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Small A/C Unit on Back Porch

I have a small back porch that is approximately 110 square feet. The entire back porch in enclosed. The porch walls are as follows: 2 walls are exterior walls of the house, one wall is the exterior wall of the garage, and the fourth is a sliding glass door.

I want to put a small A/C wall unit on the porch. The problem is that the sliding glass door takes up the entire outer wall of the porch. There is no place to install a unit without replacing the door with a regular 32' or 36' door. I don't want to do this.

Is a portable air conditioner my only alternative? I could route the exhaust through the garage wall and then to the outside. But, I would prefer a wall unit. Any ideas?

Re: Small A/C Unit on Back Porch

If you have central air in the house you could install a vent from the house unit with a zone damper (6 inch dia) .110 sq feet should not cause to much affect the house system.You would have to cut a hole for the portable unit any way.

Re: Small A/C Unit on Back Porch

There are many products today that are designed for just such an application. Depending on the elevation of the porch, you may be able to feed the space from overhead or underneath. You did not indicate what if any attic space is overhead or crawlspace below. Be very, very careful about a zoning application to this space as most systems require no less than 25% of the total airflow within the system to be dedicated to an independent zone. If you ran one (1) 6" lead with a zoning damper to this area, and this was the only area that was calling for air, then the system would encounter problems.

Could you run a 6" lead from the existing system without adverse effect on the system? Probably. Would it provide you adequate heating and cooling to the space? Maybe. :rolleyes:

I, myself would much rather resolve the problem intentionally, instead of accidentally. ;)

It is (imho) a mis-application to use a "portable" air conditioning unit for your porch. Portable units are designed for temporary use, and I am concerned when I see this recommended as a permanent solution. It is not.:(

There are ductless systems that would enable you to mount a small fan coil unit on the garage wall and with a small opening route the lines, drain, etc. to a small outdoor unit. This would provide you with totally independent cooling (and heating) of this space.

You only mentioned a/c but, if it was me, I would be more interested in making this as much of a year-round space as possible. Now is the time to do so.

Have a professional HVAC contractor come in and perform a survey of the space and get his / their recommendations.

All the best, Irishmist

Re: Small A/C Unit on Back Porch

Yeah, like I said....................:D

Re: Small A/C Unit on Back Porch

Thanks for all the input. I will consider adding a new vent or using the mini split system.

Re: Small A/C Unit on Back Porch

Irish got it 100%.
Adding a duct will only waste your money, most likely.
Having a room with a heat load completely different than the hall where your T-stat is located will yield dissapointing results. And he is also correct about zoning, when your little porch is the only zone calling, you must still dump that air somewhere, you dont want your whole house comfort dictated by your closed in porch.....small ductless mini-split, no more space than your talking about should be pretty cheap, and alot quieter than having a compressor 3 feet away, in the room basically, while your trying to relax.
Quality of life is the whole reason for this space, is it not?
Call a Contractor and install a little mini-split heat pump, it will be quiet, and comfortable ......which is what you want, right?

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