Hayward H-Series H400FD
A low NOx, salt tolerant in-ground pool heater for owners who buy online and can live with a short warranty.
Amazon $5,099$5,099
399,900 BTU/h84%1 year
3.5/5
For a large in-ground pool on Jandy automation where a compact, light cabinet matters more than price.
- 399,000 BTU/hHeating input
- 84%Efficiency
- Natural gas or propaneGas type
Check price at Amazon$5,300
Price checked November 9, 2026. As an Amazon Associate we earn from qualifying purchases.
Pros
- Large input heats an in-ground pool or spa fast
- Light 126 lb cabinet for a 400k heater, 38% lighter than rivals by Jandy’s count
- Low NOx with 84% efficiency
- Plugs into Jandy AquaLink automation over RS-485
Cons
- Most expensive heater of its size on Amazon
- Warranty terms for online purchases are not published
- Needs a large gas line: 3/4 in pipe is good for only 5 ft
The Jandy JXi family
Every Jandy JXi model we rank, smallest first. Ratings compare each against its own size.
| Model | Heating input | Rating | Price |
|---|---|---|---|
| Jandy JXi 260 | 260,000 BTU/h | 2.2/5 | $4,493.12 |
| Jandy JXi 400 (this one) | 399,000 BTU/h | 3.5/5 | $5,300 |
How it scores
The rating comes from 4 measured or published factors, each scored 0-100 against fixed reference points for its size. How we rank explains each one.
Specifications
| Model number | JXI400N |
|---|---|
| Heating | |
| Gas input | 399,000 BTU/h |
| Gas type | Natural gas or propane |
| Thermal efficiency | 84% |
| Condensing | No |
| Low NOx | Yes |
| Heat exchanger | Copper |
| Max water flow | 100 GPM |
| Installation and controls | |
| Ignition | Electronic |
| Venting | Both |
| Digital controls | Yes |
| Automation or app | Yes |
| Weight | 126 lb |
Alternatives in this size
Raypak Digital 336A
Good value for in-ground pools outside low NOx areas, provided it comes from an authorized dealer so the warranty holds.
Amazon $3,615$3,615
332,000 BTU/h82%2 years
Raypak AVIA 264A
The best rounded in-ground pool heater here for most owners: efficient, low NOx and app controlled with a longer warranty, if bought from an authorized dealer.
Amazon $3,493$3,493
264,000 BTU/h84%3 years
Compare
Compare the Jandy JXi 400 with any other gas pool heater →
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