I am a chemical engineer, and have worked with both the theory and practical aspects of AC.so let me give you a brief rundown of how to ick te best unit for you, and how to get the best performsnce afterward:
1. Picking a unit: (use the sortable list on to compare different models)
a. There are two main types: 3-in-1 and 4-in-1.
3-in-1 modes are Fan, AC and Dehumidifier. The dehumidifier mode uses the AC to cool the air until the water comes out, then puts the hot ir it sends outside when working as an AC unit back into the room instead of sending it outside.
4-in-1 adds a heater. Cheap designs use an electric heater coil placed in front of the fan. (Ok if you only want a little heat, now and then, or if you want heat when it is colder than 41 degrees outside. (buy this in Maine.)
More expensive 4-in-1 units do not use an electric heater, but act like a "heat pump"that is, they work like good home units popular south of the mason dixon line (wiki it, kids). More about this when we get to my FAQs on mode 4.
Mode 1 FAQ
While buying an AC just for the fan is not smart, don't underestmate the fan only control. Moving air over you can add 5 to 6 degrees to the temprature you feel is comfortable. If it is only 76 or 77 degrees out, try just sing the fan, and pointing it at you. It will usually o the job unless the humidity is extremely high.
Mode 2 FAQ:
AC size is measure in BTU but typically you need 6000 BTU for a room that is 200 sq ft (eg, it is 20x10 or 14x15).
This is if the room is well insulated, the sunlight does not stream in, and the AC is left on so you don't need a quick cool-down. people by an 8000BTU unit and expect it to cool the hot, hunid 350 sq fot bedroom in 1/2 hour. The web site I recommended has tips on correct sizing. One tip I will add is that the exhaust hose is 15 inches fully collapsed. The more you extend it nd make it go around bends, the poorer it will work. Lots of sharp bends and fully extending the hose will "derate" the effective size (and efficnecy) by possibly as much as 20%. When in doubt, buy biggerbut too big a unit will make a gale when the fan is on, and will cycle on and off way to often.
Mode 4. (yeah, its out of order, but this is for a good reaon).
Heat pumps reverse some valves in the AC unit, and suddenly, the pipe going outside gives off cold air, and the indoor part puts out hot air, This is roughly twice as energy efficient as the cheaper heating coil, but stops working around 40 degrees of outdoor temperature.
Mode 3 FAQ: Dehumidification only, and, oh yeah, an AC does dehumidification while it cools-
Actually , the AC dehumidifies too. If the basement is too damp, you can use a portable unit to warm it up a little and dry it out a lot. Then, if it gets too warm, switch to AC and cool it and dry it. For htat matter, just sit a windo unit on a chair, and let it blow back into the room instead of out a window, and use it as a dehumidifier.
In coastal regions, and near rivers and lakes, the air is very humid. Dehumidifiers must cool the air as much as an AC to get rid of the water, (and use as much energy as an AC does), but they dump the hot air back into the room instead of pushing it outside. unless you have a cool damp basement problem, the Dehumidifier only mode is not the answer.
But what happens to the water from the dehumidifier action? An AC may use more energy removing the water than cooling the air. (this is why it tale so long to cool a hot, humid room the first time, but if it is keep closed, so that the next day it is only hot, it will not take nearly as long to cool it down again.) A room sized machine will typically remove 10 gallons (40 pints) or more a day. The water runs to the bottom of the unit. Window units drain the water that collects in the bottom of the unit out the window. A portable AC has to collect it. Typical collection resevoirs hold less than 4 pints, at which time a float switch stops the cooling and leaves only the fan (so you think it doesn't cool after just a few hours use if you just plug it in and let it run.) You can attach a hose and drain continuously (use a hose clamp if you do), or else empty the tiny resivoir each time the AC stops cooling. The trouble with using a hose is that the hose is not very high off the floor, and the resevoir will simply overflow if you don't notice it is full.
Here is my solution. Elevate the machine a few inches by standing it on a set of bed leg height adjusters (>$10 at a hardware store), then, attach the hose, and fashion a hook to hang the end of the free end of the hose up on the machine. I straightened a large paper clip and tied it around the hose near the free end, and bent the end of the paper clip so that it hooked into a convenient spot high enough up on the machine to know the hose would not overflow before the float inside the machine shut off the AC. Since the hose is transparent, I can see how full the resevior is, and, without shutting off the AC, unhook the hose and drain it into a 1 gal plastic jug that sits on the floor and has a hole in the side near the top. Hang the hose back up on its hook, and use the water on your plants or in your iron. (it is actually rain water that you made yourself).
The reason, by the way, they can remove 40 or more pints a day, and only have a resevoir 1/10th the size, is that they blow most of the water they collect onto the condensor coils (the ones that put hot air back outside). This water helps cool the coils and makes the AC run more efficientlyand you don't have to dump it. (They do this to help get back the energy required to remove it from the air that is going into your room.)
About 90% of the water collected will be used this way. This means that if you have no humidity, your energy bill will be about the same, since you don't take it out, and don't put it back. However, if you do live in low humidity, maybe you should be buying a much cheaper evaporative cooler, that cools you by spraying water into the air.
If I can go back to mode 4 (heater, again, It also means that the manufacturer of units with a heat pump mean it when they say that when you use a unit to heat with, set up a continuous drain. Spraying the water on the normally hot (now cold) side will form ice, and freeze up the unit, causing it to fail to operate, and possible damage to the compressor.
For the advanced student, who wants to continuously drain the unit in the summer, Just remember that you are eliminating one of the big energy reducing featurethe re-use of the water to spray cool the hot condensor coils. My hose trick can be modified by putting a tee connector in the hose above the drain outlet of the unit, but below the height that causes the compressor to shut offconnect an overflow hose, and any water that is needed for the cooling of the coils will be available, but the exces will be available to safely drain away. hopefully, you are now hagh enough to draininto a 5 gallon plastic gas can, or something, but you have to know what you will do with all that water. They sell plug in drain pumps that can be used to keep your overflow can emptied out, and that can pump the water through a small plastic tube wherever you want it.
Have a whole house AC and don't need more? read this:
My house is in Floridatypical daytime temp of 94, with 65% or more humidity, and while night time temps go down to 70 by about 3 AM, the humidity goes up. No one lived in Florida by choice until the invention of AC. My reason for buying the portable units was to create a "zone" in my bedroom at night, (set the Hose AC at 80), and also to have small unit that I could put in my TV room in the cold months to use between 7 and 11 in the evening when we like to watch tV (let the whole house cool, and sleep under blankets in the now cool bedroom when we go to bed.)
For this reason, I got a 4-in-1, and because I live below the mason dixon line, I got a heat pump version.
I hope this review prevents you from experiencing any of the reasons why so many people had bad experiences with the same products others found to work well.
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I live in Pittsburgh and we do get some heat here in the summer. Small apartment in a 60 year solidly built building. I have been running this machine during the day for over 2 weeks now and I love it. I am not a big fan of really cold air-conditioning and so far this unit does not make my place a freezer, but makes it extremely comfortable considering the shape of my apartment, i am cooling about 630 sq ft with bedroom and bathroom doors closed. So it is a little over its recommended cooling area, but for my needs, it is more than great.Now, one thing about draining the water out of the unit.....I haven't. Was delivered on July 6th and as I said above, it has been on all day since then. I hardly run it at night as once my place is in my comfort zone, it stays that way all night. I have not had to empty any water and it has been humid here. I am almost frightened to say anything about that in front of it so I don't jinx myself.
I did buy the Square Deal warranty for this for three years so that if it does break down, I am covered. Anyone who does not shell out the money for that at the reduced rate you get from Amazon is being quite foolish with their money. Way cheaper that what you would get at Best Buy or Sears by more than 50%.
In the winter, I plan on rolling it into my bedroom to heat that area. We still have radiator steam heat here and during temperature transitional days, temp goes up then down real fast, the heat does not catch up for about 24 hours. This will make that room much cozier.
