On the home front, we’re finally considering adding air conditioning; several months each year it gets downright unpleasant, both hot and humid. Our home was originally built for central air; the hoses are hanging out the side of the house but we never installed the outside unit. The reason is that they’re really inefficient and expensive to run; my brother says his electric bill increases as much as $300 a month, cooling off the entire home just to cool even one room. Always wanting to learn new things, I started looking into alternatives.

The first candidate was portable units, but the overwhelming volume of negative comments about them made me not even want to go there: very inefficient, noisy, and really lacking in cooling capacity.

The second candidate was window units. They’re typically noisy, both themselves and allowing in outside noise, they’re a security concern, don’t look good (especially sticking out the front of the house) and in our case at least, a no-go because our windows are too narrow.

The third candidate was through-the-wall units. The concern again was noise, and cutting and framing a big hole in the wall.

Then I discovered a fourth type, widely used in Europe and Asia, “mini split” systems, where a small unit is attached high on an interior wall, containing only a very quiet fan and radiator. Refrigerant flows through two hoses through a small hole to an outside compressor. It’s virtually silent, the compressor can be hidden from view, the wall unit is small and unobtrusive, and no big holes are needed. A system consists of: an external compressor (already charged with refrigerant), the wall-mount unit, a set of hoses, control cables, and a remote control. This is where things get interesting.

While promising, because the unit arrives as separate pieces, it’s not as simple as mounting the boxes, screwing the hoses on and opening the valves. Humidity trapped inside the hoses freezes into hard pellets and destroys the compressor, so the air must be vacuumed out to boil off the humidity, so a pump is necessary. It’s also good to purge the lines with nitrogen, so between the two, it’s why nearly all mini split systems are installed by professionals. But because they aren’t all that popular here yet, HVAC guys seem to be taking advantage of the situation and charging $1000-2000 just for installation. Always looking for a challenge, I could almost hear Jeremy Clarkson asking “How hard could it be?” Turns out there are a few issues:

First, doing it myself would require a vacuum pump, hoses, a good vacuum gauge, and a source of nitrogen, running around $300. Second, installing it myself means voiding the warrantee – virtually no manufacturer covers a unit not installed by a pro. Third, most air conditioners require 230VAC, of which there was none nearby.

Buying my own gear isn’t that terrible, especially since the vacuum pump could also be used for, oh, vacuum-bagging composite parts. Also, for what the pros charge I could risk it, and if it ever broke, either fix it myself or just buy another unit – and still have spent less than having it professionally installed.

Regarding the power, air conditioners in general take a lot, at least they used to back when they were fairly inefficient. For that reason, running them on 115VAC was always a bit iffy, so manufacturers sell way more 230VAC units (read: like 10 times as many). The good thing is that they’re more efficient than 115VAC units, and because of improvements over the years, they’re getting seriously good at what they do, some cooling a bedroom for several months a year for only about $1 a day. The trick is running 230VAC to the unit, but our fuse panel was already full. Worse, even if there was space for another breaker, because it’s an older panel, replacement breakers are ridiculously priced. Wondering if I was stuck using a 115V unit, I noticed the 230-V breaker on the panel labeled “dryer” – “Hey wait, we have a gas dryer, well isn’t that convenient!” So the plan is to reroute that circuit over to where the remote compressor will go. That’s the plan for now, and the goal is to get it online before the seasonal misery hits, which is typically around the first of September.