5 HN users recommended this explainer4 months2020–2026score 4.5
Years with an HN recommendation, 2007–2026
The go-to recommendation to watch before buying a portable AC, cited in nearly every thread on cooling.
Technology Connections explains why single-hose portable air conditioners are inefficient and often a poor choice compared with window units. It details how the single hose pulls in warm outside air and wastes energy.
“If you are in the market for a portable AC I highly recommend you watch this video first” (HN, 2026)
If you are in the market for a portable AC I highly recommend you watch this video first: [this video] People seem to be catching on this and some brands now offer portable mini-splits ACs, I just bought this one (waiting for it to arrive though): [link] However they are still quite expensive.
Portable air conditioners are bad. All the hot components are in the room with you and it takes air from the room and blows it outside. Technology Connections has a good video about this: [this video]
If anyone is considering buying a "portable" air conditioner - the kind that rolls around on wheels - know that they are pretty awful. If you must buy one, at least buy a "dual hose" version. Single hose versions suck air out of your house, causing fresh, but hot, air to be sucked in through all the vents, gaps, and cracks in your house. Window units or "split" systems are far more efficient and work much better, at the downside of cost and installation fees. Technology Connections has a very good video (with perhaps excessive detail, but it is very interesting) about them, here: [this video]
not op but was in same situation for few years as in my region A/C is somehow luxury and a lot of landlords don't mount them. the issue with portable A/C is that most of the units needs to stay inside apartment, the cooling happens by compression/decompression of coolant, which produces heat and cold. so the A/C unit is producing additional heat that it needs to chill, which makes it inefficient. also these units are loud as fuck, most of them above 65dB. so if you are in need, look for units that have the ability to channel cold air to the house from outside. otherwise you should always avoid portable A/C as it is really inefficient. here's better explanation: [this video]
Some portable A/C units do send hot air outside, and some don't. The two-hose models AFAIK are the latter type (although the un-insulated hoses are wildly inefficient) [this video]
Cited in discussion of single versus dual hose units
No doubt those will be single hose stand alone units, the worst kind [Portable Air Conditioners - Why you shouldn't like them] by Technology Connections [this video]
Cited for why single hose portable units are worst
Generally nothing, but those are 1. loud[0], 2. very inefficient and ineffective[1], 3. in the EU there are no dual-hose units for whatever reason. I still use one but it's very far from ideal. [0] so loud that neighbours might complain, I had neighbours complain about my computer fans running 24/7. [1] [this video]
Portable ACs are borderline scams because the hot side is inside the room it's trying to cool, among other reasons[0]. [0] obligatory TC rant: [this video]
Rant explaining why portable ACs are borderline scams
Video list and Hacker News comment labels from HackerTube (prompted by @karpathy), released under ODC-By 1.0, built on the open-index/hacker-news archive. Hacker News data is provided by Y Combinator; comments remain the work of their authors. Video titles, channel names and thumbnails belong to their creators and are shown via YouTube. HackerTube Watch is an unofficial edition. Data export of 2026-10-31.
Plays via YouTube's privacy-enhanced embed
9 Hacker News comments
From the HN archive; up to 20 kept per video, favoring different commenters. Recommendations first.
Read more
Citations, criticism and jokes