---
product_id: 147296513
title: "Hayward W3H400FDN Universal H-Series 400,000 BTU Natural Gas Pool and Spa Heater for In-Ground Pools and Spas"
brand: "hayward"
price: "฿541121"
currency: THB
in_stock: true
reviews_count: 7
url: https://www.desertcart.co.th/products/147296513-hayward-w3h400fdn-universal-h-series-400-000-btu-natural-gas
store_origin: TH
region: Thailand
---

# Low NOx Emissions Cupro Nickel Heat Exchanger 400,000 BTU Power Hayward W3H400FDN Universal H-Series 400,000 BTU Natural Gas Pool and Spa Heater for In-Ground Pools and Spas

**Brand:** hayward
**Price:** ฿541121
**Availability:** ✅ In Stock

## Summary

> 🌊 Dive into Comfort with Hayward's Premium Heating!

## Quick Answers

- **What is this?** Hayward W3H400FDN Universal H-Series 400,000 BTU Natural Gas Pool and Spa Heater for In-Ground Pools and Spas by hayward
- **How much does it cost?** ฿541121 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.co.th](https://www.desertcart.co.th/products/147296513-hayward-w3h400fdn-universal-h-series-400-000-btu-natural-gas)

## Best For

- hayward enthusiasts

## Why This Product

- Trusted hayward brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **User-Friendly Operation:** Easily manage your heater with front-panel access and an intuitive control pad.
- • **Eco-Friendly Performance:** Meet air quality standards with low NOx emissions, making your pool experience greener.
- • **Corrosion-Resistant Design:** Enjoy peace of mind with a durable cupro nickel heat exchanger that withstands harsh water conditions.
- • **Unmatched Heating Efficiency:** Experience rapid heating with 400,000 BTUs, perfect for any in-ground pool or spa.
- • **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

Hayward W3H400FDN Universal H-Series 400,000 BTU Natural Gas Pool and Spa Heater for In-Ground Pools and Spas

## Features

- The Hayward Universal H-Series 400,000 BTU Natural Gas Heater delivers premium heating performance for years of reliable, long-lasting comfort
- A durable cupro nickel heat exchanger offers exceptional protection against corrosion and premature failure caused by unbalanced water chemistry
- Industry-leading hydraulic design reduces circulation pump run time to provide major energy savings
- Front-panel-only access and intuitive control pad provide easy operation, service and maintenance
- Low NOx emissions meet air quality standards in all low-NOx areas, ensuring low environmental impact

## Images

![Hayward W3H400FDN Universal H-Series 400,000 BTU Natural Gas Pool and Spa Heater for In-Ground Pools and Spas - Image 1](https://m.media-amazon.com/images/I/61HANADWcVL.jpg)

## Available Options

This product comes in different **Size** options.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Nice heater for the money
*by W***R on September 16, 2022*

We recently installed this heater to go with our Core 35 which is $1,400.00 itself to convert to a pool salt system. Usually our pool is cloudy but since going to salt it’s cleared up considerably. We decided to install a heater after talking about doing so for years now as the pool is almost always cloudy during the summer and Generally we can only swim May - September due to the water getting to chili in October- April. We are hoping with this heater to extend our swimming season to 11 months out of the year. It took roughly 4 days to install it So it was a little hard to hook up we had to run gas lines literally all over the side of our house and through our attic and underground to get to our heater as you can see from the pictures. We tested it out the first night and overnight it warmed our pool from 65* to 80*F, Def can feel the warm water coming out of the jets. Looking forward to trying this out more in October and November when temperatures really drop down but so far I’m pleased with it. Spent roughly $1,200.00 in labor to get the work done and another $800 in parts, like gas line pipes, fittings plumbing and valves… thankfully lowes was able to cut and put the fittings on our gas lines for us but I would say this is a minimum $4,500.00 project undertaking perhaps a bit more if using a pool company, professional plumber or if you live in a big city. We got the 250,000 btu heater and our pool is roughly 22,500 gallons which maybe overkill but wanted to go to big rather than to small on a nice heater…Just wanted to throw that out there for anyone considering getting one installed. That price includes the cost of the unit. The unit really isn’t loud.Update we have had it a little over a week now and we love it! We are in the pool almost daily now. I generally keep the heater on 78* degrees and when I get off work and home around 530pm I’ll cracked it up to 104* and by 7:30pm it’s over 94*! Talking about nice and relaxing I could literally sit in the pool as if it were a hot tub!Updated after a month we are in October now and still like the heater. Gas bill was about $60 more than it normally is for this time of the year and we generally keep the heater on 82F in the pool. One issue we have had is the heater will show the code LO every now and then and will go into a protection mode and will not work until you backwash and let the pressure out

### ⭐⭐⭐⭐⭐ Great unit
*by A***R on June 14, 2025*

Heats fast. Had it Professionalany installed.

### ⭐ Junk don't buy Out 3,000.00
*by S***F on August 22, 2022*

I am very pleased with this heater. Delivery took a little longer than originally anticipated but the communications were consistent if not necessarily the answers I wanted, I did always get an accurate answer. I would attribute it to the hang ups with LTL Trucking in general. I honestly can not fault the vendor, they seemed to be hobbled by the difficulties from the trucking industry. They always did respond.The installation is for an 15 x 30 that goes from 3 to 8 feet deep, in ground pool in the Midwest. I intentionally Oversized the heater because we don't plan on maintaining the temperature, but will fire up the heater prior to when we plan on using the pool. All of the calculations indicated that 150K BTU was sufficient but with the 250K BTU heater I am able to bring up the temperature 1.5 to 2 degrees per hour. So far this theory seems to be working out for us. If during the week the lows are in the high 60's and the highs are in the high 70's to low 80's on Friday after noon or Saturday early morning we can have the pool a pleasant 85 degrees for Friday after work or Saturday late morning. The old heater was removed a couple of years ago and just replaced. But so far it is tough to tell exactly what it has cost to operate because of the overall increase in utility bills, but to date not awful.The installation manual is complete and easily followed but the processes do require significant plumbing, both Gas and Water, and an electrical connection, which may not be present if you are replacing an older milivolt type heater. Fortunately I have done a lot of this type of work over the years and owned the tools and had the skill to complete the installation over the better part of a Saturday afternoon with a few trips to the hardware store.Our pool guy understandably didn't want to install a heater that he didn't sell. I am sure that if we had wanted to we could have hired an Electrician to hook up the electrical and a plumber for the gas and water and still been $$ ahead.The down side is that the policy of the MFG is that the warranty is only valid if installed by one of their Dealer's installers. We have had no issues so far and will cross that bridge if it comes up.****only lasted one season and now it is rusted inside and junk. We are out 3,000.00 and company will not help us. I should have listed to the other reviews.

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*Product available on Desertcart Thailand*
*Store origin: TH*
*Last updated: 2026-01-22*