I have been considering capturing my HVAC water for gardening purposes for some time. This is not a new idea.

But I was wondering how MUCH water I would capture, and whether it would be worth the effort.

First, note that I live in the southeast USA, where it is very humid. So the HVAC does run and my HVAC can pull more water out of the air than, say, someone in Arizona.

My testing opportunity came yesterday, when the fan motor on my 4 ton HVAC went out at the house during the afternoon. This is a minor repair ($48), but it will take me 36 hours to get it done.

In the meantime I put my portable AC unit in my bedroom and closed the door. Its about .75 ton. It was purchased because I have a two story house but only 1 HVAC unit and sometimes it gets warm upstairs. This unit can be moved from room to room as needed. Its also very handy when we lose power or our HVAC dies, changing HVAC repairs from "crises" to "annoyances that I can take time to fix".

This unit is different from some that I have seen in that it has an on-board container to hold the water, as well as a drain line that can be activated by pressing the nozzle into a second position.

for this test I used the onboard container. In 1 hour it "produced" slightly more than 3 cups of water. It would take about 5 hours to get a gallon.

This is of interest to me for 2 reasons.
1) we lost water pressure during Ike, but I had a generator.
2) It implies that my 4 ton unit "might" make as much as 1 gallon per hour when its running. (this partly depends on how humid it is inside the house, I'm assuming diminishing returns would apply, but that new humid air would be cycled in continually through normal life activities)

Right now my AC drain goes back into the municipal water supply, as most newer homes do (the secondary drain does exit the house per code). its amusing to think that the city of houston may get a million gallons of water per day injected into the system for free. I also can think of implications in the future where electricity might be easier to get than water.

the upshot of it is that if I'm going to stay here, it would probably be worth a few dollars in PVC pipe to route the water out of the attic and down to a rain barrel.

Oh by the way, after I ran the test I engaged the drain line and put it in a 5 gallon bucket (the onboard container will only hold 1 gallon and then the unit shuts off automatically).

This morning there is about 3 gallons in the bucket, which is amusing in the context that the 1 gallon per person per day rule means I need 5 gallons per day to survive. It seems I would have that covered, assuming I had plenty of electricity. Of course, that isn't likely.

This is only an amusement for me at this time. I don't take any of it very seriously.

I wonder how clean that water will be, though I suppose if there were dirt/mold in the ac system it would be just as bad coming through the duct as drinking it.
Mine is in the basement so I can't drain out side to catch it.

True. There are those purpose-built atmospheric drinking water condensers that can be purchased with a small solar array, making for a self-contained water generation system (YMMV of course, depending on how much sun and humidity is typical in your area). I've pondered one of those units myself, less for emergency purposes and more for generating everyday generation of purer drinking water that doesn't have chloramines and their byproducts, flouride, and other contaminants that municipal water contain.

I would certainly purify any condensate from my A/C before drinking. No telling what kind of slime or mold is festering in the system. However, if your A/C can make enough water to make a practical dent in your garden's daily water consumption, seems like a win-win.

We've had an unusually cool summer here in Southern Cal. With the number of times I've run the A/C this summer, I think I've made enough condensate to keep a small shrub alive. Think Kevin Costner in Waterworld and his tiny citrus tree.

Being in a humid area, I have had similar "ponderings".

This afternoon I was visiting a co-workers home because he was proud of his handiwork erecting a privacy fence around his back yard. He'd borrowed by tractor to auger the holes and wanted to show me the final results.

Walking past his AC unit I noted a gallon bucket under the drip pipe. It was full. I asked how long it took to fill up, but he didn't know. He did say they used it to make concrete to fill the post holes. He said it was full by the time they'd finished mixing the bag, pouring the concrete and getting the next pole plumb and ready.

I was pondering starting a thread similar to this tonight!

Clearly it can produce a lot of water every day that it's hot enough to run the AC.

The water is being condensed from vapor, so it is clean for a time. Right? If a person could sterilize the coils/collector/drain system, and do it periodically, I don't see any reason why the water would not be safe to drink.

But, better safe than sorry.

In damp conditions a dehumidifier, a device optimized for gathering water out of air, more efficient in terms of amp-hour per pint than an air conditioner, can get you significant amounts of water. But air is [not] contaminate free. Dirt, dust, bacteria, algae, even protozoans, can travel by air and end up in the water dripping from the the condenser coils.

A dehumidifier, or AC unit, can collect water for you out of thin air. But condensate from AC units is notorious for supporting slime, mold, and crud so you are still going to have to filter it.

I guess that if you can run an AC unit, or dehumidifier, and have use of them for other reasons, and you happen to be shy of water, then you get water as a bonus.

Left out a word and it confused the message. Better now.

Such units exist. http://www.air2water.net/products.html Standard disclaimer -- no affiliation, that's just the first link I found.

Effectively, you're producing distilled water. The AC unit turns water vapor into water. http://www.ianrpubs.unl.edu/epublic/live/g1493/build/g1493.pdf

I would not want to drink the water that comes out of the pipe for the reasons you state, but if it is available and I don't have a ready source of water other than out of a ditch -- I know which one I'm going to drink.

There have been times in my life that I would have been thankful to have a bucket of AC water available.

Thats pretty much how I feel about it. Bonus water.