Understanding Evaporative Loss in Swimming Pools

by Monique Nelson on June 1st, 2012

On occasion, I get customers who are't wholly satisficed with the results they have seen using our EcosavrTM liquid pool cover. As you can imagine I hate to hear these sentiments and I immediately have a burning desire to know exactly WHY? So, I begin asking questions...

I like to start easy:

What were you expecting the results of using EcosavrTM to be?

Unfortunately, not many people know how to respond to this. So I try to help them out...
Well, if you don't heat your pool, EcosavrTM will help you save about 50% of your overnight heat loss. Which means if you were dropping in temperature from 80 degrees to 70 degrees before you started using EcosavrTM, after a few days with the liquid pool cover you should only be dropping to about 75 degrees. In the morning, a higher starting temperature will encourage your pool water to reach warmer temperatures throughout the afternoon. You should realize a gradual heat gain throughout the first few weeks of using the product. Does this sound like what you were expecting?

At this point most people will agree with me and realize that their EcosavrTM is working wonders for them, they just hadn't been quite sure of what to expect in the first place. Some of them also simply don't know how to use EcosavrTM, which is easily remedied as well.
Pools lose most of their heat through evaporation. About 75-80% of their heat, in fact. Evaporation will occur regardless of whether the pool is warmer, colder or the exact same temperature as the air. This is due to variables such as humidity, air movement and water movement.

However, adding a liquid pool cover like EcosavrTM or HeatsavrTM to your water will help lower this evaporative loss. As I mentioned, liquid solar pool covers have the ability to save about 50% of overnight heat loss.

50% is quite impressive, but it doesn't measure up to the expectations of a few folks out there who want a miracle cure for their pool water that will actually help raise the temperature above the air temperature without using a heater. If your daily air temperature is 80 degrees, and your overnight temperature is 60 degrees, there is very little chance that your pool water will remain at 80 degrees if you do not heat it.

Thankfully, there are ways to help boost your pool water warmth, in addition to using a pool blanket.

You can create a wind barrier and turn off any water features that may be increasing the disturbance of the pools surface water, as this type of movement increases evaporation and, therefore, heat loss.

You can use a dark pool liner rather than a light one, as a darkly line pool will attract warmth and, if you are using a liquid pool cover, that extra solar gain will be largely trapped in your water.
You can refill your water with water from a collected water source that is closer to air temperature than the water from your hose will be.

All of these ideas will help, but a pool cover is undoubtedly the best way to retain the heat in your pool. You can use a plastic pool blanket for great overnight coverage, or a liquid solar pool cover for 24 hour protection, they each have their benefits.


Posted in Retain Heat, General Information, Home Pools, Conserve Water    Tagged with evaporative loss, swimming pools, ecosavr, liquid pool cover, pool cover, pool, pools, swimming, results of using ecosavr, ada regulations, heat your pool, don't heat your pool, overnight heat loss, pool water, gradual heat gain, ecosavr tutorial, ecosavr tutorial video, evaporation, ADA Compliance, liquid solar pool covers, solar pool covers, pool blanket