Portable air conditioner less effective tonight, am I using it properly?

[CantStop1]

So I bought a portable aircon unit last year. The windows and balcony door in my flat (I live in London) open towards you rather than lift up.

I got the unit out last night and put it in my bedroom, with the hose pipe going out of the window. I clipped my curtains around it to try and seal the hose and prevent any hot air coming back in through the window. Last night it was brilliant - cooled the room right down quite quickly.

However, tonight, it just isn’t being very effective? I realised the curtains were covering the back of the unit so I’ve pulled the unit out from where the window is so there is more room now and so the curtains aren’t covering the back.

Am I doing something wrong? I know it’s hotter tonight and maybe I’m being impatient and need to give it more time to cool down (it’s been on for about an hour but I keep going in and out to check the room temp)??

It’s a lot hotter tonight and there’s no breeze like there was last night.

Air con units aren’t very effective unless the room is properly sealed other than the vent hose. Curtains aren’t going to do that. I suspect last night it was as much the breeze as the ac unit that cooled your room

You need a kit like this https://amzn.eu/d/06LpPGBt

Stuff the gaps with old pillows, sleeping bags, duvets or towels for now. It's very effective.

@WindyMillerDrinksCider what do you mean stuff the gaps? You mean to create a better seal around the hose?

Check that your tube is properly connected to the unit. Our hose slides into place onto the back of the unit and can get dislodged.

Also, double check that it is set on air con and not just the fan setting.

we vented ours through the wall like the old tumble dryers. Looks much nicer and works better.

Same here it’s just much hotter

Yes make sure it’s on Air Con setting and not Fan or something else .. I have made this mistake.

i also block gaps around the hose with pillows. Ours has the hose plus a slidey plastic rectangle as it is meant for sash type windows I think and ours open with a hinge ourwards. But we make it work.

Ours is working fine and we don't block the window although we should. It cools two rooms as we leave the doors open for the air to flow round but we do have a small house!

Check your filters aren’t clogged. Had this with the portable unit at work and the filter was thick with dust

You need to buy a proper seal. You can get them on Amazon for the window type you've described. They're approx £15 and will make a difference.

I will definitely buy a seal but just checked again and it feels like there’s hot air coming out the back where the hose connects to the unit? Is that normal? It’s definitely sealed!

Take the hose off and put it on again. Use some old Amazon box cardboard to make a seal round the window gap secured with sellotape

Take the hose off the back and check the seal. Ours used to partially screw in so it didn't pull out.

I recall reading that a regular, ducted air con can only cool a room by about 20'c at most. So if its 40' outside at the very most it will cool to 20's. A portable unit with no proper seal would have a significantly lower cooling capacity so it being hotter tonight will be a contributing factor too.

Are there any holes in the hose?

The hose will feel hot or warm to touch the air shouldn't be escaping from the hose.

It might be that it's got too hot for it to cope

I think they usually go to fan mode when that happens

you can also get insulation to wrap around the air hose. I have that, as well as a window seal. Still only lowers the thermostat about a degree or so, from 28 to 27 - it's new build, over insulation, lots of glass, etc. The walls just heat up and radiate inwards! But insulating the hose and sealing the window help, as do awnings to stop the sun getting to the window in the first place.

If you are blowing warm air from inside to outside, it will need to be replaced by more air. Where is that air coming from? Outside?

I’ve actually turned my portable aircon off this afternoon because I think it’s making my room hotter. It’s ridiculous - it’s blowing out hot air by the pipe even though it’s sealed. At this point I’d recommend not buying one!!!

But it has to replace the air it’s blowing out from somewhere. It must be coming in from outside or else your house would implode.

How big is your room?

Does it need to be drained? Some have a condensing tank

Portable single hose AC units rely on air being drawn back into the room to replace the air that they blow out of the window. It's the main reason that they are inefficient.

Dual hose units (rare in the UK) or split units are much more efficient but are more expensive and don't suffer from the same limitation.

... and I'm sitting here melting without either !

I had mine set to 23° by accident last night, doh!

@CantStop1 have you checked the filter and the water collection point?