Proper sizing of a pool heat pump can be very simple.  

Every application is different depending on desired temperatures, circulation times, shading etc.  If you would like a recommendation based on your specific application, please contact us with the specifications at sales@gulfstreamheatpump.com

As a rule of thumb, here are suggestions based on pool sizes under standard conditions:

HE/HI110 –  (Up to 15,000 gallons or 450 square feet)

HE/HI125 –  (Up to 23,000 gallons or 650 square feet)

HE/HI150 –  (Up to 27,000 gallons or 800 square feet)

Use of a pool cover will reduce heat losses by 50%.

When using heat pumps to heat a spa – we always suggest to go up a size since you cannot oversize a pool heat pump.