Quick Window Mount AC Question

[mikester]

My sons renting a 3br ranch and he needs a window mount AC for a bedroom. The room is 10x13 with an 8' ceiling. He bought an 8K BTU but I think its a little large for the room. I think he should use a 6K instead. He wanted one hooked to wifi so he cold turn it on from work. What do you guys think ? 6K too small or 8K too large ?

 

[American Locomotive]

8K seems really big for that size room. It'll likely short-cycle, which won't be terribly efficient. I'd think a 5k would do just fine in that space.

Granted, it also depends on where this house is? Is it in Phoenix Arizona, or Nova Scotia? That'll make a difference.

 

[Sneezer]

I used a 10k BTU portable unit, single hose type, for one bedroom when our main unit crapped out one year. We live in TX, and it was able to keep the room at around 72-74, but not really any lower during the day. This was unimproved 1970s construction. Given how inefficient those portable ones are I would think an 8k window unit would be the max. Granted, we also keep the house around 68 during the summer. I don't think a wimpy 5k would keep us happy.

 

[American Locomotive]

You absolutely cannot compare portable air conditioners and window air conditioners. The single hose type portable air conditioners are absolutely terrible. On really hot days, they can actually make a room hotter. Every bit of hot air the portable AC blows out the hose, needs to get replaced. In that case, that means hot outside air gets pulled into the house.

Window ACs completely separate the hot/cold sides. The hot side only draws outside air to do its thing.

 

[mikester]

House has been totally updated. New windows, plenty of insulation. I was surprised that it doesnt have central AC but its got a 2 year old boiler. House is on Long Island NY. We have some humidity and hot days during the summer but its not like we're in FL. I think 5K would be on the small side but I was concerned the larger unit would short cycle and keep the room a little damp.

 

[Bert_]

5000 would be more than enough. It's only 130sq/ft.

I cool the 1000sq/ft main floor of my house with an 18,000 btu window ac. It's about the right size, could maybe do it with a 12000 most days. Two rooms have good insulation and are air sealed pretty well, rest is all 1920's except some blow in fiberglass in the walls from the 70's.

Can't imagine NY gets any hotter than Iowa.

 

[787B]

I've been cooling my ~1000 sq-ft house with three window A/Cs totaling 16k BTU for the last 15 years. Biggest is 6000 BTU for the main living area. Other two are 5k; one each in 145 sq-ft bedroom and "office". More than enough even on days when temps and humidity are both high 90's. It gets hot and humid here in July-August.

For a 130 sq-ft room, 8k is way too much, especially with updated windows and insulation. I think it will short cycle and - worse - not remove the humidity because of the short run time. The room will be cold and clammy.

The remote control is nice, but overrated. Automation is better. I use LUX WIN100 5/2 programmable line-voltage thermostats to run my A/C's on a schedule. They are about $30 and work like a charm. I also use them in the Winter for space heaters, and I use one in my garagement/barage to shut off a dehumifier below 60°.

They also work better than even the fancy window A/C thermostats because they have some separation from the window units.

 

[787B]

I used a 10k BTU portable unit, single hose type [...]
I don't think a wimpy 5k would keep us happy.

I think you would be surprised how well a 5k window unit would perform in comparison to that single-hose portable. Probably better. And half the cost.

This guy makes some great videos. he has one on portable A/Cs:

 

[metlmunchr]

I remember years ago those single hose units were marketed as spot coolers for use in plants where you'd have a person tending a machine in an area that was hot as hell, so you'd buy the cooler to blow cool air on the employee to make the job bearable. That the condenser air was pulled from the space and blown out a few feet away was immaterial, as the only purpose of the unit was to create a cooler spot for the worker to stand or sit in. For that use, they worked okay albeit extremely inefficiently.

Over time, more and more businesses figured out that air conditioning their plants not only made it easier to hire and keep help, but also made those employees more productive. As the market for spot coolers shrunk, marketers reinvented them as portable air conditioners to sell to anyone who didn't understand the fact that sucking air out of a room to blow it thru a condenser and out a window only results in an equal amount of hot humid air being sucked into the house thru any and all available openings.