Usually we have a living room we camp out in with a thick blackout curtain in the doorway, and a window unit in our bedroom. (My son has a window unit in his bedroom as well, but his door is always always closed, so it doesn’t factor in much at all.) That leave us with a dining room, third bedroom, tiny kitchen (opens onto the dining room), and two bathrooms that are hot as Hades.
This year, there was a snafu getting the curtain up, and I thought, "Screw it, let’s see what happens. I turned on the ceiling fans in the bedroom with a/c and in the dining room, and put a big stand fan about 7 feet away but pointing into the third bedroom. Then I opened the bedroom door and commenced to drinking so as to forget about my electric bill.
I was fairly gobsmacked to find that it worked. It’s a bit warmer in all the usual places, but not very much. And…my electric bill didn’t go up a whole lot either. (Which tells me that I was entirely correct that my husband never turned off the a/c in the rooms he wasn’t using before, anyway.)
So the only thing I think I’m doing differently is the ceiling fans, and maybe having my fan back a bit from the doorway provides more opportunity for warmer air to move out through the doorway? I can imagine that a close fan might inhibit airflow out.
I had a small house once that had central AC installed well after it was built, and it never worked well. It was also expensive to use. I ended up buying small wall units for the bedroom and living room, and saving about $40 a month on my electric bills over using the central air.
So I’m going to vote for getting a small unit for the bedroom, and shutting the living room unit off at night. It may pay for itself in a single summer.
Room air enters the AC unit at the front of the unit. Put a thermoter in the air flow going into the unit. Hold it there long enough to get a stabilized reading. Hold it in a way not to transfer heat from your hand to it. Cold air should be coming out of the unit most at the top. After you have a stabilized inlet reading take a reading of the air coming out of the reading. Both these points should be inside the air conditioned spaced.
5,000 btu units are very inexpensive. That’s the best solution for a 2nd room.
A flex duct could be fitted inside a window unit. It would require a custom fabricated fitting. A duct booster fan would push the air into another room.
It can be done, but it’s much too expensive and making it work would be a challenge. It wouldn’t look very tidy either.
Buy a 2nd window unit. Or consider a portable on wheels. Move it from room to room, as required.
Move and cools are not very efficient. They pull some of the air from the conditioned space for the condenser and exhaust it to the outside. Requiring unconditioned air from outside to replaced the exhausted air.
I have a 10,000 BTU in my living room and 6,500 BTU in the bedroom. They’re basically the same size rooms but the living room gets the afternoon sun and is open to the kitchen. This is a similar size to your place, about 700 SF, and it’s barely adequate for an old building with uninsulated brick walls in Cincinnati. If you’re in Atlanta or Dallas or somewhere like that then you’re probably undersized unless you’re in a newer decently insulated building (though if you’re relying on a window a/c my guess is no).
Air coming out of the unit should ideally be close to 50º though if the room is 80º or above then the air outlet may be closer to 60º especially if it’s also hot outside. Right now I’m getting 51º outlet with a 75º inlet while it’s 82º outside on medium fan speed with the evening sun shining on the unit and the dark brick wall around it. I’d consider that a fairly average load compared to a super hot day or a cool night. If your air outlet is in the 60s, you could have a clogged condenser coil outside blocking airflow, and it won’t be dehumidifying well either. Any unit more than a couple years old can have this problem, especially if you live near woods, cottonwood trees, etc. They can be cleaned with a decent spray from a hose (you won’t see the dirt on the outside of the coil since the fan blows from the back/inside), but you have to be careful not to use such a strong spray that you bend the thin metal fins.
Anyway, it sounds like a second unit is probably the best option unless your big one is in fact failing. The thing is, 14,000 BTU units are quite expensive, like $400+ and going bigger will only be worse. It seems that once you get over about 10,000 BTU the price goes up faster than capacity so a second 5,000 BTU (the typical minimum) unit is pretty affordable. The other issue with the big ones is they’re extraordinarily heavy, they could be too big for your window, and if you don’t have it already, they may need 240 volts instead of 120. 15,000 BTU looks like the point where you start seeing the higher voltage models. Portable/floor units seem to cause more problems than they solve, and they’re more expensive for the same capacity while still tying up part of your window (though admittedly not as much). I would not recommend that route (search the forum here for single-hose versus double-hose portable a/c for some info on the sort of grief they bring).
This is the style of window I have. I can’t imagine taking up half (?) of it with pipe and boards and tape and not being able to close the window or even slide the other side. It sounds like the whole thing is commited then. Plus I get the pleasure of an AC unit in my bedroom.
I’m leaing towards having a transom and fan built into the wall above the bedroom door, and getting a tall tower fan blowing into the BR. If it represents an improvement of a noticeable percent it will be a good solution. I’ve been surviving for years with the status quo after all.
And use weather strips wherever possible; in general, make sure that a room that’s closed is really closed, both to the rest of the house and to the outside. If you keep rooms closed when not in use, cooling the used area is going to be more efficient.
If you were going to do this, how would you alter your window to make that hole? Do you need a pro to do this? Can you use the windows while the unit is running (open them to some degree, and how much)? And can you take it out and plug the hole easily enough to opt out if you want?
It is a possibility but I’d like to know how others did with side to side sliding windows. My windows are in another post of mine.
That’s the type of unit I was suggesting NOT to get because they use indoor air to cool the condenser, blowing it outside (that’s why there’s just one hose, an exhaust air hose). That means it causes negative pressure in the room and throughout your whole apartment, forcing the hot air from outside to get sucked in through cracks, negating any efforts you make to install weather stripping. That makes it self-defeating, because whatever additional cooling the unit provides is partly if not entirely offset by the additional hot air being sucked into your home.
His window unit will be bringing in cooled fresh air at the other end of the place. So in his case, that’s a feature. The air will flow in just the way he needs it to.
But even if he didn’t have that, the problem you identify by no means negates the usage of the unit. It lowers the efficiency for sure, but his bedroom would be cool enough to sleep in, which is the point.
The OP has stated that being able to see out his window is a high priority. This is the only way to solve the cooling problem while maintaining the view. No matter how big a unit he gets for the other window, it’s going to have trouble cooling the bedroom. At which point he’ll put it on “max” which will close the fresh air intake and create exactly the problem you identified above - pulling hot air into the bedroom to compensate.
What? The fresh air intake on window units is a tiny little vent that’s maybe one square inch in size at best, and any airflow through it is purely incidental (air could just as easily blow outside as get sucked in). I’m not following your reasoning. Besides, wherever I’ve seen “max” on a window unit that’s only for maximum fan speed. There’s nothing else for it to control. Usually the vent is a separate switch or lever. It’s not like in a car where normal vs max mode changes between 100% outside air and 100% recirculated air.
Putting on max cooling will close the fresh air intake. And closing the fresh air intake will not mean the window unit will pull in outside air else where.
Well, I can only speak for the 2-3 units I’ve used over the years, but all of them took in a declining ratio of fresh air the higher you set the cooling power. When you got to “Max” you could hear the vent clamp shut, the air smelled different and the unit got enormously louder - it wasn’t just the fan blowing harder. But I’m sure there are a thousand different variants out there, and yours may very well work as you describe.
The important point is, that the unit will in fact make the place cooler than if you don’t use it.
The cooler air is on the floor.
If you are trying to circulate it from room to room, keep the fans near the floor near the door and pointing up. If the layout is right you may aim a fan on the floor at the exit from the room with the AC down the main hallway. Put a fan on the floor, near the door, in each room such that it draws air in from the floor level of the hallway. Point that fan upwards into the room.
Still a very crappy solution. Maybe open one window a bit, that is farthest from the AC equipped room. Keep all others closed. With the above fan scheme in play. Maybe just the bathroom exhaust fan if it located well. That takes the top layer air that is the hottest out.
If your main concern is keeping you cool while you sleep, consider getting a standing cyclone fan and point it at your bed from the doorway. Like this fan. It will direct a stream of cool air over you and you’ll likely feel comfortable even if the room itself is warm.