Best 400K BTU Pool Heaters
Updated May 2025
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Best 400K BTU Pool Heaters
2025 Buyer's GuideUpdated May 2025
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Hayward W3H400FDN Universal H-Series 400,000 BTU Natural Gas Pool and Spa Heater for In-Ground Pools and Spas
Functionality
Heat level
Ease of installation
Energy efficiency
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Our Top Choice
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Hayward W3H400FDN Universal H-Series 400,000 BTU Natural Gas Pool and Spa Heater for In-Ground Pools and Spas
Functionality
Heat level
Ease of installation
Energy efficiency
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