Duo 14,000 BTU (12,000 BTU SACC) High Efficiency Inverter (MAP14HS1TBL)

I also have horizontal windows! I have the Midea Duo and I love it. Super quiet and efficient. The remote acts as a thermostat too. It does need line of sight and it’s a bit finicky but that’s my only complaint.

The 14000 btu midea portable with the “dual hose” keeps my west facing two car garage at 78 while I’m tinkering. A mini split or window unit would probably be a way better option though if that’s an option.

This question makes no sense to me? I have a 650sf apartment, and have two 14k portable A/C units (LR and BR). I live on the top floor with large west facing windows, so it gets toasty when it's hot. I run the LR in the afternoon around 3-4pm when the sun starts hitting the windows, and turn on the BR one around 7-8pm to cool that area down. One life-changing bit of advice I can give you is get a Midea Duo 14,000 BTU High Efficiency Inverter, Ultra Quiet Portable Air Conditioner (AMZN: $550!). This thing is whisper-quiet for the BR, so I can close the windows (no street noise), leave it on all night, it cycles on/off as needed with almost no noise. Honestly, this has raised my sleep game immensely.

I'm USA and that is an average price for a single hose AC unit, just know they are inefficient and blow about 30% of your expensive conditioned air out the window hose, but if sized correctly they will absolutely cool your room. So if push comes to shove you can sleep cool with one of these, depending unit size and room size. A better but more expensive option is a 'Dual' hose AC, or a hose in a hose which tend to be oval, these tend to cost a couple hundred more but have much better cooling. Also these duals dont cause a negative pressure within the house like a single hose unit does, which by nature will suck in all the hot air from every nook & crannies it can find - which also raises the humidity too.

£900.00 \[$1200\] seems way too high of a price, and google says room size 110m2 is about 1200sqft. A 11,000 btu single hose unit is not gonna get even half that size - I think they may be betting that Europe is not getting as warm as here in the midsouth.  The Costway units are heat-pumps as well, either way at £289 they look like they'd get the job done. I bought a Midea Dual hose heat-pump from amazon for $570 \[£425\] so that price point looks about right for a single hose unit.

Yep, I have 3 different systems, a Midea 14,000 duo portable heat-pump in the living room, a Midea 8,000 window heat-pump in the master bedroom, and a 12,000 mini-split heat-pump in the backrooms. I've had them all on an Emporia energy monitoring system for the last 5 years and they are all similar in operating costs considering the room dynamics and individual heat loads, basically too close for me to call when dealing with the 'real' world. The mini-split is the best at efficiency, but with the installation cost, it has a negative return on investment. With the newer technology on window heat-pumps going from 40F to 5F, I will be heading that way just for the $500 and 30 minute plug & play option - ascetics be damned. I only went with the portable duo because it was the only option at the time, plus a year ago I permanently mounted it in the window and got rid of the oval hose-in-hose for a COP boost. Plus a perfectly hermetical sealed system. Even though I'm retired from hvac and have all the equipment to install any system - I look at the ease of the future and the 12 year lifetime of these overpriced installed machines. Contractors just got too greedy with the stealing of rebates and tax credits from poor people that I hope the fire of hell will be a fitting end for them...

10,000btu would be over-sized unless it is an inverter, which it sounds like it is if there is a reported whine. Most can throttle down to about 30% of max, so you'd be good there - if it is indeed an inverter machine. Whines can be highly depended on your electrical & grounding system. So kinda no rhyme or reason if or when it can happens. I've had the Midea Duo portable for 3 years now and have no problems with any sounds- tho' I'm kinda old. When I owned my repair shop I had to get my son to tell me when I fixed a corona discharge whine on the old ass CRT televisions...

Depending on the diameter of the hose get a 1"x 10" board for about $10 and cut your own hose hole and screw the included window kit to it so it has the hose retaining bracket. My Midea 12k portable AC/HP has an oval dual hose in hose system that is 12" wide by 8" tall and I used a 1" thick piece of dense Polyisocyanurate Board Insulation from Lowes, $30 for an 8 foot sheet. I did not use the window kit that came with it as I pushed the hose out the window an aimed it down so it would not suck in freezing rain or snow.

I have both, the Midea is going to be best for your situation, it has more of a variance in capacity than the Hisense, Hisense tops out at 12000btu but is rated for 8000, Midea tops out at 16200btu but is rated at 12000. Also, the Midea has a drain pump to pump the condensate out which is especially important in the heating mode, specially if it is going to go into a defrost. Overall, I think the Midea just has overall better functionality and futures than the Hisense and is closer to a mini split. The Hisense is perfect for my smaller rooms though.

I have the Midea. Combined with the inadequate central AC in the bedroom it's in, the room got down to a lovely 62 degrees last night. This is in Alabama.

I have 2 of the Midea units. One for my main living area and one for a room above the garage. It was 98F here today and it kept the main living area at 70F, which is what we had it set to. Main living area is about 1100 sqft. The room above the garage is 550 sqft and it’s where we work out so we set it to 60F and it got it down to 65-67F. That room is not as well insulated as the main space. I’ve had them for 2-3 years now. They are very quiet.