Venting a Portable Air Conditioner

It can be, but it's never a good idea. You will be pumping moist air into the attic and stale air from the attic.

Not to mention the fact that the attic is already the hottest space in the house, and that's where you'd be humping the heat to. Agreed, a very Bad Idea.

If you vent to the attic you will need to install an exhaust fan in the attic or a roof ventilator on the roof. Figure 500 to 600 cfm fan per ton of A/C capacity. It will be a bit of work and expense...why not simply vent to the outside?

Yes, I will vent through a wall and the attic into the soffit.

Thanks for the reply.

I thought that since the unit wouldn't be used that often, and the attic space is well ventilated, it wouldn't cause too much moisture to collect.

I think I will vent the A/C through the attic space via a hose and go through the soffit.

Thanks for the reply.

Also, what are you going to do with the condensate?

Thanks for your reply. There is a pan to catch the condensate from the unit.

The vent of a portable AC, when a big hose, is the INTAKE not the vent.

The vent is your room and the condensation is the water pan.

(some however have a reverse system to get rid of the moisture through that hose too)

The attic is mostly a hotter area, so your AC will have to work harder and will not perform well.

You better use it also in recirculation mode to get the air inside the room also drier.

This depends upon what kind of cooling device we are discussing. Is it an evaporative cooler or a refrigeration air conditioner?

In the case of a refrigeration type air conditioner, heat is pumped from one side of the device, the cold side, to the hot side. That heat must then be carried away, thus necessitating a hot air vent to the outside, though some non-portable systems do use cold water to carry away the heat. And the only place you have condensate is on the cold side, which also makes this type of cooler an effective de-humidifier.

An evaporative cooler on the other hand, often referred to as a swamp cooler, cools the air by using ambient heat to evaporate water, thus adding humidity. Perhaps obviously, these types of coolers don't work very well in humid climates, and to continue to function efficiently, do require a continuous supply of dry air, which necessitates removing the humid air as it warms.

So, the question is, are we talking about a swamp cooler or an A/C?

This explanation is complete and correct. GA

Thank you sir.

No, I wouldn't use the portable a/c in the attic, but in a room next to a part of the attic. I will vent through the wall and the attic space via a hose and then through the soffit.

Thanks for the reply.

It should only be considered if the attic itself is well vented either by power or by ridge vents with inlets at the eaves soffit.

The attic is well ventilated, but I guess I'll go ahead and go through the wall into the attic space and then go out through the soffit.

Thanks for the reply.

Not a good idea unless the attic is very well ventilated, cool and dry.

Could the attic warm air be used by the AC in the heat mode, during winter?

When your attic is the warmest place in the summer, it could be the coldest place in the winter? It tells certainly something about the insulation. (isolation)

It is not generally not recommended as it increases the load on system and air- conditioner performance will reduce . Sometimes air conditioner will fail due to poor condensation. You can check up with the manufactures instructions for specific detail on this.

Thanks for the reply

YES

I did this once in a commercial kitchen with 1 Ton 'Spot Coolers'. It was the quickest, cheapest temporary solution. I encouraged them to buy 'ductless split systems' but it wasn't in their budget.

I can't understand why ductless split systems were not available twenty years ago, unless it was because contractors wouldn't sell them and government inspectors frowned - no ducts, less installation costs. I will tell you that one of the Asian customers I serve has said he has seen them everywhere back home for years.

Say "Thank you, Mr. Building Official, you have protected your contractors at the expense of the public again"

Spot coolers discharge "heated up" ambient air out a flexible duct - it is the same relative humidity as the room air where the machine sits. Only the dry bulb temperature changes as the air passes through the machines condenser.

In this case the 6" flexible duct condenser discharge was run up above the suspended ceiling. Yes of course, I am sure the condenser fan sets up a circulatory system exchanging air from the occupied space to the volume above the suspended ceiling - eventually exchanging air from the occupied space with air pulled down from the volume above the suspended ceiling.

However, the volume up there is frequently 50% or more of the occupied volume, so I think there is sufficient capacity to discharge warm air.

As another comment wisely pointed out, there should be no problem in a well vented attic space. I agree and give a GA.

Silly question, I know, but do you want it to rain in yer loft, mate? <Splutter, cough, sheeze>

That's how I got ill! <Cough>

You can vent it to outside or attic.

No. -- JHF

How efficiently and how well a regular window type air conditioner works is directly related to how cool the outside coils are kept.

If the outside coils are in direct sunlight, or up in a hot attic the air conditioner may not seem to function very well, and will work way harder to produce the same amount of cooling.

If the outside coils are kept in the shade the unit will work better, and if you spray a mist of water over them your air conditioner will run much cooler and much better. You can also put a coil of copper tubing around them,running cold ground temp water to heat water to increase the efficiency.

I believe you can heat a room with them by simply turning them around in the window in the winter and moving the compressor thermosensor inside the building.

There are also 2 way window heat/ac's on the market, that do heat and cool without turning the unit around.

Capture the condensation and use it to flush toilets or water plants or somthing. No sense discarding free water these days.

I always wondered as well why split units werent used in homes. I would love to get someone to take a car air conditioning unit and hook it up in a house or fridge for me. That way, all i had to do was figure out a cheap way to spin a flywheel,hook up a pully belt and let that turn the a/c compressor cooling the house.

The unit would be in the room and not exposed to the elements.