What's a Swamp Box?

One thing you notice as soon as you start driving around Tucson is the many  beige-colored metal boxes  you see sitting on the roofs of houses all over town.  Some look pretty neglected and rusted out.  At first glance, you might mistake them for air conditioning units, and they are, sort of.  They are often referred to as “Swamp Boxes” by the locals.  A Swamp Box is what the heating and cooling industry calls an Evaporative Cooler.  It works much like a home humidifier.  The cooler contains a basin of water and a rotating drum with a foam pad.  Air is blown over the wet pad and into the house to produce cool moist air.  With an A/C unit, humidity is sucked out of the interior air in the cooling process, whereas with a swamp cooler humidity is blown into the interior air.  Since Tucson is a desert climate with very little humidity, for most of the warm season, an A/C unit is of little use.  The locals who have lived with their quirky swamp coolers since the 1960’s, like to brag about how much more efficient and economical they are to operate as compared to air conditioning.  Well, I am here to vehemently disagree.  Mostly, it is guys who like to “tinker” who think these contraptions are so wonderful. 

First, the fact that the thing sits on the roof makes it very impractical and inconvenient to maintain.  Sure, everyone has flat roofs here.  “What’s the big deal about climbing up there at the beginning of each season and revving the thing up?” they say.  But, who wants to climb up on their overheated roof several times a season to make sure the cooler has fresh water running through it, that it is regularly back flushing all the scum, bugs and dust out of the water tray, and the motor and belts are in good working order?  Why are they on the roofs to begin with, you might ask?  Because the entire heating and cooling duct work in these homes is run through the crawl space above the ceiling.  With uninsulated brick walls and no basements, the attic crawl space was the most cost effective choice for home builders to locate the duct system.  So, if you live in a neighborhood that was built prior to the 1980’s you most likely will have a view of your neighbor’s roof-top swamp cooler from your backyard.  

Swamp coolers work fine when the air is dry and the temperature is below 85 degrees Fahrenheit.  But once the Monsoon season is in full swing, which is from late July through mid-September, a swamp box is pretty much rendered useless.  This is the rainy season in the southwest.  If you are familiar with summers in Florida, you know what it feels like when thunder storms roll through in the afternoons and temperatures are in the 90’s.  The heat combined with the humidity is almost unbearable.  If you are running a swamp box to cool your home, the temperature will not get below 80 or 85 degrees and the humidity will be high enough to make the inside of your house feel like a; swamp.  Bathroom towels won’t dry, and any books, newspapers or magazines you might have in your home will be limp and damp, too. 

By the 1980’s, as more people from outside of the southwest, and who were unfamiliar with swamp boxes, began moving to Tucson; home builders shifted to combined forced air heating and air-conditioning systems, along with construction methods common to the rest of the country.  You will never see a swamp box on a roof in these neighborhoods.  Although, you will hear some homeowners complain about how uncomfortably dry the air is in their houses when they run the A/C system before the humid Monsoon season.   A few old swamp box die-hards have created their own hybrid swamp cooling and air-conditioning systems in order to have the best of both worlds.  Others just leave Tucson in the summer months for cooler regions of the country rather than deal with the heat, humidity and the issue of swamp boxes vs. A/C.  My advice: Never, ever let a Realtor or your spouse convince you to buy or rent a home with a swamp box.   This is the 21^st century, for goodness sake!