{"product_id":"hayward-h135-pool-heater-natural-gas-135k-btu","title":"Hayward H135 Pool Heater Natural Gas 135K BTU","description":"\u003c!-- more --\u003e\n\u003cp\u003eThe W3H135FDN is a natural gas pool heater built for above-ground pools and spas on Hayward's H-Series platform. It delivers 135,000 BTU\/hr of heating output, operates in low ambient temperatures down to 40 degrees F, and uses a cupro nickel heat exchanger built to handle demanding pool water conditions. At 100 lb and 21.4\" wide, it is the most compact model in the H-Series natural gas lineup - easy to position and straightforward to service.\u003c\/p\u003e\n\n\u003ch2\u003eW3H135FDN H-Series Above-Ground Natural Gas Pool Heater - Specs and Features\u003c\/h2\u003e\n\u003cp\u003eThe W3H135FDN runs on 120V single-phase, 60 Hz power and draws 5.5 circuit amps with a 15-amp maximum breaker. This model is 120V only - it does not have the field-conversion option found on the larger in-ground Universal H-Series models. It supports water flow between 20 and 125 GPM and uses an induced draft combustion design. The cabinet measures 22.6\" H x 21.4\" W x 30.3\" L and weighs 100 lb.\u003c\/p\u003e\n\n\u003ch3\u003eW3H135FDN Installation and Clearance Requirements\u003c\/h3\u003e\n\u003cp\u003eThe W3H135FDN requires 6 inches of rear clearance and 12 inches on each side. The induced draft system controls combustion airflow internally, so no high-wind stack is required for outdoor installations. Before setting the unit, confirm your natural gas meter capacity and supply line sizing are sufficient - undersized piping or a low-capacity meter will cause startup and performance problems regardless of how well everything else is installed. This model is designed for outdoor above-ground pool installations; confirm local code requirements for any semi-enclosed equipment areas.\u003c\/p\u003e\n\n\u003ch2\u003eH-Series Combustion System and Pool Sizing\u003c\/h2\u003e\n\u003cp\u003eThe W3H135FDN uses an induced draft design that moves combustion air through the chamber at a controlled rate, keeping heat output consistent across varying outdoor conditions. Hayward's hydraulic design maintains uniform water velocity across all heat exchanger tubes, which produces faster heat-up times and reduced pump run time. At 135,000 BTU\/hr, this unit is well matched for above-ground pools in the 5,000 to 15,000 gallon range and spas where fast warm-up is the priority. It can handle up to around 25,000 gallons in warm climates where heat loss is minimal, but the sweet spot is smaller water volumes where it heats quickly and efficiently. Natural gas also runs cheaper than propane in most markets, giving this model a lower operating cost than the \u003ca href=\"https:\/\/nonstopswim.com\/products\/hayward-h135-pool-heater-propane-135k-btu\" title=\"Hayward W3H135FDP Propane Pool Heater 135K BTU\"\u003eW3H135FDP\u003c\/a\u003e over time.\u003c\/p\u003e\n\n\u003ch3\u003eCupro Nickel Heat Exchanger and Water Chemistry Durability\u003c\/h3\u003e\n\u003cp\u003eThe W3H135FDN uses a cupro nickel heat exchanger with Hayward's managed water flow design, which keeps the same water velocity through all tubes for consistent heat transfer. Cupro nickel handles salt water and aggressive pool chemistry better than standard copper alternatives - a meaningful spec even on above-ground pools running salt systems or higher sanitizer levels. Heat exchanger corrosion is one of the more common long-term failure points on gas heaters, so the material choice matters regardless of pool type.\u003c\/p\u003e\n\n\u003ch3\u003eW3H135FDN vs. In-Ground H-Series Models - Key Differences\u003c\/h3\u003e\n\u003cp\u003eThe W3H135FDN is purpose-built for above-ground pools and differs from the in-ground Universal H-Series line in a few important ways. It runs on 120V only rather than the field-convertible 120\/240V setup on models like the \u003ca href=\"https:\/\/nonstopswim.com\/products\/hayward-h150-pool-heater-natural-gas-150k-btu\" title=\"Hayward W3H150FDN Natural Gas Pool Heater 150K BTU\"\u003eW3H150FDN\u003c\/a\u003e. It uses an induced draft rather than forced draft combustion. And at 100 lb, it is significantly lighter than the next step up in the natural gas lineup. If your pool is in-ground or larger than 25,000 gallons, the \u003ca href=\"https:\/\/nonstopswim.com\/products\/hayward-h150-pool-heater-natural-gas-150k-btu\" title=\"Hayward W3H150FDN Natural Gas Pool Heater 150K BTU\"\u003eW3H150FDN\u003c\/a\u003e or \u003ca href=\"https:\/\/nonstopswim.com\/products\/hayward-h200-pool-heater-natural-gas-200k-btu\" title=\"Hayward W3H200FDN Natural Gas Pool Heater 200K BTU\"\u003eW3H200FDN\u003c\/a\u003e are the right direction.\u003c\/p\u003e\n\n\u003ctable\u003e\n  \u003ccaption\u003e\u003cstrong\u003eFull Specifications - Hayward W3H135FDN Natural Gas Above-Ground Pool Heater\u003c\/strong\u003e\u003c\/caption\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eHayward\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eModel \/ SKU\u003c\/td\u003e\n\u003ctd\u003eW3H135FDN\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSeries\u003c\/td\u003e\n\u003ctd\u003eH-Series\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eFuel Type\u003c\/td\u003e\n\u003ctd\u003eNatural Gas\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eAbove-Ground Pools and Spas\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003ePool Type\u003c\/td\u003e\n\u003ctd\u003eAbove Ground\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eHeating Capacity\u003c\/td\u003e\n\u003ctd\u003e135,000 BTU\/hr\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eKilowatts\u003c\/td\u003e\n\u003ctd\u003e40 kW\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eHeat Exchanger\u003c\/td\u003e\n\u003ctd\u003eCupro nickel\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eLow NOx\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eCooling Capability\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eLow Ambient Operation\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eMinimum Operating Temperature\u003c\/td\u003e\n\u003ctd\u003e40 degrees F\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eVoltage\u003c\/td\u003e\n\u003ctd\u003e120V\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003ePhase\u003c\/td\u003e\n\u003ctd\u003eSingle\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eFrequency\u003c\/td\u003e\n\u003ctd\u003e60 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eCircuit Amps\u003c\/td\u003e\n\u003ctd\u003e5.5\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eMaximum Breaker Size\u003c\/td\u003e\n\u003ctd\u003e15 Amps\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eWater Flow Rate\u003c\/td\u003e\n\u003ctd\u003e20 to 125 GPM\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eRear Clearance\u003c\/td\u003e\n\u003ctd\u003e6\"\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSide Clearance\u003c\/td\u003e\n\u003ctd\u003e12\"\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eProduct Dimensions (H x W x L)\u003c\/td\u003e\n\u003ctd\u003e22.6\" x 21.4\" x 30.3\"\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eProduct Weight\u003c\/td\u003e\n\u003ctd\u003e100 lb\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eShipping Dimensions\u003c\/td\u003e\n\u003ctd\u003e27.3\" x 25\" x 37\"\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eShipping Weight\u003c\/td\u003e\n\u003ctd\u003e117.5 lb\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eActive Defrost\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eBoost Mode\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSilent Mode\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eChannel\u003c\/td\u003e\n\u003ctd\u003eOpen Line\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eIs this heater for above-ground pools or in-ground pools?\u003c\/summary\u003e\n  \u003cp\u003eAbove-ground pools and spas. The W3H135FDN is specifically designed for above-ground applications. If you have an in-ground pool, the \u003ca href=\"https:\/\/nonstopswim.com\/products\/hayward-h150-pool-heater-natural-gas-150k-btu\" title=\"Hayward W3H150FDN Natural Gas Pool Heater 150K BTU\"\u003eW3H150FDN\u003c\/a\u003e is the starting point in the Universal H-Series in-ground lineup.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eWhat size pool can a 135,000 BTU heater handle?\u003c\/summary\u003e\n  \u003cp\u003eAt 135,000 BTU\/hr, this unit is well matched for above-ground pools in the 5,000 to 15,000 gallon range and spas where fast heat-up is the priority. It can handle up to around 25,000 gallons in warm climates where heat loss is low. For larger volumes, step up to the \u003ca href=\"https:\/\/nonstopswim.com\/products\/hayward-h150-pool-heater-natural-gas-150k-btu\" title=\"Hayward W3H150FDN Natural Gas Pool Heater 150K BTU\"\u003eW3H150FDN\u003c\/a\u003e or \u003ca href=\"https:\/\/nonstopswim.com\/products\/hayward-h200-pool-heater-natural-gas-200k-btu\" title=\"Hayward W3H200FDN Natural Gas Pool Heater 200K BTU\"\u003eW3H200FDN\u003c\/a\u003e.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eWhat fuel and electrical service does this model require?\u003c\/summary\u003e\n  \u003cp\u003eNatural gas only, with 120V single-phase, 60 Hz power and a 15-amp maximum breaker drawing 5.5 circuit amps. This model runs on 120V only - it does not have the 120\/240V field-conversion option found on the larger in-ground H-Series models.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eIs this the natural gas or propane version?\u003c\/summary\u003e\n  \u003cp\u003eNatural gas. If your site runs propane, you need the \u003ca href=\"https:\/\/nonstopswim.com\/products\/hayward-h135-pool-heater-propane-135k-btu\" title=\"Hayward W3H135FDP Propane Pool Heater 135K BTU\"\u003eW3H135FDP\u003c\/a\u003e instead. The two are not interchangeable without a conversion, which should be done by a licensed technician.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eWhy does the cupro nickel heat exchanger matter?\u003c\/summary\u003e\n  \u003cp\u003eCupro nickel handles salt water and aggressive pool chemistry better than standard copper alternatives. Even on above-ground pools, if you're running a salt system or elevated sanitizer levels, the material choice has real long-term impact on heat exchanger durability.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eDoes this heater need a special vent stack or chimney?\u003c\/summary\u003e\n  \u003cp\u003eNo. The induced draft system controls combustion airflow internally, so performance is not dependent on wind or stack height. Always follow the installation manual and local code for final venting setup, especially in any semi-enclosed spaces.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eDoes the W3H135FDN meet low NOx requirements?\u003c\/summary\u003e\n  \u003cp\u003eYes. It meets Low NOx clean air standards including SCAQMD Rule 1146.2, which applies in parts of Southern California and some other air quality districts. If your municipality requires low NOx compliance for pool heaters, this model qualifies.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eW3H135FDN Warranty, Manuals, and Product Literature\u003c\/h2\u003e\n\u003cp\u003eThe W3H135FDN includes a \u003cstrong\u003e1-year parts warranty\u003c\/strong\u003e with no labor coverage. Review the installation manual before any work begins to confirm gas supply, venting, and clearance requirements are met at the site.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0683\/3592\/7513\/files\/Hayward-H135-Manual.pdf?v=1728578388\" target=\"_blank\" rel=\"noopener noreferrer\" title=\"Hayward W3H135FDN H-Series 135K BTU Natural Gas Pool Heater Installation and Operation Manual\"\u003eHayward H-Series 135K BTU Natural Gas Pool Heater Installation and Operation Manual\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0683\/3592\/7513\/files\/Hayward-H135-Brochure.pdf?v=1728578388\" target=\"_blank\" rel=\"noopener noreferrer\" title=\"Hayward W3H135FDN H-Series 135K BTU Natural Gas Pool Heater Product Brochure\"\u003eHayward H-Series 135K BTU Natural Gas Pool Heater Product Brochure\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Hayward","offers":[{"title":"Default Title","offer_id":48264448573657,"sku":"W3H135FDN","price":2399.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0683\/3592\/7513\/files\/Hayward-H135-Pool-Heater-by-pool.jpg?v=1774503723","url":"https:\/\/nonstopswim.com\/products\/hayward-h135-pool-heater-natural-gas-135k-btu","provider":"Nonstop Swim","version":"1.0","type":"link"}