We have four window units in our ancient house. You're never going to get 35 years out of a newer unit. We have a great 12,000 BTU Frigidaire that does a good job keeping about 850sf cool (10' ceilings, no ceiling fans), and an 8,000BTU GE in our kitchen (14x16, with 10' ceilings) that will almost run us out of here because it's cold... We chose it because we cook all the time, and use our oven, even in the summer. It keeps up with the extra heat from the oven, plus our west-facing kitchen with two 6' windows.

I went on "Nextdoor" and got a free window unit, but's it's an old one. Then a free LG roll around unit on CL.....which has a hose to put in a window. That's the one I'd recommend. If your hot and want to sit in another room, just roll it to where you are. :0)

We bought a portable a/c last summer. It's the first time we've really needed one. We have windows and doors on all sides, and there's almost always a breeze coming in. But it's been getting hotter and hotter here, and with the humidity we broke down and bought one.

A portable unit requires venting through a window, so even though it can be moved from room to room, it still needs to be vented. The best place for ours is in the dining/livingroom area and it's vented thru the sliding door.

They don't cool as nice as a window unit though, but there isn't a window that we wanted to put the a/c in. Too cold for our bedroom, and didn't want to block the kitchen window over the sink. The patio door is the most logical.

As Jasdip said, portable units don't cool as well as a window unit but they're better than nothing and good for special needs. Keep in mind you have to empty the water catch cup ongoing. The last unit I bought was a relatively cheap unit, ($125 or less as I recall) and has a remote control which I REALLY appreciate. I have it upstairs in the small bedroom and blow it out into the hall and living room. It's about 5000 BTU, replacing an 11k or 12k unit and cools just as well if not better than the old unit and it's SO much lighter that it's manageable for me now, even as crippled up as I've become. It's also way quieter than the other. Basically there's not a lot of difference between units so I wouldn't get hung up on buying a particular model or brand. Get a good price and enjoy it. I look at it this way, I could have paid $400-$700 for a unit or $100, If this lasts 1/4 to 1/7th the time of the more expensive unit, I'm at break-even point. I've got at least 6 or 7 years on this one. I hope it'll keep going strong for a long time yet. But if it dies, I can go to Aldi or someplace and get another unit to keep me cool. If you have an issue with physical size then the measurements should be a determining factor. For me, it's a window unit and makes no difference.

These are terrible energy hogs. I was astounded when we replaced two through-the-wall units with Mitsubishi mini-splits on Maui. Our electric bills dropped by 2/3. They cost more to buy -- and even more if you need an installer, but they are cheaper to run and are totally silent. The old units became health hazards very fast. Mini-splits have separate the components, with the blower inside and the condenser outside -- like whole house A/C, but with minimal or no ducting. (They cool *and* heat.)