Water Supply Improvements

Having a large garbage can full of ice water in your room is a bit of a pain. I decided to modify the system to run off a garden hose, for increased reliability and to prevent late night stumbles from flooding my room.


The system is fed from a tap on the side of the house. The hose is ancient so the connection is a bit leaky, but a bit of tape stopped that quickly. I added on some pipe insulation (~$1.50) around the garden hose to make sure the only thing warming up the cold water is my stupidly hot room.

The water supply in Waterloo is typically from groundwater sources, so the garden hose tends to be quite cold regardless of season.


The hose insulation ends under my window. The remaining length of garden hose is coiled and wrapped with towels to insulate.

The garden hose is then connected to the vinyl tubing with duct tape, of course. It then leads through a small hole in my screen towards the fan. I must congratulate my landlord on the exceptional job he does on basic maintenance, such as exterior paint touchups.


The tubing feeding the system cold water can be seen at the bottom of the window. Water circulates through the heat exchanger, and the warm waste water is pumped up towards the roof.


Another small hole was cut in the screen for the warm waste water line. It then passes an old bird’s nest (a necessary accessory for any student ghetto) and leads to the roof.


The warm waste water is pumped onto this garish prefabricated roof, which covers part of the backyard. Hopefully, a side effect of this is a slight temperature drop on the roof due to evaporating waste water. This may have a minor effect on the outside temperature near the room.

You can also pump the waste water into your eavestroughs. This makes sure you’ll be draining to a location that won’t flood your basement.


The water eventually drains off the roof. If you’re of the Zen persuasion, the gentle sound of running water will lull you off gently to sleep. If you aren’t, it may drive you absolutely mad until you realise that the sound of the fan drowns it out anyways.


The water drains to the same garbage pail, which can be dumped on the lawn or used for watering plants, if I had any.

Homemade Air Conditioning Plans and Pictures
Original Design
Geoff’s Homemade Air Conditioner
Heat Exchanger Improvements
Water Supply Improvements
Technical Notes
Other Designs
Pete’s Homemade Air Conditioner
Anonymous’ Homemade Air Conditioner
Spencer’s Homemade Air Conditioner
Final Design
The Black Beauty

7 thoughts on “Water Supply Improvements

  1. This looks cool and all, but doesn’t the long-term cost of water make this bad? A lot of commercial air conditioners have a closed cycle, not needing anything other then power to run. If you add the water bill to the air conditioning cost, isn’t your air conditioner very ineffective?

    • Hi Philip – I actually ran the numbers at the time (see Technical Notes), and it’s cheaper. In terms of volume, people watering their lawn would use far more, far quicker. Regardless, at the time I would only run this at night before bed to prevent my girlfriend giving me hell. 🙂

  2. Greetings.

    I have been tinkering with something i would use for camping that does what your invention does.
    I have noticed that when you use a 12 volt or 120 volt water pump in between two copper coils-one coil in a cold place like the fridge or freezer or the bottom of a deep pond and the other strapped to a fan you can conduct the cold from one coil to the other.
    It works pretty well except you can never get the second coil colder than the first no matter how amny coils you string in series as the source coil.
    If your source coil( as i call it) is at 65 degrees your target coil (coil on the fan) will be at 65 degrees.
    Just get a small pump to pump it in a complete circle from one coil to the other and back again.

    • This is a great idea – the pond acts as a heat sink and will have effectively unlimited cooling capacity for the applications we’re talking about here.

  3. One other thing you can do is sink the source coil about 5 inches under the sand (in a moving stream).
    I have taken temperature measurements where i live and have found up to a 20 to 25 degree F difference,that coil can be considerably colder when its under cover of trees and in sand in a moving creek even in hot weather.

  4. Another thing for hot Summers would be to place a small “water feature” pump in the drain-off tank and run tubing underneath your cover and install “misting” nozzles. This can drasticall drop the ambient temp in the area served by the “misters”. I mounted a custom made plastic tank on a bicycle and ran a drink tube and 2 misters off of a standard automobile windshield washer pump and 4 “D” cell batteries. The drink tube fed water up to and just over the top of the drink tube and the mist nozzles produced a cooling mist from mid chest to my face. It doesn’t take much pressure to make the misters work really well.

  5. You could also drain this into a rain barrel. I am working on a system that uses a solar powered pump to push the rain barrels into the sprinkler system. With water in the system at night and a battery attached to store power on the off days you could close the loop by feeding the cool water in the ground back into your ac system. Keeps all of the water storage outside and uses the geothermal systems methodology at a lot less cost. I already have to blow out the system for winter so adding a couple of steps is not big deal.

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