Recommended Heat Pump Size for 20x40 inground pool


Well-known member
Nov 9, 2015
Lawrence, KS
Looking to add a heat pump to a 20x40 (30,000 gallons) inground pool. Looking to extend season from May thru Sept which has average temps in May/Sept around 60 degrees. Would like to keep water around 85 degrees. I'm assuming I need a heat pump with about 140,000 BTU but wanted to get other thoughts or personal experience on size and brand.


TFP Expert
In The Industry
Jul 6, 2011
The largest you can afford. You will be happy you did. Just keep in mind that outside air temps 60 or below makes these units very inefficient and will not produce much heat. Also invest in a solar blanket for the pool to help reduce your heat losses when you are using the heat pump.


TFP Expert
Platinum Supporter
LifeTime Supporter
Moderator Emeritus
Aug 10, 2012
FL panhandle
+1 to that. Your pool is BIG and your heat pump needs to be BIG! And a solar cover overnight will help a lot..


Active member
Sep 7, 2012
Based on 4 years experience with heat pump I would go with a gas heater. My heat pump does not work well at 60 degrees and takes all day to
Heat the pool a few degrees