Water-use explainer
Where the water goes
A swamp cooler uses water in two ways: the water it evaporates to cool the air, and any bleed-off it drains to keep minerals down. Evaporation can be estimated from airflow and the temperature drop. This explainer does that with every assumption shown. It is an educational estimate, not a bill or a sizing.
Estimate it
Evaporation, with the math shown
Estimated evaporation
Educational estimate. Bleed-off is not included. Not a water bill or a sizing.
Every assumption, labeled
- Gallons per hour = CFM x temperature drop / 8186. That is 1.08 BTU per hour per CFM per degree, divided by 1060 BTU per pound of water evaporated and 8.34 pounds per gallon.
- 1.08 is for sea-level air. Grand Valley air is thinner, so the same CFM carries less air and this estimate runs a little high.
- Evaporation only. Bleed-off water, which some coolers dump on purpose to keep minerals down, is not included and can add a lot.
- The CFM on a label is a rating. Real airflow is usually lower with dirty pads, a slipping belt or a closed-up house.
- Not a water bill, a sizing or a guarantee. Your water provider bills by its own rates.
In the valley
Coolers and the July peak
The 2023 Grand Junction Regional Water Efficiency Plan compares each provider's average July day with an average January day.
| Provider | July demand | The plan's explanation |
|---|---|---|
| City of Grand Junction | 2.9 times January | mainly lawn irrigation and home cooler demand |
| Clifton Water District | 2.2 times January | lawn irrigation, evaporative cooler demand and other seasonal use |
| Ute Water | about 2 times January | estimated to be home cooler demand and limited outdoor watering |
Ready to send it in?
One form covers repair, startup, winterizing and replacement. Photos from the ground or from inside help.