Best VST Speed for Heater - A Little Help? Year-Round In South West Missouri


New member
Jan 9, 2021
Waynesville MO
I guess I am supposed to introduce myself?

My name is Chuck Williams. I am originally from NJ and I retired from Army after 33 years in Missouri. We had an in-ground fiberglass pool installed in Sep 14. We keep it open year-round. Yes, it is covered when we are not using it (solar cover). We have Pentair Pool Equipment. We have a Pentair Master Temp 250 Heater and we just replaced our Whisperflo W4 single-speed Pump with a Pentair Superflo VST.

What is the optimum pump speed for heating (raising the temp), and for maintaining the temp? Higher or Lower? I have seen many varying opinions.

Since we keep the heater on 24/7, I am trying to figure out the best Pump speed for both efficiency, filtering, and heating. We use a pool robot, so never use any suction vacuum.

The old one ran steady at 3450. The heater will run at low flow rates like say 1400, as it has a switch just in case the flow is too low or stops. Right now it is at 1900 for 2400 hours

I was thinking higher was better for both heating fast and maintaining, but I have seen no definitive answer? I have seen low speed is better for both. I have seen low speed is better for electrical, but not for heating, which still saves more.

Can I get a little help?

Thank you.

Chuck W


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Welcome to the forum!
You have a thread on this question so let's keep the discussion there.
I suggest you read ABC's of Pool Water Chemistry.