Portable A/C’s & B.T.U. vs ASHRAE

[NiceGuyEddie]

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https://www.lg.com/us/air-conditioners/lg-LP1014WNR-portable-air-conditioner

1,200 square foot 4-level New York City style loft, mostly brick & mortar, 11’ ceilings. Top level living room is about 300 square feet. We have Pacific Ocean breezes but it still sometimes get hot enough to want A/C. I somehow acquired the above older portable A/C for free so I tried it. With this little guy CRANKED it keeps the living room to no more than 80° during a +100° heatwave. Good enough for free. The lower levels of the loft don’t get as hot. The a/c pulls out a lot of water so that’s a good thing.

I’m willing to buy a slightly bigger portable a/c if it works better and if it’s a bit quieter. Problem is, I don’t know what I’m getting into. I read that the ASRAE standards are “more accurate” but the marketing of these portable units are all over the place.

This one says, “7,800 DOE BTUs / 14,000 ASHRAE BTUs” and cools up to 700 square feet.

https://www.amazon.com/FRIGIDAIRE-FFPH1422U1Portable-Rooms-700-Sq-Conditioner/dp/B077VFGTKM/ref=sr_1_18?dchild=1&keywords=portable+a%2Fc&qid=1614985669&refinements=p_n_feature_three_browse-bin%3A14554138011&rnid=14554131011&s=home-garden&sr=1-18


Another unit says "8,500 BTU / 14,000 BTU ASHRAE", why aren't the numbers the same as the Frigidaire?

The numbers don’t make sense to me. Can’t seem to find any helpful online charts. Any attempts to confuse me more are greatly appreciated! :D

[JimLev]

Any reason you can’t go with a split air system? The compressor is outside and feeds 4 wall mounted units inside that are very quiet. The garage has it’s own split air system. They all do cooling and heat.
Mine are made by Carrier.
https://www.carrier.com/residential/en/us/products/ductless-systems/

[NiceGuyEddie]

Sorry to say it's a 100 year old building and the unit is on levels 5 thru 6. There are a few units in the building that have a/c with compressors on the rooftop but our place isn't anywhere near a place to mount a compressor.

I found a window a/c that is low-profile and looks like a ductless, but it's 240V. A traditional window a/c won't work because the bottom window is a push-out and doesn't open very far.

[Kay_B]

Maybe some of the air conditioners that are in this review https://homemakerguide.com/best-smallest-air-conditioner/ will suit you? There are different options here, to my taste, which are installed under the window. It will not interfere, and does not require the installation of a compressor.

[NiceGuyEddie]

That's a good comparison page. I've seen loads of videos on YouTube that say "Best Portable Air Conditioners 2021" but them seem to be random compilations of new products and not necessarily something that somebody tested.

Portable A/C's are definitely ugly - that's part of the story. I plan to make a wooden case with a cover/door for it, put it up a little high and route the water tube directly outside. I also plan to carefully cut window Lexan so the exhaust tube goes directly to it and not to the "adjustable" plates it comes with. The window above pushes out, hinged at the top, so it's not like I can simply put the exhaust tube adapter horizontally and close the window on top of it.

Example attached, it looks like one of the neighbors did a good job with a "basement" fan.145088

[RBachman]

I'm a bit late to this, but can offer an engineer's perspective...hopefully without getting too deep in the weeds. So I'm a tad loose with the terms and comparisons I use here.

The DOE figure reflects the net cooling capacity less parasitic loads. The ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) figure more-so represents the rated equipment capacity under certain design parameters and atmospheric conditions. It's more of an equipment rating, not conditioned space performance. The DOE figure is there to help compare the net useful capability by accounting for the heat that portable units dump back into the same space they are conditioning, i.e. parasitic loads. Much of which is just from the outdoor intake and exhaust ducts. The DOE figure reflects this. For example, ASHRAE 12,000 BTU and DOE 8,500 BTU roughly means that: (12,000-8,500)BTU = 3,500 BTU getting dumped back into the room. So go with the highest DOE number relative to the ASHRAE number. For these small systems the DOE comparison is a good snapshot of what to expect.

With all that said, a couple things to consider:

-Manufacturers tend to be overly optimistic in their performance claims. They are also optimistic on cost of operation.

-Condenser coil size matters. Bigger is always better to a degree, but it also means a bigger box and increased cost. Bigger coils make the system more efficient because they have a larger surface area to transfer more heat out of the conditioned space.

-Energy efficiency is good and bad. Consider the bump in equipment cost verses the savings in energy cost. Generally, the mid level efficiency systems are where you want to start. If you get the most advanced efficient system available it won't provide enough savings to cover the added cost. Additionally, more advanced systems often tend to be more complex and less reliable.

-Buy from a place you can easily return it. If it fails to perform as claimed, take it back.

-Insulate the ductwork and plastic window insert, or buy a system that has this included. Otherwise there's a hot discharge duct radiating heat right back into the space.

Hope this helps.

RB

[NiceGuyEddie]

-Insulate the ductwork and plastic window insert, or buy a system that has this included. Otherwise there's a hot discharge duct radiating heat right back into the space.

RB

I NEVER considered this. The exhaust tube gets really, really warm to the touch- that's a good thing because it's dumping the air but the tube itself is a bit of a heater! I think I'll wrap it in header wrap.

[NiceGuyEddie]

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I went with the Delonghi unit because it was the most expensive. It weighs a whopping 85lbs so hopefully that means a uge compressor. For the window, I cut my own hole in a sheet of Lexan and it works perfectly.

The good news is it's incredibly quiet. There is a whisper mode to make it even more quiet - no idea what it's doing. The attachment from the tube to the a/c is better than one's I've had before - it detaches very easily so you can wheel the unit away and drain the water when you need to. It hasn't been particularly hot lately so I can't speak to the overall cooling performance but it seems promising.

The only thing I don't like is the fan speed - with the older one I'd turn it towards the staircase at night time to help shoot cool air down to the bedroom area. But hopefully the cool air will find its way downstairs anyway.

[NiceGuyEddie]

UPDATE - just for kicks. The De'Longhi PACEX390BK 14000 BTU (pic in post above) unit has been great! The lowest setting is 67° and we just keep it at that so it keeps working. (It's not on 24/7.) I don't know the temperature in the room, but it's comfortable.

It's like a big block engine - seems like it's hardly working, but it works better than the small older one I had.

Two strange things:

1. The exhaust tube isn't as warm as it was with the old one. There would be little or no benefit to that insulating sock that was suggested. You'd think that would mean less heat transfer to the outside the window, but there isn't. If anything, there's more. (The Diameter of the tube is the same.)

2. It's been almost 3 months and not once did I drain the water from the bottom. The unit is supposed to self-evaporate, but with the smaller one that screamed at a proverbial 8,500 rpm I had to drain it every day. I originally planned to put this thing on some sort of stand so a water tube could drain right out the window, but it turns out it's not necessary.