do the portable room a/c units work?

[RB]

Looking for reports of suitability from people who've used one of the common (Home Depot / Lowes ) portable air conditioner units. Need to know how good a job they'll do cooling a room.

Judging by what I know of thermal principles, the can't work. Where does the heat go? We know that to cool/chill air, you remove heat from it. In other systems, the heat is "pumped" outside. With the self contained unit in the room, seems like it could never get ahead because it's not isolating the heat anywhere.

Additionally, most of your air chillers have dehumidifcation as a by-product. So where's the water going in these units? Maybe they've got a concealed bucket you have to go dump periodically.

Anyway, I'd like to get a couple for use during power outages when we're running on our gensets, but need to know first that they really work. Otherwise, I'll use window units.

[Wayne Boatwright]

On Fri 09 Sep 2005 10:32:10p, RB wrote in alt.home.repair:

These units are ducted out of a window using a flexible duct similar to a dryer exhaust. Most have a tank that collects the condensate. Some are available with pumps that pump the condensate out the window through a small tube.

[Appliance Repair Aid]

G'day,

Both ways now. Some draw air from the ( 1 ) room for the evap and cond coils, many newer ones ( 2 ) draw outside air in one hose and blow the cond air back outside with a second hose.

These units "barly" operate cooling a room when compared to a window unit, but they will cool. JMO!

( 1 ) -

( 2 ) - jeff. Appliance Repair Aid

[Jim Rusling]

In addition to what the others have said, I have one that I bought when the main air conditioner went out and also use it off the generator when power is out. They work and you can move them from room to room. They just take a few minutes to set up. The ability to easily move them is the only reason I bought this kind instead of a window unit. Windows units do a better job and are cheaper, that given I would buy another one when mine quits.

[nicksanspam]

Sounds like you are confused.

Nick

[User Example]

They do work. I have one and the air coming out is very cold. The only problem with them is that they suck air in from outside to replace the air the blow out the vent through the window. Very inefficient.

The condensation either goes to a bucket, out a tube, or is evaporated out the exhaust depending on type of unit you have.

These things are good if you can't use a normal window unit due to no window or you dont want it sticking out the side of your house.

[Tom]

The air coming in, is the same air going out after it has removed the heat from the coils. Room air is not removed, nor is outside air introduced to the room. I do see some inefficiency because of the fact there is some restriction to air flow while doing this. In a window unit, the heat is immediately dumped to the outside and doesn't have to be fan forced up and out a tube.

Tom.

[Dr. Hardcrab]

No. He's right on the money....

[User Example]

Not true. They blow air out two places.

1. Evaporator air: Out the front vent (cold air).
2. Condensor air: Out the hose that goes out the window. (hot air)

Air for both #1 and #2 come from the air in the room. But if #2 is blowing air OUT of the room that means that: a. The room will eventually be sucked dry of air or b. Air is coming into the room from somewhere else.

Unless a magician is creating air in the room then it has to be drawn in from some other room, cracks in the walls or ceiling or somewhere else.

[User Example]

Yea, I have seen those 2 hose things. I tried to convert my one hose type to a two hose type with some cardboard and duct tape. It sort of worked but it fell apart and then I just bought a mini-split.

[Paul]

I bought a DeLonghi unit 4-5 years ago (approx $800 at the time!) and am pretty disappointed by it. It is wimpy, doesn't cool as well as a much cheaper (and lower BTU) window unit. Cycles constantly. Thermostat has a hair-trigger response, either "always on" or "not on enough". Noise level higher than a window unit even though it is advertised as "whisper quiet". Fit and finish poor (front door rattles, compressor vibration noise) Would not want to sleep in a room next to this thing.

-- Paul

[Stretch]

No, Nick is right. (me agreeing with Nick..... scarry!) Outside air is brought into the house, bringing heat and humidity with it. That air mixes with room air, warming and humidifying the house. Then it is drawn into the spot cooler and exhausted through a duct to the outside. So the portable unit acts like an exhaust fan.

The net effect is you get very little real cooling and increase your electric bill. If you can find one with a ducted outside air intake as well as a ducted exhoust, it would be much more effective.

With spot coolers, you would do as well to stand in front of a residential refrigerator and open the refrigerator door to get cool!

Stretch

[Goedjn]

The thing is obviously going to be less efficient than a system that keeps inside air inside, but:

If a quantity of air Q1 comes into the room and is separated into to other quantities, a hot, wet Q2, and a cold, dry Q3, and Q2 is exhausted outside, then the air inside Q4) will obviously be cooler and dryer than Q1. (but warmer and wetter than Q3).

If you assume the worst-case, that Q1 mixes thoroughly with Q4 before being sucked into the unit, then you should *eventually* reach equilibrium at q4=(q1+q3)/2. If you get the best case, where ALL Q1 goes through the unit before mixing, then you reach equilibrium at q3.

--Goedjn