Home>Discussions>INSULATION & HVAC>Odd window unit question: (oversized in the desert)
10 posts / 0 new
Last post
Someguy191
Odd window unit question: (oversized in the desert)
Someguy191

Hey all, very odd question. Usually you do not want an oversized a/c unit as it cools the room too quickly and fails to remove the humidity from the room (it ain't the heat, it's the humidity!). However, I live in the high desert where it can reach the mid 100s in the summer with <12% RH (it ain't the humidity, it's the blast furnace!). For example, in the next 24 hours the temp range is supposed to be 59-95 with a corresponding humidity range of 43-12% So I actually want as much humidity left in the room as possible. So I was thinking of replacing an aging 5k btu unit (takes more than 1 hours to chill the room fully from ~90 to ~74) with a new (11.x eer) 8k btu unit (it's cheaper than the same brand's 6k unit by nearly $50 and I already have one of the 10.x eer versions and like it in a somewhat larger room).

Am I missing an obvious reason that a 6k unit is a better fit? To me, the $50 savings and being able to use it as a backup for the other unit / in a larger room seems to suggest I'd be silly not to buy the 8k one as since I live in a place where it is never hot AND humid unlike pretty much the rest of the country I would have to add the humidity back into the room to keep the RH in the comfortable range...

Thanks!

dj1
Re: Odd window unit question: (oversized in the desert)
dj1

5K BTU is for small rooms (up to 150 sf).
6K is for slightly larger rooms.

You know your bedroom size, so just match the unit with the size. The price you pay is not a reflection of the quality, size or BTU, you may pay less for a 6K unit, because the store has a special.

Someguy191
Re: Odd window unit question: (oversized in the desert)
Someguy191
dj1 wrote:

5K BTU is for small rooms (up to 150 sf).
6K is for slightly larger rooms.

You know your bedroom size, so just match the unit with the size. The price you pay is not a reflection of the quality, size or BTU, you may pay less for a 6K unit, because the store has a special.

It seems like you didn't actually *READ* the post I made. Or at least you didn't read most of it, so I'll try again to explain my question a different way, sorry if this sounds terse but if you're going to post an answer it's somewhat useful to actually read the whole question, not just see that it's about air so go with canned response #421 under the assumption that someone doesn't know how to properly size AC units. Again, please try to read this, I know it's hard but if you don't have an answer for the main question DON'T REPLY, it just agitates the OP and causes them to possibly write annoyed posts ;)

First point (in response to your post):

the 8k unit is $50 cheaper than the 6k unit and is the *same* manufacturer. As I said, I have another of the 8k units from the previous year, it's a good (quiet!) unit, that unit is in a room that would be served in the rest of the country by a 6k unit but is quite comfortably served by an 8k unit.My question was not about quality (I know the quality), it was not about price as the fact is not that it MIGHT be $50 cheaper, it actually is. (this isn't schroders cat, I know the results as the box is open ;) )

Second (now pay attention and please READ THIS as it has the actual question that I asked and you failed to read/comprehend) point that is the whole reason I posted here:

My main question is about RH (relative humidity) in that where I live there aint any (look above for actual numbers, but during the summer while it's hot RH is < 20% and frequently <14%). I really don't want the a/c unit to reduce the in room humidity (at ALL ideally) as whatever humidity it removes from the room must be re-added to prevent excessive static electricity, keep lips/skin from drying out, and get rid of the occasional nose bleed. So the whole, bigger is worse because it "short cycles" (cold and clammy for the rest of you people with water in the air, since an accurately sized a/c unit both provides cold air and reduces the humidity) is actually a prospective selling point as I won't have to run a humidifier in the room to keep the RH livable. So my question was, aside from a lack of reduction in humidity (again, that's a selling point when you live in the DESERT), is there any reason to not opt for the overkill that an 8k btu unit would provide? There's a chance that it might not last as long though likely it will still last 5+ years by which point a/c units will be even better, and I may have taken the jump to ductless minisplits or something of that nature)

Thanks to anyone who can actually help with the RH and oversized AC question. I can actually add, multiply, and even divide so I know what size unit I'd want in a traditional situation (say if I were back in the midwest), but living in the desert isn't traditional.

ed21
Re: Odd window unit question: (oversized in the desert)
ed21

Snarkiness aside, I believe you are overthinking the situation. Buy the cheaper, larger unit and see how it works. It's been a while since I had a window unit, but don't they have low settings?

dj1
Re: Odd window unit question: (oversized in the desert)
dj1

Here is your question, and I quote: "So my question was, aside from a lack of reduction in humidity (again, that's a selling point when you live in the DESERT), is there any reason to not opt for the overkill that an 8k btu unit would provide? "

Here is my answer: No.

You want to keep your RH? don't use a/c.

You want to raise your RH? use a humidifier.

You want to cool your room? use a/c.

You want to buy an 8K unit? buy it.

You want to buy a 6K? unit? buy it.

Don't like living in the high desert? Move to the low desert.

Someguy191
Re: Odd window unit question: (oversized in the desert)
Someguy191

Awesome thanks guys! Sorry for the snark, but it was a fairly straightforward question (if really unusual) my mood was compiled by the inability to log onto the forum as apparently someone from a canadian proxy server was trying to hack into my account so that every time I tried to log in, I'd get the error that I'd attempted to log in too many times and to wait 15 minutes (in fairness who can blame the hackers random TOH accounts are surely worth their weight in ****)

(yes, I know I can add a humidifier, but if the properly sized a/c unit will spend some portion of the time removing the moisture I'm attempting to add to the room that's less than ideal and in theory is a waste of electricity as well as of water.)

Mastercarpentry
Re: Odd window unit question: (oversized in the desert)
Mastercarpentry

The 1 hour cooling time if the old unit shows that it's insufficient for that use so you do need a larger unit. That will likely add some dehumidification as you suggest but that cannot be helped- it;'s inherent in the process. Since you want both things you may have to add a humidifier along with this and accept the extra cost as part of living where you do.

Or you can alter your expectations because no amount of money or effort can change the laws of physics and this is just how AC systems work. You can't always get what you want, but if you get most of it you're doing pretty well.

Phil

ed21
Re: Odd window unit question: (oversized in the desert)
ed21

Anytime you can reduce the temp from the mid 100's(is that really 150 degrees or like 105?:)) any cooling is a good thing.

dj1
Re: Odd window unit question: (oversized in the desert)
dj1

Ed, right now, my attic is close to 120 F - and I'm not in the high desert. Inside temp is mid 80s (good insulation), and will reach 93-94 later, between 6pm-7pm. We only run the a/c on prolonged heat waves, usually in July-August-September...

150 F in the high desert (Palmdale, Death Valley) does happen. There is a town on the way to Vegas, called Baker, which is known for the world tallest thermometer - actually it should be called "the world's tallest thermometer showing the highest temp".

ed21
Re: Odd window unit question: (oversized in the desert)
ed21

I thought it was just the outside temp. I haven't measured my attic, but it gets pretty hot on a sunny day. Not as hot after the ridge vent was put in. Amazing how well it works.
Today was in the upper 80s, but it's so humid the sweat soaked me after an hour outside doing easy word work.
I doubt that compares to 110 with no humidity though.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.