In defense of the swamp cooler: This Phoenix man uses AC and evaporative cooling in harmony

As part of the series called Throwing Shade, The Show brought you a conversation with a reporter based in Albuquerque. She’d written about how residents of that city were deciding to ditch their evaporative coolers in favor of air conditioning, saying their swamp coolers weren’t making their homes cool enough.

That conversation prompted a response from Mark Dix, who wrote to The Show in defense of evaporative cooling.

Dix lives in downtown Phoenix and has been here since 1995. The Show invited Dix to talk about his experience, starting with how he decides whether to use the evaporative cooling or AC systems in his house depending on weather conditions outside.

Full conversation

MARK DIX: Exactly. I think because of the extreme heat in Phoenix, we need to have air conditioning during certain months of the year, when the dew point is high, when it's more humid, typically July and August.

But the shoulder months of those hot months, which would be April, May, June and September, October, when it's still approaching 100 but dry outside, I can use swamp cooling. And during those months, my utility bills are dramatically lower.

MARK BRODIE: It requires, though, a certain amount of vigilance to make sure that your house isn't getting too warm and the conditions haven't changed to the point where you need to switch between the units, right?

DIX: Correct. And that switch is not something you do multiple times throughout the day. You, you pretty much, when it's dry outside, I'm running that evaporative cooling up through the end of June.

And then when I watch that dew point and see it's starting to rise, when the monsoon season starts. Even if it's not raining, we still have monsoon season because the humidity is rising. And then I'm switching over to air conditioning.

BRODIE: So how big of a deal is it then to try to figure out when is the right time to switch? [Does] it a matter of you're sitting in bed and it's like, I'm a little sweaty right now. It might be turned to time to go to the AC.

DIX: Yes. Some of it you just notice because the evaporative cooler is unable to take off 25 to 30 degrees from the outside temperature. So it would be, you know, in early July, it would be a 110-degree day. And my evaporative cooler is no longer dropping the temperature down to the high 70s.

Instead, it's like the temperatures in the mid-80s. Then I know that it's working too hard. And I also can just look at the weather. I see the, the dew point. And I immediately can see that it's high. And I know it's time to flip over.

BRODIE: What is the difference in your utility bills? And obviously it's not an apples-to-apples comparison here, but what is the difference in your utility bills in those months when you're using the swamp cooler versus the months you're using the AC?

DIX: It's dramatic. The big example would be when I was digging a basement under my house 15 years ago. I was not using air conditioning, because I had so many holes in my house. Huge holes. Kind of fits the purpose, right? I would cover up those holes with plastic during the night while I wasn't working.

But I was using every power tool I owned, jackhammers, table saws, everything. Using a lot of electricity, but using evaporative cooling to cool the house. And my bills were about $90 a month. I finished the basement, got it all sealed up, turned on the air conditioning, and my bills went up to $320 a month immediately.

So the power pull on AC is not to be underestimated. So trying to reduce our use of air conditioning is by far the single biggest way we can reduce our energy footprint.

BRODIE: I can hear people right now listening to you talking about this and saying, this sounds great. I'm not sure I can sleep if it's 78, 80 degrees in May or June. So I would imagine for some people like you, this works really, really well. For others, it probably wouldn't work so well.

DIX: I think it has to do with being a very different climate in your house. Evaporative cooling moves a tremendous amount of air, like high volume, through your house. So it's not windy to blow your hair back. But there's more visible air moving in your house. With AC, you don't feel the air moving. And so that is cooler in itself.

Also, using ceiling fans over our beds in other parts of our house is a very low energy way to stay cool. And then it's about maintaining the unit so that it is clean and running properly. And then the benefits are so great with energy savings that we end up being in a much better place and more healthy.

BRODIE: I would imagine also that the structure of your house — how big it is, how well insulated it is — that also probably plays a role into whether or not this would be an effective cooling strategy, right?

DIX: Most definitely. Air conditioning, you can really air condition any space, be it large or small, effectively. But it's expensive. Evaporative cooling if you're in a — is difficult in an apartment because you don't have control of duct systems and so forth. So it would be difficult to do there. But they do have, in smaller houses, if you don't want to put in the ductwork, you can use a window unit. Which literally is a larger version of an air conditioning window unit that goes outside of a window and that pushes that fresh air into your house.

And then you have another window at the other end of the house that you crack open and the air pushes through. Works very well in a small house. If you had a large, ranch-style house that was very spread out, those types of houses would probably need two air conditioning units anyway. Some of them use three.

Same token, you could have a swamp cooling unit on either end of the house to cover those areas.

BRODIE: Do you know of other people who use swamp coolers?

DIX: Only a very small number. I think it is really considered a dinosaur technology to most folks. And there are several reasons I would suspect for this. One is some of the issues we already mentioned of what people are used to. The control of a thermostat and getting that cold air immediately, and just being able to shoulder the costs and assuming that they have no choice.

Another reason though, I think is just that the people who install air conditioning units, it's just not a profitable technology. If they're putting in a new air conditioning unit in your house, at minimum, it's going to be $10,000. And if they're selling you a highly efficient system, it could be well over $20,000.

Evaporative cooling is only, you know, a couple thousand dollars to put in, and so it's less attractive to contractors. It's not something that they're going to be mentioning. And it's been deinstalled from houses much faster than it's being installed. So it's really something I think that we're going to need to return to with rising costs and a rising climate concern.

BRODIE: Well, along those lines, I mean, are you concerned that, you know, if it continues to get warmer here in Phoenix — let's say if, you know, 115, 120, maybe even 125 at some point is kind of a standard June or not an unusual June day. And an evaporative cooler is cooling you down 25 or 30 degrees, your house could still be close to 100 degrees.

DIX: Correct. So when you have those days that it gets up into the teens and 20s, you know, above 115, absolutely. You know that that wet T-shirt concept of the air blowing through it to cool you down just doesn't make as big of a difference. So that is really where air conditioning technology is — we're going to have to still have it.

Definitely not saying we're done with it. It's just that we can minimize the use of it. And so those shoulder months that used to be smaller because it didn't become 100 in Phoenix until June. But if it starts to become 100 in Phoenix in April, then that's all the more reason that we can be using evaporative cooling earlier in the year. And then using it later in the year, approaching Thanksgiving, still knowing that we will be using air conditioning during the hottest over in the teens and higher.