this post was submitted on 07 Jul 2026
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hmmm
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They're talking about your whole house - by venting the PC to the outside, you're creating negative pressure in your house. Even with all the windows and doors closed, this will draw in outside air from somewhere.
While that might technically be true, in practice that volume of air is so small it’s inconsequential. There’s already a floor AC unit working by a similar mechanism - it exhausts hot air out the same window gap as the PC.
Practically speaking, this setup made a massive difference in my apartment’s temperatures during the hotter months. I can even use it without AC when it’s balmy, maintaining a comfortable temperature instead of baking in my office.
ACs do not transfer air from indoors to outdoors. Unless you have one of those single-hose "portable" units, which do not work very well, for the same reason. The effectiveness is going to be based on the temperature of the "replacement" air. If it is meaningfully cooler than the air you're exhausting it may work, but at that point why not drop the AC and just cool passively.
Using a portable -one hose- AC give me about 5 degrees delta in half my small house during the EU heatwave, in my case improving on passive cooling by multiples, so your last sentence just sound like ' I've never felt the effects of portable AC' to me. probably pretty common in the US, but EU houses often dont come with AC preinstalled.
I get that it's a dumb system, and I even knew before I bought this one hose monstrosity, but it's what is available to us here right now, and the fact that a split ac or window ac or 2 hose airco system (there was 1 model available to me locally, and it was sold out) is way more efficient doesn't magically make the one hose version work bad. It still uses the compression cycle for refrigeration, which is very powerful even when used inefficiently.
It is a portable AC unit.
I see portable ACs with a single hose as single room ACs. The room with the AC is cooling and pulling air from the rest of the house. That air is being replaced by outside air in those rooms.
But yeah, passive cooling is always good to do. Even with the best AC.
I have added a second hose to my portable single hose AC. Just a hose that is "hanging" against the input part of the AC so if there is negative pressure, the air will get sucked in directly into the AC.
You can definitely work it to your advantage in some situations. Last time I used one it was in an old apartment building which had AC only in the common hallways. Our unit's giant windows and about 10,000 coats of paint on everything made the exterior walls functionally airtight compared to everything internal to the building, so creating some negative pressure pulled in "free" conditioned air from the hallway. The only downside was turning our apartment into a sink for everyone else's cigarette smoke and cooking smells lmao
What a weird statement to keep repeating when it has such a big exception. "ACs don't do X unless its one of the most common types of AC."
ACs clearly do X, just not most of them. A lot of them actually explicitly do exchange air with the outside, because single hose portable types are widely used everywhere. They aren't ideal, but they are very common and are indeed "AC."
But isn't the easiest point of entry the AC unit?
The ac is t taking air in from outside, it's two different (and isolated) air routes. It takes in air from inside the house, cools it, and puts it back into the house. The outside air loop takes in outside air, heats it, and dumps it back outside.
These two loops never mix, at least on a residential system. Commercial is a different beast that does use external intakes.
Right. I confused evaporative coolers and AC for a moment. Thanks.
Not unless your house is like a space habitat. Homes have tons of gaps that air can seep through.