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New portable air conditioner already losing steam

TehMac

Diamond Member
I recently ordered a honeywell 10,000 BTU portable air conditioning for a studio (~150 sq ft) and in the first two weeks it was working really well. My abominably hot apartment was being kept cool very well, in some cases even getting down to the high 60's in a few hours (I usually come back in the evening when my apartment has become an oven, usually 7-10* hotter than outside).

Lately however, it doesn't seem to be getting the room as dramatically cooler as it was in the first week and a half of ownership (it's been about 3 weeks).

The kit came with a window seal, but the seal wasn't wide enough for my window, so I just held the hose outlet in place with my blinds and it was still an effective setup. I'm always conscious about making sure the exhaust hose isn't crimping and trapping hot air in the hose.

I checked the air filter and it didn't seem dirty at all. So what could it be? I'm fairly certain it's not my imagination...is there something I might be missing?

edit: didn't know where else to put this-- the AT hardware threads seem to be about computer hardware...
 
I've bought two portables, returned them both. Basically same situation, worked great for a few weeks, then stop working.
 
interesting. A neighbor of mine had nothing but good things to say about his, and it's been going strong for a while. I think there might be an end user/maintenance issue I'm just not picking up on
 
Verify that the exhaust is still held in place, and that there is not wind/breezes blowing hot air in from outside, since the window isn't sealed.

Maybe the first few weeks wind direction was different then it is now.

Is the night time temp higher now than it was then?
 
My portable unit had a water drain on the back, maybe yours needs to be drained?

There's a drain on mine, but there's no refrigerant leakage that I can see, or moisture on the floor. The manual helpfully of course didn't mention anything about draining schedules.

Verify that the exhaust is still held in place, and that there is not wind/breezes blowing hot air in from outside, since the window isn't sealed.

Maybe the first few weeks wind direction was different then it is now.

Is the night time temp higher now than it was then?

Yep, the macro temp is higher than it was a few weeks ago, but even last week, which was a cooler week, I was experiencing this problem. It's an interesting thought though
 
how cool would you expect if you have an open/unblocked window?

Even in warmer temps the place was effectively cooled to 67-68* quickly, now it has trouble getting below 76* even with open/unblocked windows
 
While portables seem to have quality issues compared to window units, placing that aside for the moment, it is critical that your hot air exhaust is not mixing back into the room. If you have to, cut a piece of cardboard and tape it to the window sill and seal that exhaust pipe up. Is there a dust filter? Check to see if it is blocked/dirty. Finally, close off any doors that you can to minimize the total volume of air to be exchanged by the air conditioner. Also, place the air conditioner so that the cool air end is exhausting approximately 1/3 down the longest wall (assuming rectangular room) in order to ensure reasonably good air circulation. Make sure that the cool air exhaust doesn't short circuit into the intake of the air conditioner. This can happen if proper air circulation isn't occurring in your room. Sometimes, the location of the portable air conditioner or a piece of furniture near the AC unit causes it to only cool a small corner of the room because it short circuits the cold air exhaust into its hot air intake.
 
There's a drain on mine, but there's no refrigerant leakage that I can see, or moisture on the floor. The manual helpfully of course didn't mention anything about draining schedules.

It's not refrigerant that is released, its moisture that is collected from the room. Take it over to the tub and open the plug and see if anything comes out.
 
Also, place the air conditioner so that the cool air end is exhausting approximately 1/3 down the longest wall (assuming rectangular room) in order to ensure reasonably good air circulation.

First off, thank you so much Tiamat for this very well thought out response. Maybe the AT gods bring you much favors. Unfortunately, the '1/3 down the longest wall' doesn't really exist-- my kitchen with the door frame juts outward and there aren't any windows along the way-- I could put the portable AC unit in the kitchen but I cook there, so I'm not sure the oven heat (when it's on) is a good idea. Also, the window that is in the kitchen tends to catch breezes that blow in-- I could probably direct the hot exhaust in a way that this wouldn't be a problem, but I haven't done that yet.

If you have any feedback on the idea, I'd love to hear it!

P.S., I slightly changed the exhaust angle on the window just now, and it seems to be circumventing some of that heat short circuiting you were talking about.
 
I think pics would really help. I bet it's not sealed enough. Also the longer you have the hose extended the more radiant heat it causes. To the point where it may not seem to work anymore. But even if it's short you can do what I did and throw a towel over the hose. The more folds the better. Helped a lot to insulate the heat coming off the hose. Seal every crack you can and put a towel under the door even. You'll be freezing after that.
 
I still don't understand the premise of the question. You have in effect an open window, knowledge that it has gotten significantly warmer lately, and wonder why the room isn't staying cool?
 
You want a good seal. Just hanging the hose thought the blinds with window open and ways for hot air to come in won't work well. Also you want to locate condenser and compressor intake and pipe that outside too otherwise you are sucking conditioned air out and hot air in.

I have a 1ton (12k btu) for my ~90sqft office and it works very good. It keeps the hall cool too and I just point fans where I want cool air. The return vent is near too so I can run the furnace blower.

It helps the whole house for moderate heat like up to 27c or so. 30s it will still work for the office and hall and bedroom somewhat but I'd want central ac for that.
 
10kBTU for 150 sq ft.

EPIC!!@!@!one!!!!!two!!!!!!!

With this type of vented AC unit, even that is a bit undersized. I used one in a 100 sqft office, and it simply couldn't get the temperature down below about 80 when outside was about 95.

This type of unit vents a HUGE amount of hot exhaust through the hose; of course, the air source for this is your already cooled air. The result is that hot, humid air will be sucked in from outside through any crevice and crack. This means you can delete about 50% of the rating, as 50% of the cooled air goes straight out the exhaust and brings in fresh, hot air.

If operated in a sealed room, they will generate a vacuum and any small draught will become a gale. Seal the room too much, and you'll put a lot of pressure on doors and drywall from the vacuum, and you'll stop the thing cooling as it won't be able to pull enough cooling air.
 
if you aren't draining the condensed moisture from your room, then that is a problem. AC units condense the air on the coil and that moisture runs off down a drain or into a holding tank, just like a dehumidifier. If you haven't drained any water, then its past time to do so.
 
You don't normally need to drain water from this type of vented system.

The condensate is pumped onto the hot condensor coils where it is evaporated into the exhaust stream.
 
You don't normally need to drain water from this type of vented system.

The condensate is pumped onto the hot condensor coils where it is evaporated into the exhaust stream.

good to know. Thanks for correcting me on that 🙂

Slag
 
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