When do you turn on your heater?

Mattikuss · Apr 5, 2025

I’m in Minnesota and the pool guys open it on Monday (my pool is under warranty and I am required to pay the pool builder to open and close while under warranty - 2 years). My plan is to not heat the pool until it’s more consistently warmer outside, what would your target temp be?

Also, am I crazy to heat it for a freak warm day, say, next Friday when it is high 70s?

Matt

ajw22 · Apr 5, 2025

What is your water temperature?

Your heater will heat your pool about 1 degree per hour.

Beware of causing corrosive condensation…

Heater Condensation - Further Reading

www.troublefreepool.com

What is your cost per therm of NG?

What is a swimming temperature for you?

Newdude · Apr 5, 2025

Mattikuss said:
Also, am I crazy to heat it for a freak warm day, say, next Friday when it is high 70s?

Is the first swim of the season worth it to you ? I found we were always excited about it in the early season, and passed on it in the fall and went for a bike ride in hoodies instead.

This is where a gas heater excels. If Saturday is looking nice and everybody is into it, fire it up on Friday and enjoy the pool day. If you have 9 other things going on Saturday, don't fire up the pool. Repeat as necessary until you want it consistently warm.

EmilyOTR · Apr 5, 2025

we open in Michigan on April 23. we probably won't heat it until May and there's a warm day in the forecast. We would heat it for a random warm day, yes. my profile picture is our yearly jump in. we don't go in the pool til we have jumped in as a family! Usually that is the first warmish day. I say warmish because we've done this on very cool days as we just want to get it done so if the kids want to swim they can. I know we are ridiculous but we like our tradition.

clambert1273 · Apr 5, 2025

Lol High 70's is my winter

sande005 · Apr 5, 2025

Another Minnesotan here. You are definitely pushing it. The ice just came off the lakes not too long ago in the Metro area! There are still chances for snow in late April. (My Bday is then, and it snows a bit on the majority of them!)
Me? I tend not to fire up the heater until near Memorial Day. It will take about an hour to raise the pool 1 degree. So if going from 60 to 80, that is a long time continuously burning gas. A bubble wrap cover will help stem some overnight heat loss, when the air temps drop to below 50 - but it won't be a order of magnitude cost saver. It is truly a wonder how fast a pool will give up that expensive heat when the weather chills. All I can guarantee is you definately will loose when you get the Xcel energy report comparing you to your most/least efficient neighbors. You will be the one everyone else is better than!

sande005 · Apr 6, 2025

I roughed it out based on that 1 degree per hour, and a 20 degree rise - in the Minneapolis area the cost would be $3.40/hr or $68 to get to temp. that first day. The thermodynamics defeat me as to how to guess the ongoing cost to maintain. All I know is after the very first summer with the pool, almost 35 years ago, I avoid use of the heat unless there is a overwhelming demand (high school graduation party, the daughter with the Oct birthday celebrating her 16th, etc).

It is mostly used in the main part of summer, when there may have been a cool period, and I want to get the temp back up to swimming in anticipation of coming warmer forecasts.