Pentair MasterTemp 400 vs. MasterTemp 400HD: Which Heater Should You Buy? (460736 vs 460805)
Shopping for a 400,000 BTU Pentair heater and stuck between the MasterTemp 400 (model 460736) and the MasterTemp 400HD (model 460805)? Here's the short version. They heat the same, they're the same size, and they run on the same natural gas. The one real difference is the metal inside the heat exchanger. That single detail decides which heater you should buy.
We get this question a lot at the counter, so let's walk through it the same way we would with a customer standing in front of us.
What's the actual difference between the 460736 and the 460805?
The MasterTemp 400HD (460805) has a cupro-nickel heat exchanger. The standard MasterTemp 400 (460736) uses a copper exchanger. That's it. Same 400,000 BTU output, same Low NOx burner design, same footprint on your equipment pad.
The heat exchanger is the set of metal tubes your pool water runs through while the burner heats them. It's the part of the heater that takes the most abuse, because it sees hot metal and pool water at the same time, all season long.
Copper transfers heat very well and it's the standard choice for most gas pool heaters. Cupro-nickel is a copper alloy with nickel mixed in, and that nickel makes the tubing much tougher against corrosion and erosion. The HD in 400HD basically stands for heavy duty, and that's a fair description.
Is the standard MasterTemp 400 (460736) good enough for most pools?
Yes. If you have a traditional chlorine pool and you keep your water chemistry in a normal range, the standard MasterTemp 400 is a solid pick and it costs less. Copper exchangers hold up fine when pH, alkalinity, and sanitizer levels stay where they should be.
The 460736 is the top output in the standard MasterTemp line, so it heats a pool or spa quickly. For a spa, that matters a lot. Nobody wants to wait two hours for the hot tub to warm up. A 400,000 BTU unit gets a typical attached spa up to temperature fast.
Who should pay extra for the MasterTemp 400HD (460805)?
Buy the 400HD if you have a salt water pool, if your water chemistry tends to drift, or if you just want the most durable version of this heater. Salt systems make chlorine from salt in the water, and that water is harder on copper over time, especially when pH runs low.
A copper exchanger in an aggressive water environment can corrode from the inside. When that happens you'll see symptoms like a heater leaking water from the front, rusty or green staining, or a heat exchanger that fails years before it should. At that point you're pricing out a replacement exchanger or a whole new heater, and neither is cheap.
The cupro-nickel exchanger in the 460805 is built to shrug off exactly that kind of wear. If you're asking "do I need a cupro-nickel heater for a salt water pool," our honest answer is that it's the safer buy. Not mandatory, but smart.
MasterTemp 400 vs 400HD: what does the price difference look like?
The gap is a few hundred dollars. The standard MasterTemp 400 (460736) runs $3,768 and the MasterTemp 400HD (460805) runs $3,999 in our store. On a purchase this size, that's about a 6 percent difference.
Think of it as insurance for the most failure-prone part of the heater. If a copper exchanger fails early on a salt pool, the repair can cost well over the price gap between these two units. If your pool is a standard chlorine setup with steady chemistry, keep the difference in your pocket and buy the 460736.
Quick decision guide
- Standard chlorine pool, chemistry stays balanced: MasterTemp 400, model 460736.
- Salt water pool: MasterTemp 400HD, model 460805.
- Chemistry drifts, or a service company only checks it once in a while: 400HD.
- Rental property or heavy year-round use: 400HD.
- Tight budget and a well-kept traditional pool: the standard 400 will serve you well.
Bottom line on the 460736 vs 460805
Both heaters put out the same 400,000 BTU and both come from the same proven MasterTemp platform. The 460736 is the right call for most traditional chlorine pools. The 460805 earns its higher price on salt water pools and anywhere water chemistry is a question mark, because the cupro-nickel exchanger is simply harder to kill.
Pentair | 460736 | MasterTemp 400K BTU Natural Gas Pool & Spa Heater, Low NOx
$3,768.00
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Pentair | 460805 | MasterTemp 400HD Natural Gas Pool & Spa Heater, 400K BTU, Cupro-Nickel
$3,999.00
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