There’s a lot of debate over how much you can really save with evaporative cooling versus regular A/C. This is one of the reasons I created the Evaporative Cooler Forecaster app. It’s a free download from the Apple™ and Google Play Store™ that tells you when your swamp cooler will be most effective based on your weather forecast and personalized comfort settings. It even estimates your potential energy savings!

This debate can get surprisingly heated 🥴!

I suppose it’s hard to keep a cool head during a heat wave which can lead to uncomfortably high utility bills.

It’s definitely possible to save energy with evaporative cooling, but there’s a catch. Because evaporative cooling relies on outdoor weather, your savings will vary. Hot and dry climates benefit the most. In humid climates, however, evaporative cooling is mostly ineffective.

The key to maximizing savings is to use your evaporative cooler alongside your regular A/C. The strategy is simple: switch from A/C to your swamp cooler whenever the outdoor air is dry enough for it to work well. A swamp cooler uses far less electricity than a regular A/C, so the more hours you can offset your A/C use the more you’ll save.

This is where paying attention to the weather forecast becomes essential. As a general rule, when the outdoor dew point rises above 50°F (10°C), a swamp cooler won’t be able to keep your home comfortable. This is another reason I created the Evaporative Cooler Forecaster app — to take the guesswork out of watching the weather. Instead of trying to interpret dew points and humidity percentages, the app simply tells me when the cooler will be effective.

Using the app has helped me maximize my savings by minimizing my A/C usage. Here’s a screenshot from the app showing how its recommendations for a few days:

The app labels upcoming hours with “COOL”, “FAN” or “OFF.” This shows whether the cooler will work effectively (“COOL”), if it’s cool enough outdoors to just use the fan-only mode (“FAN”), or if it’s too humid/hot and should remain “OFF”, meaning it’s time to switch to A/C.

You can see this creates a “hybrid” schedule. On Monday, the cooler is effective for over 7 hours during the hottest part of the day. But outside that window it would be too humid indoors so I’d switch to A/C during those “OFF” periods to stay comfortable.

That humid period only lasted a couple of days. It was followed by an unusually long, unbroken stretch of almost 30 days of very dry weather, which led to some serious energy savings.

Let’s look at the chart of my home’s daily energy usage from my utility company for June 11 through July 13, 2025:

You’ll notice that the energy use is very steady and low for most of the month. Then, there’s a huge spike starting July 12th, when humid weather returned and I had to switch to my A/C. The difference is dramatic. My daily energy use jumped from about 28–30 kWH up to an average of 70 kWH once I switched to the A/C.

That’s a savings of 40 kWH per day!

But that comparison includes my home’s baseline energy use for things like lights, computers, and the refrigerator. To get a true, apples-to-apples comparison of just the cooling systems, we need to isolate the energy used for cooling alone. After doing the math, the difference is even more stark:

• Swamp Cooler: 8.4 kWh per day
• A/C: 48.4 kWh per day

That means my A/C uses 576% more energy than my swamp cooler to keep the house at the same temperature. Put another way, the swamp cooler uses only 17% of the energy of the A/C.

For full disclosure, I keep my A/C thermostat at a conservative 78°F, which I find comfortable.

So are these savings typical? No, because there’s no such thing as “typical” savings. Your results depend entirely on your local climate. I live in a very hot, dry climate (the Coachella Valley in southern California) where summer temperatures regularly top 115°F (46°C).

Your climate is likely different. That’s why the Evaporative Cooler Forecaster app uses your local forecast and historical weather data to estimate your own potential savings.

It’s all about using the right tool for the right weather. By cooling your home more strategically, you can take control of your summer utility bills and stay comfortable all season long.

Check out the Evaporative Cooler Forecaster app and see how much you could save!