--- product_id: 147296513 title: "Pool Heater for Inground Pools Universal H-Series 400,000 BTU (Natural Gas Pool Heater) Pool and Spa Heater W3H400FDN Replacement for H400FDN" price: "$12838.65" currency: USD in_stock: true url: https://www.desertcart.us/products/147296513-pool-heater-for-inground-pools-universal-h-series-400-000 store_origin: US region: United States of America --- # Low NOx Emissions Cupro Nickel Heat Exchanger 400,000 BTU Power Pool Heater for Inground Pools Universal H-Series 400,000 BTU (Natural Gas Pool Heater) Pool and Spa Heater W3H400FDN Replacement for H400FDN **Price:** $12838.65 **Availability:** βœ… In Stock ## Summary > 🌊 Dive into Comfort with Hayward's Premium Heating! ## Quick Answers - **What is this?** Pool Heater for Inground Pools Universal H-Series 400,000 BTU (Natural Gas Pool Heater) Pool and Spa Heater W3H400FDN Replacement for H400FDN - **How much does it cost?** $12838.65 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/147296513-pool-heater-for-inground-pools-universal-h-series-400-000) ## Best For - Customers looking for quality international products ## Why This Product - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - β€’ **User-Friendly Operation:** Easily manage your heater with front-panel access and an intuitive control pad. - β€’ **Eco-Friendly Performance:** Meet air quality standards with low NOx emissions, making your pool experience greener. - β€’ **Corrosion-Resistant Design:** Enjoy peace of mind with a durable cupro nickel heat exchanger that withstands harsh water conditions. - β€’ **Unmatched Heating Efficiency:** Experience rapid heating with 400,000 BTUs, perfect for any in-ground pool or spa. - β€’ **Energy-Saving Hydraulic Design:** Reduce your energy bills with an innovative design that minimizes pump run time. ## Overview The Hayward W3H400FDN Universal H-Series is a high-performance natural gas heater designed for in-ground pools and spas, featuring a powerful 400,000 BTU output, a corrosion-resistant cupro nickel heat exchanger, and an energy-efficient hydraulic design that reduces operational costs while ensuring eco-friendly performance. ## Description The Universal H-Series 400,000 BTU Natural Gas Pool & Spa Heater from Hayward provides reliable, long-lasting comfort for pools and spas with a surface area up to 1,200 ft. Built with a durable cupro nickel heat exchanger, it offers exceptional protection against corrosion and premature failure caused by unbalanced water chemistry, ensuring you get season after season of premium heating performance. The Universal H-Series boasts industry-leading hydraulic performance coupled with lightning-fast speed-to-heat capabilityβ€”so you spend less time waiting, and more time swimming. Its low NOx emissions meet air quality standards in all low-NOx areas, so you can rest easy knowing its environmental impact is low, too. ## Features - EASY TO USE: Intuitive inground pool heater control panel enables easy operation and maintenance. The digital LED display helps maintain pool water temperature while monitoring pool water heater performance with self-diagnostic capabilities - MULTIPLE COVERAGE OPTIONS FOR POOLS AND SPAS: This gas pool heater and pool and spa heater suits in-ground pools and spas up to 1200 sq ft with a natural gas connection; additional models cover 450, 600, or 750 sq ft - ENERGY SAVING AND BUILT TO LAST: Efficiently designed pool heater for inground pools helps deliver consistent hot water for swimming pools, reduce pump run time for energy savings, and protect against corrosion caused by unbalanced water chemistry - SIMPLE INSTALLATION: This 400,000 BTU Hayward natural gas pool heater allows flexible gas and electric connections on the right or left side, with an H-Series built-in 3/4" gas connection for easier fuel line setup - LOW ENVIRONMENTAL IMPACT: Hayward gas pool heaters for inground use are certified for low-NOx emissions and eco-friendly operation, reducing circulation pump run time while delivering a reliable swimming pool heater solution for inground pools ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B07SQ2MDQQ | | Best Sellers Rank | #61,660 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #6 in Swimming Pool Heaters | | Customer Reviews | 4.1 4.1 out of 5 stars (178) | | Item Weight | 195 pounds | | Item model number | W3H400FDN | | Manufacturer | Hayward | | Product Dimensions | 29.5 x 34 x 24 inches | ## Images ![Pool Heater for Inground Pools Universal H-Series 400,000 BTU (Natural Gas Pool Heater) Pool and Spa Heater W3H400FDN Replacement for H400FDN - Image 1](https://m.media-amazon.com/images/I/61HANADWcVL.jpg) ![Pool Heater for Inground Pools Universal H-Series 400,000 BTU (Natural Gas Pool Heater) Pool and Spa Heater W3H400FDN Replacement for H400FDN - Image 2](https://m.media-amazon.com/images/I/51V-EkKOe0L.jpg) ![Pool Heater for Inground Pools Universal H-Series 400,000 BTU (Natural Gas Pool Heater) Pool and Spa Heater W3H400FDN Replacement for H400FDN - Image 3](https://m.media-amazon.com/images/I/61OheYonDVL.jpg) ![Pool Heater for Inground Pools Universal H-Series 400,000 BTU (Natural Gas Pool Heater) Pool and Spa Heater W3H400FDN Replacement for H400FDN - Image 4](https://m.media-amazon.com/images/I/71lM3dAa2fL.jpg) ![Pool Heater for Inground Pools Universal H-Series 400,000 BTU (Natural Gas Pool Heater) Pool and Spa Heater W3H400FDN Replacement for H400FDN - Image 5](https://m.media-amazon.com/images/I/71kU97vnQxL.jpg) ## Available Options This product comes in different **Size** options. ## Frequently Bought Together - Hayward W3H400FDN Universal H-Series 400,000 BTU Natural Gas Pool and Spa Heater for In-Ground Pools and Spas - Hayward SPX3200UNKIT Union Connector Replacement Kit for Select Hayward Pump and Heater - 2 PACK -CMP Hi-Temp Union 2" inch 2MIP x 2" inch PVC Whisperflo & Intelliflo - 2 PACK --- ## Why Shop on Desertcart? - πŸ›’ **Trusted by 1.3+ Million Shoppers** β€” Serving international shoppers since 2016 - 🌍 **Shop Globally** β€” Access 737+ million products across 21 categories - πŸ’° **No Hidden Fees** β€” All customs, duties, and taxes included in the price - πŸ”„ **15-Day Free Returns** β€” Hassle-free returns (30 days for PRO members) - πŸ”’ **Secure Payments** β€” Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** β€” Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.us/products/147296513-pool-heater-for-inground-pools-universal-h-series-400-000](https://www.desertcart.us/products/147296513-pool-heater-for-inground-pools-universal-h-series-400-000) --- *Product available on Desertcart United States of America* *Store origin: US* *Last updated: 2026-05-10*