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
The Hayward H-Series H400FD and the Raypak Digital 336A are evenly matched, rated 3.5 and 3.5. The Hayward H-Series H400FD leads on heating input and efficiency. The Raypak Digital 336A wins on warranty and value. The Raypak Digital 336A costs $1,484 less ($3,615 vs $5,099).
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
Prices were last checked October 31, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Hayward H-Series H400FD for heating input (399,900 BTU/h vs 332,000 BTU/h) and efficiency (84% thermal efficiency vs 82% thermal efficiency).
- Choose the Raypak Digital 336A for warranty (2-year warranty vs 1-year warranty) and value ($10.89 per 1,000 BTU/h ($3,615, 332,000 BTU/h) vs $12.75 per 1,000 BTU/h ($5,099, 399,900 BTU/h)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 250,000 BTU and up gas pool heater; a clear win is highlighted. How we rank explains each one.
| Factor weight | Hayward H-Series H400FD | Raypak Digital 336A |
|---|---|---|
| Overall rating | 3.5/5 | 3.5/5 |
| Value 35% | 56 $12.75 per 1,000 BTU/h ($5,099, 399,900 BTU/h) | 76 $10.89 per 1,000 BTU/h ($3,615, 332,000 BTU/h) |
| Heating input 25% | 100 399,900 BTU/h | 55 332,000 BTU/h |
| Efficiency 20% | 67 84% thermal efficiency | 33 82% thermal efficiency |
| Warranty 20% | 0 1-year warranty | 50 2-year warranty |
Specifications
| Hayward H-Series H400FD | Raypak Digital 336A | |
|---|---|---|
| Heating | ||
| Gas input | 399,900 BTU/h | 332,000 BTU/h |
| Gas type | Natural gas or propane | Natural gas or propane |
| Thermal efficiency | 84% | 82% |
| Condensing | No | No |
| Low NOx | Yes | No |
| Heat exchanger | Cupro-nickel | Copper |
| Max water flow | 125 GPM | 100 GPM |
| Installation and controls | ||
| Ignition | Electronic | Electronic |
| Venting | Both | Both |
| Digital controls | Yes | Yes |
| Automation or app | Yes | Yes |
| Weight | 195 lb | - |
| Warranty | 1 year | 2 years |