Using Condensation Water from HVAC to Fill Pool

12 years ago

Hi All:

Does anyone see a problem with collection the condensation from the HVAC lines in a rain barrel type container and using that water to re-fill pool when it is low. My concern is that the chemical balance of this water might be off a bit, but was just wondering if anyone had a bit more knowledge about this. Thanks.

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Cesare Beccaria

3 years ago

I just rerouted the condensate from one of my two A/C evaporators (the other was too far) and an Aprilaire dehumidifier. PVC pipe painted to match a downspout brings the condensate from the 2nd floor attic to a rain barrel I've set up to catch it. Hose connected to the rain barrel faucet allows me to empty the condensate into the pool--and then hide the hose when I need to. My hope was to have enough to keep the pool topped off with 7.0 pH water (pure water is 7.0; our city water is 8.2; ideal pH for plaster pool is 7.2-7.8). Initially I collected the condensate in a 5 gallon pail for testing.

Turns out the water has a pH of 5.8, which I learned is due to carbon dioxide dissolved in the water from the air. That's not a problem. In fact the small amount of 5.8 water will barely raise the pH of the 15,000 gallon pool. Right now, I'm getting only about 8-10 gallons a day, but this is fall, and the AC runs less than summer. I should get 12-15 gallons in the summer. I don't know if that will keep the pool topped off, but it will help with both quantity and pH.

My other water tests showed, not surprisingly, -0- chlorine, -0- calcium hardness, -0-total alkalinity, -0- salt, and -0- cyanuric acid. CDC recommends treatment of AC condensate if used for other than watering plants and other applications that don't require potable water, as the AC evaporator can carry in-home viruses and bacteria. Well guess what? A swimming pool has built in water treatment: chlorine. I use a salt water chlorine generator and keep the pool at 4-6ppm chlorine level, which is well above CDC's recommended minimum of 2-3ppm (CDC is only concerned with health issues, while pool owners also want to prevent algae.)

Reuse of AC condensate is likely to become more important in the future. Consider in Houston, there are about 2 million "housing units" and 110,000 business in Harris County according to the Census. Just consider how much water is created by AC units and then piped right into the sanitary sewer system every day at 10 gallons per household. 20 million gallons--and that's just Harris County Texas. I know a few people who capture the condensate and use if for gardens (5.8pH is perfect for most flowering plants.) There are 82 million single family homes in America. Do the water math and see how much we're throwing away every day. The cost of routing AC condensate out to a container instead of into the sanitary sewer would be almost zero for new construction. It cost me $150 for the AC guys to do it. I know I won't live long enough to get my money back in savings on my water bill and reduce use of muriatic acid for pool pH. I just wanted to know if it would work. I'm doing a tiny bit to save water.

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Comments (7)

Chris
12 years ago
I would want to test that water before putting it in the pool. My main concern would be that it just wouldn't be nice clean water and may well collect a decent amount of dirt/dust along with it.
c9pilot
12 years ago
We fill our pool from our 1500gal underground cistern that collects all the rainwater from the roof. Yes, we get some dirt and stuff, but that's why we put in chemicals and have a filter and a vacuum.
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huskyridor
12 years ago
Open up your evaporator coil in the attic sometime and wipe the inside floor base, it will have organic slime aka algae.
I would not recommend this manner of generating make up water.
On my pool I keep a 2" threaded cleanout plug in the female threads of my overfolw and trap rainwater. if it rains so much that the level attempts to touch the morter base of my coping I release about a half an inch and keep the extra 2 1/2" over my normal water level of an unplugged overflow grate.

C9, I like your idea for regular sized pools.
Mine is to large, I don't think 1500k would even raise my level a quarter inch.

See ya,
Kelly
keithw
12 years ago
I have been draining my AC condensation into my Koi pond for many years. It does a great job keeping it filled and the quality of the water is fine. You should clean the pan once a year by wiping with bleach and letting bleach run down the drain pipe.
tcarroll2
11 years ago
Just to bump this conversation, I noticed that I am generating about 15-20 gallons of condensate a day (I generated about a half-gallon in approximately 45 minutes to an hour) and I am thinking I will route my condensate line to my pool. The condensate should be clean enough that it won't be too much for my pool filtration system to handle. I dump about a cup of chlorine bleach into the plumping once a month to keep any growth from building up and the pan stays really clean. My condensate leaves the air handler pan and drains into a pump housing where a sump pump pushes to the water to the outside of the house and onto the ground. I have approximately 16x32 custom shaped pool that loses about a half inch of water nearly every day to evaporation. I was thinking if I can put in about 20 gallons of water per day from the condensate that should reduce my water bill considerably.

My concern is that my pool is salt water and that amount of water (potentially 140 gallons per week) will dilute my chemicals. Then again, I am doing that with the garden hose anyway. I'm not worried about over filling because my pool overflows to a drain that goes to the yard.
Michael Merley
4 years ago
You’re making distilled water from the air. If you want to clean the apparatus, the water will be about as clean as you can get…