Portable Air Conditioners: Not So Portable, Don’t Cool The Air

73 degrees? good luck with that.

73 degrees? Good luck with that.

The concept of a portable air conditioner implies that the device is portable, and that you can cool a room with it. They would be a wonderful tool if this were were true, but tests by our breezy and cool colleagues down the hall at Consumer Reports show that they compare unfavorably to window-mounted air conditioners in pretty much every way, and you might be better off with no air conditioner at all.

Usually people don’t go out and choose one of these units when they could have a window air conditioner instead. It’s only when building regulations or practical concerns mean that they can’t install a window unit that people get these. (Or maybe they just don’t know better.)

The reason why they provide such crappy cooling is just physics. A portable air conditioner uses a hose to vent exhaust out a nearby window, which creates a few problems: for starters, negative air pressure that pulls warm air in from other rooms as the conditioned air gets pulled in to cool the condenser, then vented out the window. With the entire motor inside the room with you, the appliance makes more noise than a window air conditioner. They’re also very heavy, weighing 80-100 pounds, and not all that portable once you set up the window venting mechanism.

Consumer Reports says that if you have no other choice, get the Honeywell MN10CES[WW], which wasn’t a terrible performer, and only costs $400. If you have any choice at all, though, go with a window unit: you’ll get superior cooling for less money.

Are portable air conditioner claims a lot of hot air? [Consumer Reports]

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  1. StevenB says:

    What this article doesn’t cover nor does consumer reports is a dual hose design portable AC unit. I have such a unit. I would like to see what is said when a dual hose in considered. =(

  2. oomingmak says:

    Agree 100%

    We had a portable AC in the apartment above our garage and it was useless even though the BTU claimed to be high enough to cool the space. On hot, sunny days it would just end up getting hotter and hotter even with the device on at full-power. It wasn’t cheap to run either — that thing could eat up a good $100-$200 a month in extra electricity. We ended up being happier with all the windows open and a couple of strong fans to move the air around and bring in the evening air when it cooled down at night. Waste of money.

  3. xvdgry57 says:

    It must be nice to live in a temperate climate where you don’t need AC.
    For the increasing demographic that lives in an apartment or has onerous HOA rules AND whose once comfortable neighborhood is miserably hot due to urban heat retained at night or just plain global warming these portable AC units are the only option.

    Not to say they are good; most I’ve encountered range from “pitiful joke” to “meh, I can make that work”.

    Before CU bothered to review portable AC units I had to do my own meta-inferential analysis of the options. Who’s that brand, what’s their reliability history with other products, which ones have the most online complaints (ruling out those with zero complaints; too suspect). A few other spooky metadata analytical techniques that could gey me a job at the NSA.

    (1) Get the most efficient model you can find; it saves money and they are historically the quietest.
    (2) Get ONLY what you need to cool the square footage where you will be during the time of day you will be there. Use it only where you are.
    ((a) smaller units working at night don’t have to fight solar heating so if are just cooling a bedroom at night you can easily get away with 90%~95% of the “required” BTU capacity and makeup the difference with fans.
    ((b) smaller units are usually more quiet.
    (3) If you are stuck with an apartment with tons of South facing windows invest in the most heat reflective window tint you can buy. The expensive “platinum” grade stuff from the big box hardware store. Even consider reflective mylar backed blackout curtains. If you have no shame aluminum foil flush against the glass is great too. This step can be the most crucial.
    (4) Buy a condensate pump. These can be had for ~$20 and work opposite of a toilet tank: when they get to a certain level the motor kicks on a pumps the water away. Got mine new from a refrigeration supply website for $18; whisper quiet and it was rated for 25′ head height. Place portable AC just high enough for gravity drainage to the condensate pump then route the drain hose wherever: outside, toilet, tub, sink, potted plants.
    (5) Get air duct insulating wrap and wrap the the exhaust duct completely.
    (6) Insulate and seal the exhaust exit (usually a window but I used a bathroom exhaust fan duct once) so hot air isn’t leaking in the cooling zone.
    ((a) For windows ensure you have a locking bar jammed in the frame to ensure that it doesn’t become an entry point for thieves.

    Portable AC units are a poor solution to architectural design failure or cheap builders but they are very much better than nothing.

  4. theoriginalcatastrophegirl says:

    glad i didn’t throw my money away on one of these. i used to live in a house built in the 1930′s and it had narrow crank out casement windows. the place had two wall unit room air conditioners but they couldn’t keep up with the whole house and i wanted a portable air conditioner badly but couldn’t afford it.
    right now, even though i have central air, i also have a window unit in my bedroom so i can ease up on the whole house cooling while i am asleep and save on power bills. it’s a $99 frigidaire from amazon and it works fantastically well

  5. Mokona512 says:

    I have used some in the past, and the ones that use the cooled air in the room to cool the condensor before exhausting are the worst. Due to nothing being 100% efficient, the cooling mechanism generates more how air than cold air. As it pulls heat from the air, it adds a significant amount of its own heat, and thus requires a high CFM, meaning, it is pulling out a ton of cool air from the room, and since houses are not 100% air tight, and negative pressures are generally difficult to maintain, hot air will always rush in from all openings in the home. It is a shame that some companies are still using that design.

    A proper design pulls in air from outside and sends it back out after using that to cool the radiator.

    Those designs are largely the equivalent of taking a standard window unit, adding a tank to catch the water, and then adding one hose to the back to exhaust the hot air, and another hose to the side intake vents to pull in cooler air from outside to cool the unit. Those systems provide similar cooling to a window unit but with more noise.