Best way to heat pool – 2-speed pump running on high or low?

Electric heaters, gas heaters, heat pumps,
solar heaters, geothermal heating, solar pool
covers and wood-burning pool heating equipment.
star_bd

Best way to heat pool – 2-speed pump running on high or low?

Postby star_bd » Wed 26 Oct, 2011 17:04

Hi all,

This past summer, we incurred some large gas bills while heating our pool, and I am hoping some folks have some advice related to the most economical way to heat our pool.

We have a gas heater, a 2-speed pump, and a medium-size pool.

To heat the pool, we run the pump on high speed for ~9 hours per day for several consecutive days.

My question is – what’s better and more economical, to heat the pool with the pump on high speed or on low speed?

I see the merit in both situations and am curious if the masses feel one approach is better. I have not tried to heat the pool on the low speed:

Aspects of heating on high speed:
Pro - Water flows faster and circulates better
Negative – a lot more expensive

Aspects/Questions of heating on low speed:
Does the lower speed generate enough circulation to heat the pool?
Would the water be warmer leaving the heater since it exposed longer to the heater?
Would it take longer (or significantly longer) to heat the pool?

Any advice, recommendations, ideas, links, et al are appreciated.

Bill


User avatar
mas985
Swimming Pool Pro
Swimming Pool Pro
Posts: 199
Joined: Tue 08 Sep, 2009 10:40
Location: Pleasanton, CA, USA

Best way to heat pool – 2-speed pump running on high or low?

Postby mas985 » Wed 26 Oct, 2011 18:28

You may not have enough flow rate to operate on low speed but you would need to check that out. The trade off is in electricity (pump) vs gas (heater). You will save about 50% on your electrical energy with low speed. But the lower speed will decrease the efficiency of the heater some but probably not enough to make up for the increase in energy efficiency of the pump. So your gas bill might go up a bit but your electrical bill would go down a lot.

Your other questions:

Does the lower speed generate enough circulation to heat the pool? - It should

Would the water be warmer leaving the heater since it exposed longer to the heater? - Yes in to out temperature rise doubles on low speed which is why the heat loss is higher.

Would it take longer (or significantly longer) to heat the pool? - You would be adding about the same BTUs but more might be lost in the plumbing so overall it might take slightly longer to heat.

This may all be moot if you have a controller and if forces you to use high speed when running the heater.
Mark
Hydraulics 101 ; Pump and Pool Spreadsheets ; Pump Ed 101
18'x36' 20k gallon plaster/gunite pool, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge Filter, Solar Panels, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater
preeti22
Pool Enthusiast
Pool Enthusiast
Posts: 13
Joined: Thu 09 Aug, 2012 02:59

Best way to heat pool – 2-speed pump running on high or low?

Postby preeti22 » Fri 26 Oct, 2012 07:54

solar pool covers is also great option for winter. they are removable and saves lot of energy.

Return to “Solar & Pool Heaters”

Who is online at the Pool Help Forum

Users browsing this forum: No registered users and 1 guest