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Community and Q&A

Excess AC Condensate Issues

Roger_S39 | Posted in General Questions on

Installed 2 variable speed units in a new construction home and am having drainage issues resulting from the condensate.

Guessing, due to the extended run times, because variable units ramp up and down, rather than just quickly blast a bunch of cold air and shut off like single speeds do, the amount of condensate produced from variable speeds is greater than single speeds.

As a result,  the condensate draining to the backyard is creating a swamp that cannot continue to be as is.

Currently, the condensate pvc pipe for each unit exits the house and each makes a huge mess.

One discharges into a catch basin that is connected to a pop up emitter in the backyard.

The result is a permanently half full catch basin, a 20 ft 4″ corrugated pipe completely full, and a 3-4 sq ft mess at the pop up emitter.

One could dig a hole a few feet wide and a few feet deep at the pop up emitter, fill it full of stone to create a drain pit, and put a small hole in the base of the pop up, but one wonders if the outcome in a few days/weeks will just be another permanent mess.

The other discharge line drains onto sod near the AC unit pad and is also a muddy mess.

What do the experts/professionals in the world of HVAC do to successfully manage this condensate water. Surely there has to be a buttoned up professional standard procedure for this situation. Surely!

Any info would be appreciated.

Thank you.

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  1. Expert Member
    NICK KEENAN | | #1

    Where does water go when it rains? Send the condensate to the same place. To put the quantities in perspective, a really good dehumidifier might remove five gallons a day. If you get one tenth of an inch of rain on a 1000-square foot roof that's about 65 gallons of rain.

    Don't think of it as excess. Removing humidity is a good thing.

  2. walta100 | | #2

    Most HVAC systems main drain is to the plumbing drain system. Some systems have a emergency drain system that is only active if the main system is inoperative. The emergency drain often drain to someplace the homeowner would be likely to notice so they would be more likely to fix the main drain.

    One has to wonder if what you have noticed is discharge from an emergency drain.


  3. Jon_R | | #3

    Clay soil percolation rate can be .1" per hour. Over 3.5 sq ft, I get 42 pints/day. So it's possible that condensate alone is saturating that area.

    Dumping into a plumbing drain is an easy solution. It's not so much water that I worry about the waste this involves.

    1. Expert Member
      BILL WICHERS | | #5

      There is no “waste” here. The condensate is removed from the air by dehumidification. The water going down the drain will either get to the ground through your septic system leach field (if you’re on a septic system), or will get back into the natural world after it makes its way through the sewer system and the treatment plant at the end of the line.

      A leaky faucet can be thought of as waste, because the water went down the drain without doing anything useful. Water from condensate is the result, a byproduct, of a useful process (dehumidification), so running that down the drain isn’t waste. ALL water in the world is part of the natural system of things, even when it goes down the drain. Water is, in effect, always recycled regardless of where it comes from and where it goes to.


  4. Expert Member
    Akos | | #4

    AC units here always drain into house plumbing. Unlike condensate from a combustion appliance, the AC condensate is just plain water, there is no reason to pipe it outside.

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