Hayward Universal H-Series H250FDN Gas Pool Heater
An average-sized Florida pool, or a pool with a small spa, where you want gas-speed heat without paying for 400,000 BTU you will never use.
Gas heater
SKU H250FDN
- BTU input
- 250,000 BTU/hr
- Fuel / power
- Natural gas
- Thermal efficiency
- 84% thermal efficiency
- Heat exchanger
- Cupro-nickel
- Warranty
- Parts: 3 years · Labor: 1 year field labor (3 years when sold by a Hayward Rewards dealer)
- Controls & automation
- Onboard control pad with a two-digit temperature display and separate pool and spa setpoints; app control when connected to a Hayward Omni control system.
Modern Pool Heating Equipment Score
Our score for the equipment itself. It is not a Google or customer review rating.
How we rate heatersFull specifications
Every row below is taken from a manufacturer document. Anything the manufacturer does not publish is left out rather than estimated.
| Manufacturer product name | Universal H-Series Heater 250,000 BTU - Natural Gas, Low NOx |
|---|---|
| BTU input | 250,000 BTU/hr |
| Thermal efficiency | 84% |
| Fuel | Natural gas (H250FDP is the propane version) |
| Heat exchanger | Cupro-nickel, standard on all models |
| Emissions | Low NOx; meets SCAQMD Rule 1146.2 |
| Water connections | 2" x 2-1/2" CPVC unions |
| Gas connection | 3/4" NPT |
| Water flow | 25 GPM minimum, 125 GPM system maximum |
| Gas pressure (natural gas) | 4.5" w.c. minimum inlet, 10.5" w.c. maximum inlet, 2.0" w.c. manifold |
| Indoor vent pipe | 4" diameter (natural gas) |
| Clearances | 6" rear, 12" sides |
| Minimum operating temperature | 40°F |
| Electrical | Field-selectable voltage plug: 110-130 VAC, 2 A or 220-250 VAC, 1 A (240 VAC factory default). Hayward's product page lists 120/240V, 1 phase, 60 Hz, 5.5 circuit amps, 15 A maximum breaker. |
| Dimensions and weight | 24" H x 25" W x 29.5" L; 165 lb per the product page (the 2023 Universal H-Series brochure lists 134 lb for the same cabinet) |
| Certification | Certified by the Canadian Standards Association |
| Controls and automation | Onboard control pad with protective cover, two-digit display, separate pool (90°F default maximum) and spa (104°F default maximum) setpoints and a temperature lockout; controllable through a Hayward Omni control system. Two-wire and three-wire remote terminals are provided. |
Why homeowners consider it
- It carries the same 84% thermal efficiency as the 400,000 BTU model — the top figure in Hayward's own published table for the line — so stepping down in size costs you nothing in efficiency.
- The cupro-nickel heat exchanger is standard rather than an upgrade. On a salt pool or a coastal lot that is the single most useful thing about this heater, and Hayward's own brochure makes the point that other manufacturers charge hundreds of dollars for the same material.
- At 25 inches wide and 165 pounds on Hayward's product page — its 2023 brochure lists 134 pounds for the same cabinet — it is the size most crowded Sarasota equipment pads can actually take. The 400,000 BTU version is nine inches wider, which is often the difference between a drop-in swap and moving valves.
- 250,000 BTU/hr is the right amount of heat for a typical residential pool. Hayward's own sizing table puts the H250 at roughly 750 square feet of pool surface at a 30°F rise, and at about 29 minutes to raise a 400-gallon spa by 30°F.
- Front-panel-only service access and universal 2 inch by 2-1/2 inch CPVC union connections mean a technician is not pulling the unit away from a wall to reach the board, and a future swap does not mean re-plumbing the pad.
What to know before buying
- Natural gas has to be at the address. Large parts of Sarasota and Manatee County have no gas main, which pushes you to the propane H250FDP plus a tank and a delivery contract.
- The gas line back to the meter has to be sized for 250,000 BTU/hr through a 3/4 inch NPT connection. Hayward's Quick Reference Guide specifies a minimum inlet pressure of 4.5 inches w.c. and a maximum of 10.5 inches w.c. on natural gas; an undersized existing line is the most common reason a heater swap turns into a bigger job than the quote.
- It needs at least 25 GPM through the exchanger, with a 125 GPM system maximum. On a variable-speed pump the heating speed has to be programmed high enough to satisfy the water pressure switch, or you will see an LO code every time it tries to fire.
- Hayward specifies 6 inches of rear clearance and 12 inches on the sides, plus a minimum operating temperature of 40°F. Measure the pad before ordering.
- The labor side of the warranty depends on who sells it. Standard Expert Line coverage is 3 years parts and 1 year field labor; the 3-year labor term only applies when the heater comes through a Hayward Rewards dealer, and the W3-prefixed version sold online is an Open Line SKU with 1 year parts and no labor at all.
- This is the non-OmniX version. If you want app control and remote diagnostics built into the heater itself rather than through a separate Omni panel, the equivalent SKU is the HS250FDN.
Warranty, term by term
The warranty only matters on the parts that actually fail. Here is how this one splits up.
- Parts
- 3 years
- Labor
- 1 year field labor (3 years when sold by a Hayward Rewards dealer)
Hayward's 2026 Expert Line residential terms cover in-ground products at 3 years parts and 1 year field labor as standard, extended to 3 years field labor when the heater is sold by a Hayward Rewards dealer (the program formerly branded Totally Hayward). There is no separate longer heat-exchanger term — the cupro-nickel exchanger is covered under the parts warranty as original equipment, while a heat exchanger bought later as a replacement part carries 1 year parts only with no labor. Heating elements and o-rings are treated as normal wear items. Hayward states its limited warranties apply only to product bought from Hayward or a Hayward authorized seller, and the W3-prefixed version of this heater is an Open Line SKU carrying 1 year parts only with no labor coverage. Professional installation and authorized-channel requirements may apply. The commercial ASME variant has its own warranty document, which we have not verified.
Why the heat exchanger matters
The heat exchanger is the part of a pool heater that actually moves heat into the water, and what it is made of decides how long the heater survives Florida water chemistry. Here is what the four materials mean in practice.
- Copper
- The traditional material and the cheapest to build. It transfers heat well and is fine on a well-balanced chlorine pool, but it is the least forgiving of low pH, high chlorine and salt. On the Gulf Coast it is usually the first component to fail.
- Cupro-nickelThis heater
- Copper alloyed with nickel. It gives up a little heat transfer in exchange for much better resistance to unbalanced water chemistry and salt. On gas heaters this is the upgrade worth having in Florida, and some manufacturers now ship it as standard.
- NiTek (nickel alloy)
- A nickel-alloy exchanger used on some gas heaters as a corrosion-resistant alternative to copper. Positioned between cupro-nickel and titanium in both durability and price.
- Titanium
- Effectively immune to pool water chemistry, including salt. It is the standard on quality pool heat pumps and the reason a heat pump can sit on a salt pool for years without exchanger trouble. It is expensive, which is why you rarely see it on gas heaters.
Whatever the material, plumbing order matters just as much: a chlorinator or salt cell belongs downstream of the heater, never upstream.
How we scored it
- Warranty is 3 years parts and 1 year field labor as standard, against 2 years parts and labor on Pentair's MasterTemp and 1 year parts with no labor on Jandy's JXi, and up to 3 years of field labor is available through a Hayward Rewards dealer. Not a 5, because both the labor term and Open Line eligibility depend entirely on where you buy it.
- Durability scores high because cupro-nickel is standard across the line rather than a paid upgrade. On the Gulf Coast that is the most useful thing about this heater.
- 84% thermal efficiency is the top figure in Hayward's own published table for the Universal H-Series, matched only by the 400,000 BTU model.
- Serviceability is the standout: front-panel-only access, universal plumbing unions, a published consumer troubleshooting guide with the full diagnostic code list, and parts stocked widely across Florida.
- Controls lose a point because app control on this SKU means adding a Hayward Omni system — the embedded smart control lives on the HS250FDN instead.
- Value is a 5. You get the corrosion-resistant exchanger, the efficiency of the 400K model and the same warranty structure at the mid-range price tier for its category.
Real Modern Pool Heating installations
Installed locally, researched for everyone
Affordable Solar & Pool Heating, LLC installs and services pool heating in Sarasota, Manatee, Charlotte & Pinellas County, Florida. If you are outside that area this page is still yours to use — take the questions on it to your local contractor. Pool heater installation in Sarasota.
Other heaters worth putting beside it
Same job, different tradeoffs. Every one of these has its own verified spec page.
Pentair · MasterTemp
Pentair MasterTemp 250 NG Gas Pool Heater
Model MasterTemp 250 NG
- BTU input
- 250,000 BTU/hr
- Thermal efficiency
- 84%
- Heat exchanger
- Copper
- Warranty
- 2-Year Parts & Labor
- Wi-Fi / automation
- Automation Compatible
An average-sized Florida pool with no spa, or a pool where gas is the backup to solar or a heat pump rather than the everyday heat source.
Jandy · JXi
Jandy JXi260N Gas Pool & Spa Heater
Model JXI260N
- BTU input
- 260,000 BTU/hr
- Thermal efficiency
- 84%
- Heat exchanger
- Copper
- Warranty
- 1-Year Parts
- Wi-Fi / automation
- App Control via AutomationAutomation Compatible
An average-size Florida pool, or a pool with a small attached spa, on a pad where there is no room for a 400,000 BTU cabinet and no appetite for a 1-inch gas line.
Raypak · AVIA
Raypak AVIA 264A Gas Pool & Spa Heater
Model P-R264A-EN-C
- BTU input
- 264,000 BTU/hr
- Thermal efficiency
- 84%
- Heat exchanger
- Copper
- Warranty
- 3-Year Parts & Labor
- Wi-Fi / automation
- Wi-Fi Built InAutomation Compatible (Relay)
An average-size Florida pool where the owner wants three years of parts and labor cover, plus app control, without buying into an automation system.
H250FDN questions
What size pool is a 250,000 BTU heater right for?
It is the size most residential pools actually want. Hayward's own sizing chart puts the H250 at roughly 750 square feet of pool surface, based on a 30°F temperature rise, 3.5 mph average wind and an elevation up to 2,000 feet. Surface area, whether the pool is screened and how fast you want it to heat matter more than gallons, so we size it against the pool before quoting.
Should I buy the 250 or step up to the 400?
Buy the 400 if you have an attached spa you want hot in under half an hour, a large or very exposed pool, or you plan to heat on demand for weekends. Buy the 250 for a normal residential pool: the efficiency is identical at 84%, the heater is nine inches narrower, and you are not paying to install and feed gas piping for capacity you never use.
Is this heater safe on a salt water pool?
The cupro-nickel heat exchanger is standard on every Universal H-Series model and Hayward describes it as offering excellent salt water and chemical corrosion resistance. As with any heater, the salt cell or chlorinator has to be plumbed downstream of the heater, never upstream — sanitizer pushed back into the exchanger is the fastest way to void the warranty.
Does it work with pool automation?
Yes. Hayward states the heater can be run through any of its Omni control systems, and the cabinet has junction boxes on both sides plus two-wire and three-wire remote terminals to make that wiring straightforward. If you want smart control embedded in the heater itself, that is the HS250FDN with OmniX rather than this SKU.
What does the warranty actually cover?
Hayward's 2026 Expert Line residential terms give 3 years parts and 1 year field labor, with 3 years field labor when the heater is sold by a Hayward Rewards dealer. There is no separate longer heat-exchanger term. The W3-prefixed version sold online is an Open Line SKU with 1 year parts only and no labor coverage, which is worth knowing before you compare prices.
Do you install this heater in Sarasota?
Yes. We install and service Hayward gas heaters throughout Sarasota, Manatee, Charlotte & Pinellas County, Florida. This comparison page is written for pool owners anywhere; the installation offer is local.
Is the H250FDN right for your pool?
We install and service pool heating in Sarasota, Manatee, Charlotte & Pinellas County, Florida. If you are outside that area, the comparison above is still yours to use — ask your local contractor the same questions.
Licensed & insured · Florida Certified Pool/Spa Contractor #CPC1460367 · Mon-Sat, 8am-6pm
Last verified September 17, 2026
Specifications and warranty terms are taken from the manufacturer documents below. Manufacturers revise these without notice, so confirm the current terms before you buy. If you spot something out of date, email us and we will fix it.
Sources
- Hayward — H250FDN product page
- Hayward — Universal H-Series brochure (spec table, thermal efficiency, exchanger)
- Hayward — Universal H-Series Quick Reference Guide (flow, gas pressure, power selection, diagnostic codes)
- Hayward — 2026 Expert Line residential warranty terms
- Hayward — warranty resource page (Expert Line vs Open Line, Hayward Rewards)
Ratings on this site are the editorial opinion of Affordable Solar & Pool Heating, LLC, trading as Modern Pool Heating. How we rate heaters. Corrections: modernpoolheating@icloud.com.
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Mon-Sat, 8am-6pm · Licensed & insured · Florida Certified Pool/Spa Contractor CPC1460367