Portable A/C - how much cooling capacity is too much?

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  #1  
Old 03-13-18, 12:02 PM
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Portable A/C - how much cooling capacity is too much?

I'm looking to buy a portable air conditioner for the 1-2 weeks each year where it actually gets hot enough to bother using one in the UK. I've seen several websites claim that using an overly powerful unit will negatively impact its cooling and dehumidifying capability, but my question is how powerful is "too powerful"?

I've tried a few online calculators and most seem to suggest I need ~2.2 kW of cooling in a ~12 m2 office with 2 people and 2 computers. I also plan to use it in the bedroom before bed, which'd be ~18 m2 with 2 people (requiring ~2.9 kW). Our living room is ~21 m2 (requiring 3.3 kW) but I don't think we'd use it in there much. Given this, which out of a 2.4 kW and 2.9 kW unit would you choose? I'm inclined to go for the 2.9 kW unit but would that be "too powerful" for the office and not work optimally?

Thanks for any advice.
 
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Old 03-13-18, 01:21 PM
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Welcome to the forums from the UK.

Since this primarily a North American based site.... we don't know what units you have available to you. I know here in the States it's very beneficial to use a portable unit that has two connection vent lines to outside. This type of unit offers the best cooling without venting the cooled air to outside.
 
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Old 03-13-18, 02:01 PM
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All the portable units I've seen are single-hose and are usually between 2 and 4 kW of cooling capacity. I've found a handful at a price I'm happy with but they range from 2.1 to 2.9 kW, hence my question.
 
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Old 03-13-18, 03:48 PM
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In my opinion..... you can't get a portable unit that is too powerful.
Those units are not what I would call performers.
 
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Old 03-13-18, 04:02 PM
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The problem with a single hose portable AC is that it is blowing air outside. The air it's blowing outside is your air conditioned air from inside the room which is bad. Then if air is leaving the room air must be coming in to replace it. The air conditioner is actually sucking hot air from outside into the room. So, you end up getting probably half the btu cooling power you would get with a window unit or two hose portable AC.
 
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Old 03-14-18, 04:42 AM
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100% agree with the above post. Please get a two pipe system. One pipe draws outside air in and the other pushes the the heated air out.
 
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Old 03-14-18, 04:59 AM
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I have a portable AC I use in my garage. While I could feel it blowing cold air it took a very, very long time to cool the room. I looked the unit over and figured out which air grates did what. One pair handles the air that circulates in the room and one grate was the intake for the air that gets blown outside (condenser). I taped a cardboard box over the condenser securely taping all the seams especially where it met the air conditioner. Then I attached a 6" diameter flexible duct to the cardboard box.

Next I took a piece of scrap plywood about 12" wide (you can use cardboard) and cut it to fit the window width. I cut two circles in the plywood. One hole is for the hose that came supplied with the air conditioner and the other for my DIY flexible hose. Now the air used to operate the condenser part of the AC is drawn in from outside and blown back outside and the unit no longer pumps your conditioned air outside. After making that modification the air conditioner worked 100% better at cooling my garage.
 
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Old 03-14-18, 02:13 PM
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I have yet to find a dual hose unit on sale online in the UK.

Considering the room sizes I mentioned and the fact that the hottest it usually gets is ~30 C (although our computers kick out more heat), is it really necessary?
 
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