Search  for anything...
Hayward

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

    • Based on 464 reviews
Condition: New
Checking for product changes
$3,999.00 Why this price?

Buy Now, Pay Later

As low as / mo
  • – Up to 36-month term with PayTomorrow
  • – No impact on credit
  • – Instant approval decision
  • – Secure and straightforward checkout

Ready to go? Add this product to your cart and select a plan during checkout. Payment plans are offered through our trusted finance partners Klarna, PayTomorrow, Apple Pay, and PayPal. No-credit-needed leasing options through Acima may also be available at checkout.

Learn more about financing & leasing here.

Selected Option

Free shipping on this product

Eligible for Return, Refund or Replacement within 30 days of receipt

To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

Availability: In Stock.
Fulfilled by In The Swim Pool Supplies
Arrives Thursday, Apr 25
Order within 17 hours and 24 minutes
Available payment plans shown during checkout

Size: 400,000 BTU (W3H400FDN)


Features

  • BEST FOR: In-ground pools and spas with a surface area up to 1,200 ft. where natural gas is available. Its low environmental impact makes it ideal for pools and spas located where low-NOx emissions are required.
  • PREMIUM PERFORMANCE: The Hayward Universal H-Series 400,000 BTU Natural Gas Heater delivers fast premium heating performance for years of reliable, long-lasting comfort.
  • CORROSION PROTECTION: The Universal H-Series boasts exceptional protection against corrosion and premature failure caused by unbalanced water chemistry.
  • ENERGY SAVINGS: The efficient, industry-leading design reduces circulation pump run time to provide energy savings.
  • EASY-TO-USE: Intuitive front control panel provides easy operation, service and maintenance.

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 capability—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.

Product Dimensions: 39.6 x 32.8 x 30.6 inches


Item Weight: 195 pounds


Manufacturer: Hayward


Item model number: W3H400FDN


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Thursday, Apr 25

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

  • Klarna Financing
  • Klarna Pay in 4
  • PayTomorrow Financing
  • Apple Pay Later
Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

Similar Products

Top Amazon Reviews

    • Nice heater for the money
Size: 250,000 BTU (W3H250FDN)
Review Image by wkmgator wkmgator
Review Image by wkmgator wkmgator
Review Image by wkmgator wkmgator
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 ... show more
Reviewed in the United States on September 16, 2022 by wkmgator wkmgator
    • Excellent heater
Size: 400,000 BTU (W3H400FDN)
Heater works great had a 200,000 Hayward prior to this and a 20,000 gallon inground pool the 200,000 struggled to keep up and eventually stopped working so I decided to go big with the 400 great move because it pretty much slipped right into the same fittings that the 200 had the only thing I had to change was my gas and that was minimal Had it up and running in a couple hours and heated the pool 20° overnight. The shipping was excellent R & L carriers delivered it. It showed up without a mark on it. It was a few days late, so I was mad about that but other than being a few days late I definitely go back to that company again they did a great job shipping it ... show more
Reviewed in the United States on August 20, 2023 by jim
    • Junk don't buy Out 3,000.00
Size: 250,000 BTU (W3H250FDN)
Review Image by SEF SEF
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. ... show more
Reviewed in the United States on August 22, 2022 by SEF SEF
    • Best Heater I have Owned
Size: 400,000 BTU (W3H400FDN)
So I purchased nearly identical model 17 years ago. Self installed except for need of larger supply line for gas input that required a licensed plumber. While I did have a couple failures related to the odd geckos crawling up behind a circuit board with 220 voltage (part easily obtained from Amazon and replaced myself) and shorting out. The heater performed wonderfully! Fast forward to this spring and it was not working after winter months. No input from control board. Tested things I was sure of to no avail. BUT then realized this was 17 years old! I purchased this newer version and it arrived. Unwired and unplumbed from old and connections identical to new. Rewired and replumbed in about 45 minutes and it was up and running 100%. Highly Recommend Hayward products. I also use there pool pumps and sand filters among other odds and ends. Always satisfied! ... show more
Reviewed in the United States on September 1, 2023 by Douglas Pilcher

Can't find a product?

Find it on Amazon first, then paste the link below.