Pentair MasterTemp 400
A strong pick for in-ground pools already on Pentair automation, though online buyers get only a short warranty.
Amazon $4,079$4,079
The Pentair MasterTemp 400 is the better gas pool heater overall, rated 3.9 to 3.5. The Pentair MasterTemp 400 leads on heating input, efficiency and value. The Raypak Digital 336A wins on warranty. The Raypak Digital 336A costs $464 less ($3,615 vs $4,079).
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 Pentair MasterTemp 400 for heating input (400,000 BTU/h vs 332,000 BTU/h), efficiency (84% thermal efficiency vs 82% thermal efficiency) and value ($10.20 per 1,000 BTU/h ($4,079, 400,000 BTU/h) vs $10.89 per 1,000 BTU/h ($3,615, 332,000 BTU/h)).
- Choose the Raypak Digital 336A for warranty (2-year warranty vs 1-year warranty).
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 | Pentair MasterTemp 400 | Raypak Digital 336A |
|---|---|---|
| Overall rating | 3.9/5 | 3.5/5 |
| Value 35% | 84 $10.20 per 1,000 BTU/h ($4,079, 400,000 BTU/h) | 76 $10.89 per 1,000 BTU/h ($3,615, 332,000 BTU/h) |
| Heating input 25% | 100 400,000 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
| Pentair MasterTemp 400 | Raypak Digital 336A | |
|---|---|---|
| Heating | ||
| Gas input | 400,000 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 | Copper | Copper |
| Max water flow | 120 GPM | 100 GPM |
| Installation and controls | ||
| Ignition | Electronic | Electronic |
| Venting | Both | Both |
| Digital controls | Yes | Yes |
| Automation or app | Yes | Yes |
| Weight | 136 lb | - |
| Warranty | 1 year | 2 years |