customers: 18.34 cents/kWh, June 2026U.S. Energy Information Administration · read 2026-09-02
- US residential natural gas price: $24.09 per thousand cubic feet, June 2026U.S. Energy Information Administration · read 2026-09-02
- US residential propane price: $2.674 per gallon, week ending 30 March 2026U.S. Energy Information Administration · read 2026-09-02
- Energy content conversion factors: 3,412 BTU per kWh, 1,036 BTU per cubic foot of natural gas, 91,452 BTU per gallon of propaneU.S. Energy Information Administration · read 2026-09-02
- U.S. Department of Energy pool-energy figures (evaporation share, BTU per pound evaporated, cover savings, recommended temperatures, wind effect)Recreonics, reproducing and attributing the U.S. Department of Energy · read 2026-09-02
- Pool heater roundup: the 8.33 BTU per gallon per °F figure, attributed on the page to Alicia Toedter of Leslie'sBob Vila · read 2026-09-02
#ad Where a retailer’s listing is cited above as the source of a published specification, that link is an affiliate link, at no extra cost to you. Independent sources and manufacturer documentation are never wrapped and earn nothing. How this site is funded.
Every URL above was fetched and returned content on the date shown. Where a figure is ours rather than somebody else’s, the arithmetic is on the page and on the methodology page. If you find an error in it, we would genuinely like to know.
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