Not what you asked, but you might check that:
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The central AC doesn’t need to be recharged. If it has leaked coolant and is low, it will drop in effectiveness.
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Or, even more simply, that the air filters don’t need to be replaced.
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You can’t improve insulation. Doing so is a one-off cost, as opposed to the ongoing cost of throwing more air conditioning muscle at the problem. Weatherstrip leaks, replace any single-pane windows with double-pane, etc.
I’d also add that ASCII has had some similar issues in the part, but that tends to have been ironed out by now via changes to onscreen typefaces.
For example, some old typewriters don’t have a “0” key or a “1” key because capital-o and lowercase-l looked similar enough and context was sufficient to let them be used in place of the corresponding number. This trained some people to do that, to the point that various software adapted to permit misuse of one in the place of the other. To this day, I can open up Firefox, and the following webpage will render green text:
Some other fixes were were made over time, like making capital-i, lowercase-l, and the pipe (“I”, “l”, and “|”) as more-visually-distinct characters in typefaces where this matters.
In the monospaced font world, “programming” or “coding” fonts, where not confusing the character in question is particularly important, place a premium on keeping characters like this particularly distinctive, even at the cost of trading off some aesthetic appeal or conforming to traditional typography or handwriting-like conventions for letters. You’ll get more-distinctive “.” and “,”, “O” and “0”, “l”, “I”, and “|”, “j” and “i”, etc.