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 2.8. The Pentair MasterTemp 400 leads on heating input and value. The Pentair MasterTemp 400 costs $20.99 less ($4,079 vs $4,099.99).
Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.
Pentair MasterTemp 300
For a typical in-ground pool on Pentair automation that wants faster heat than a 250 without the gas line a 400 needs.
Amazon $4,099.99$4,099.99
Which should you buy?
- Choose the Pentair MasterTemp 400 for heating input (400,000 BTU/h vs 300,000 BTU/h) and value ($10.20 per 1,000 BTU/h ($4,079, 400,000 BTU/h) vs $13.67 per 1,000 BTU/h ($4,099.99, 300,000 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 | Pentair MasterTemp 400 | Pentair MasterTemp 300 |
|---|---|---|
| Overall rating | 3.9/5 | 2.8/5 |
| Value 35% | 84 $10.20 per 1,000 BTU/h ($4,079, 400,000 BTU/h) | 48 $13.67 per 1,000 BTU/h ($4,099.99, 300,000 BTU/h) |
| Heating input 25% | 100 400,000 BTU/h | 33 300,000 BTU/h |
| Efficiency 20% | 67 84% thermal efficiency | 67 84% thermal efficiency |
| Warranty 20% | 0 1-year warranty | 0 1-year warranty |
Specifications
| Pentair MasterTemp 400 | Pentair MasterTemp 300 | |
|---|---|---|
| Heating | ||
| Gas input | 400,000 BTU/h | 300,000 BTU/h |
| Gas type | Natural gas or propane | Natural gas or propane |
| Thermal efficiency | 84% | 84% |
| Condensing | No | No |
| Low NOx | Yes | Yes |
| Heat exchanger | Copper | Copper |
| Max water flow | 120 GPM | 120 GPM |
| Installation and controls | ||
| Ignition | Electronic | Electronic |
| Venting | Both | Both |
| Digital controls | Yes | Yes |
| Automation or app | Yes | Yes |
| Weight | 136 lb | 136 lb |
| Warranty | 1 year | 1 year |