The weather has been fairly up and down lately, with Horsham rapidly fluctuating between “not quite cold enough for the heater” and “fairly unbearable but not quite hot enough for the air conditioner”. Given that both our air conditioners are fairly expensive to run (one is a “wall wart” of significant age that’s permanently installed in the house we’re renting, and the other is a single-tube portable unit we put in my office in summers, so neither are particularly economical), we really drag our feet before giving in and switching them on.
Given that Horsham is on the boundary of a “little desert”, and is quite dry - most summer days seeing Humidity around the 0~5% range - it seems like the perfect place for evaporative cooling. Indeed most houses around here appear to have it (though there’s lots of split-systems installed alongside it), but we obviously can’t install a ducted cooling system in someone else’s house.
I did however notice that Bunnings has portable evaporative (“swamp”) coolers for $69, and you know what that’s just cheap enough to give it a shot. We used a very old portable evap cooler at Mum and Dad’s place years ago and hated it because it made the room very humid after a few hours of operation (before which it was admittedly quite effective), but that was before I found out that you’re supposed to leave the house partially open with a one operating, they’re not like an air conditioner where you shut everything up!
So tonight with the heat, off to Bunnings to take a look. Couldn’t find them, only the $99 12L unit and I was dead set on the smaller one to limit the price if it turned out to be a dumb purchase. Asked for help and found them, they had two left, but we only wanted one… it’s an experiment after all.
Brought it home, filled it up (it comes with ice blocks too which you’re supposed to freeze, not sure if that’s necessary really) and switched it on. It definitely doesn’t chill the house at ~33C as low as the AC does, but I do think it worked. I ran it while we ate dinner, then in my office for some time, and then had it on us while we watched TV in the evening.
I checked the power consumption of it, it clocks in at just under 70W, or basically not quite double what a single pedestal fan uses (at around 40W), and well below the ~260W the wall aircon draws.
I did not measure my portable AC, because it’s not connected at the moment. I do think there’s probably going to be diminishing returns with it as the temperature goes up, particular in my office, where the AC will frequently hit the thermostat temperature and cycle… let’s say it uses 210W (to make the math somewhat easy), that’s about 3x what the swamp cooler uses… but if it’s only actually on for 1/3rd of the time, that makes them even, and I would be a lot more comfortable under the AC.
There’s also the potential of using it to cool the air in the middle of summer, with the house shut up, and using the other AC units to extract the extra humidity. Will that work, or will we end up with a bathroom post-shower after a few hours? Not sure, but if the AC units can keep the humidity down, and it can provide enough extra cooling to get them to shut down sooner, it might be worth trying.