I'm looking for recommended sizing for an indoor pool. Everything I find is assuming outdoor. It's 18x36 indoor with auto cover. Average depth is 4.5 ft. Getting a Hayward H-series natural gas. Even the Hayward people sent me outdoor recommendation. Any suggestions appreciated.
Indoor pool heater
- Thread starter Oldbowl
- Start date
- Jul 21, 2013
- 65,336
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Welcome to TFP.
Indoor or outdoor pool really does not matter. It is all about BTU's.
How many gallons/pounds of water do you want to raise how many degrees in how many minutes?
A higher BTU heater will raise the temperature of the pool quicker.
A 400K BTU heater will heat the pool in half the time of a 200K heater and both will use about the same amount of gas to do it. So there is no efficiency difference. Just a difference in the initial acquisition cost of the larger BTU heater.
Indoor or outdoor pool really does not matter. It is all about BTU's.
How many gallons/pounds of water do you want to raise how many degrees in how many minutes?
A higher BTU heater will raise the temperature of the pool quicker.
A 400K BTU heater will heat the pool in half the time of a 200K heater and both will use about the same amount of gas to do it. So there is no efficiency difference. Just a difference in the initial acquisition cost of the larger BTU heater.
A Hayward H250 will take nearly twice as long to get the water to temperature as an H400, but the cost is only about $6-700 less, not half. As ajw22 says, for the extra money you are buying convenience (speed). May not be as large an issue on an indoor pool, but should be considered.
Also before you consider the largest heater be sure the gas meter and gas line can supply it.
- Jun 7, 2017
- 9,975
- Pool Size
- 29000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Jandy Aquapure 1400
Most gas heaters can be vented with a pipe to a safe location as well. Just ensure the one you select can.