Is 5,000 BTU really enough to cool down a humid apartment?

A 5,000 BTU unit is likely going to struggle in an older building with drafty wooden windows and 35-degree heat waves. While those units are great for small, well-insulated bedrooms, they aren't designed to combat the heat load from an oven, high humidity from indoor laundry, and the heat gain from being on an upper floor. In an old building like yours, you're losing cooling thru those window frames almost as fast as the machine can produce it. Since you're dealing with humidity levels hitting 70%, you realy want to push for an **inverter compressor** model if possible. Unlike traditional units that just kick on and off, inverters run constantly at lower speeds, which is way more effective at pulling moisture out of the air. If you stick with a basic 5k BTU unit, it will likely hit its temprature target and shut off while the air still feels damp and heavy. Your cat will definatly feel that difference.

If the property manager is dead set on the 5k unit, let him install it but keep your expectations low. You’ll prolly need to use a floor fan to push the cold air from the living area into the bedroom, as a small unit won't have the static pressure to move air through a doorway on its own. If it can't keep the place at your 23-degree target during the next heat wave, that's your leverage to ask for a 8,000 or 10,000 BTU upgrade.

Also, try to limit the oven use and laundry hanging during the hottest parts of the day. Those two things alone can add several thousand BTUs of heat load and massive amounts of moisture that a small AC simply isn't equipped to handle. If you can get a unit with a digital thermostat rather than the old-school dial knobs, you'll have much better luck maintaining that specific comfort zone for your senior cat.

Have you ruled out just changing your habits before you fight for a bigger unit? If you're still running the oven and hanging wet laundry during a 35-degree heatwave, even a 10,000 BTU unit is going to feel like it's failing. You're basially fighting against yourself. Have you tried doing your laundry at a laundromat or using a slow cooker instead of the oven during the peaks? A 5,000 BTU unit is acutally better at dehumidifying a small space because it runs longer cycles; if you go too big, it'll short-cycle and leave your place feeling like a swamp. Might be worth seeing if basic lifestyle tweaks bridge the gap first.

Totally agree with the others. A 5,000 BTU unit is going to be running for its life in an old building like that. One thing everyone forgot to mention is the drain hole. Most of these small modern units are designed to splash the condensate water onto the condenser coils to help cool them down, but with 70% humidity and wet laundry inside, that pan is going to fill up instantly. If the unit isn't tilted slightly backward, you'll end up with a puddle on your floor or inside your wall becuase it can't keep up with the drainage.