Which heater is better for a large in-ground pool?

The Raypak 406A. At 399,000 BTU it heats a large pool far faster than the 125,000 BTU Pentair, which Pentair rates for pools up to about 15,000 gallons.

Is the Raypak worth about $2,690 more than the Pentair?

Only if you have a big pool and natural gas. The price gap buys roughly three times the heat output. For a small pool or spa, the Pentair does the job for less.

Can I use the Pentair with natural gas?

The 461061 is the propane model. Pentair sells natural gas versions of the MasterTemp under different part numbers, so match the fuel type to your supply before ordering.

Both use copper heat exchangers and similar 82% efficiency. Longevity depends more on water chemistry, flow rate and correct venting than on the brand.

Do both work with automation systems?

The Pentair connects to IntelliCenter, EasyTouch and IntelliTouch. The Raypak uses its own digital control and is not listed as Pentair-automation compatible.

Which is cheaper to run?

Efficiency is the same at 82%, so cost per BTU of heat depends on fuel price. Natural gas usually costs less per BTU than propane, which favors the Raypak where gas service exists.

Raypak 406A Pool Heater vs Pentair MasterTemp 125K BTU Pool Heater

These are not the same class of heater. The Raypak 406A is a 399,000 BTU natural gas unit for large in-ground pools; the Pentair MasterTemp 461061 is a 125,000 BTU propane heater for pools up to about 15,000 gallons, spas and above-ground pools. The Raypak costs $4,426.00 at The Home Depot as of November 7, 2026, and the Pentair costs $1,736.12 at Pool Supply Harbor as of November 7, 2026. Buy the Raypak for a big pool that needs fast heat; buy the Pentair for a small pool or spa, or if you have propane.

Today the Pentair MasterTemp 125K BTU Pool Heater costs $2,689.88 less at its best price.

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