Economics of running a small window AC unit

[The_Eric]

Hey all, I'd like your input on running a small window air - we have central air, but the issue is that at night the better half likes it cold to sleep. I swear we could hang meat in the place at night It's usually around 64 degrees.. Well, I go to bed later than her, so I'm bundled up in sweats, a fleece jacket and socks.. in the middle of the summer for crying out loud! 75 to 78 would be far more comfortable. Not to mention cooling the entire house surely can't be that cost effective? I realize that central air is typically more efficient, but this is a pretty old system at 25+ years old.

Are modern window units efficient enough that we would see a savings? To clarify, no, the house is not 64 all day, just after 8:00 pm. It is set to go to 80 when we are away, then 78 at 1:00 when she gets home. Also, how quiet are window units? Are there some that are noted for that? She is a bit of a princess when it comes to sleep - has to be quiet and DARK.

As always, thanks in advance for your input!

 

[PimTac]

I don’t see how it could hurt. Get an inverter unit for the better energy efficiency.

 

[Taildragger]

Put a mini-split in the bedroom for the win!!!

 

[John105]

Put a mini-split in the bedroom for the win!!!

Yes!

I really can’t speak from experience as we have central air. I would think that a window unit isn’t efficient and isn’t quiet, going back to my apartment days. For a permanent solution, a mini split would seem to make sense….and I hear they are more efficient than central AC

 

[supton]

Wife refuses to go with mini-split, says it looks like a hotel. *sigh* At least in NH our a/c season is only really bad for 3 months or so. Not about to do central air too soon (maybe after I win the lotto that I don't play).

My wife is odd (but whose wife isn't?). She likes to bundle up--cold room so she can pull out the blankets. I like it cool too but for me a fan goes a really long ways.

 

[zfasts03]

Window units are very energy efficient, but are not known to be quiet. I would be researching reviews for the units that are the quietest as this will be the biggest challenge.

 

[eljefino]

My 5000 BTU window unit draws around 450 watts. It's loud, but in a white noise kind of way.

My Mr Cool heat pump is way more efficient, but it's downstairs, and its coolness ends in the stairwell.

 

[DemoFly]

Yes if you can't cool the bedroom as a specific zone, a window unit is cheaper by a ton.

Consider a mini-split in the future. Lots of govt incentives atm. Educate her on how much less they cost to run than a gaudy, loud, window shaker.

 

[atikovi]

Imagine if she could tolerate having your washing machine in the bedroom going all night. That's about how loud they are.

 

[UG_Passat]

the window AC units aren't horrendously loud as some of you make it out to be.

I assume some people here grew up or owned a house that didn't have central AC before.

It's only around 41 dB, which isn't that loud or annoying. And you can by units making 40 decibels or less, but they cost a lot more money

 

[umungus1122]

Yep, just run the small unit in the bed room at night. Then you can turn down or off the central AC in the rest of the house at night.

 

[ctechbob]

Yep, just run the small unit in the bed room at night. Then you can turn down or off the central AC in the rest of the house at night.

This is sortof what I do. The master bedroom in our place is south facing and I work nights, so I sleep in the day and I do like a bit of a cooler room (73 is usually what I shoot for). The problem is that I'd have to pull the rest of the house below that to get my room to be comfortable. It doesn't save me a ton of money, probably $5-10 a month, but being able to sleep and not be angry at my entire shift at night is worth it.

I'm eventually going to do a mini-split, I just haven't gotten around to it. That and blow in some more attic insulation. All on the to-do list.

 

[TooManyWheels]

Wife refuses to go with mini-split, says it looks like a hotel. *sigh*

They now have small cassette heads which will fit between 16" joists - Non-obtrusive head

 

[wander2039]

My regret is not putting in mini-splits when we replaced our central air/heat. Would of been almost the same price and way more efficient. I put the smallest one Mr Cool DIY had upstairs and it can almost cool the entire house even being upstairs. Right now have a wall unit for the boys room since apparently they have alot of hot air.. it's a pain to take in/out every year and we usually take it out if we're gone.

 

[fsdork]

I have a Midea U inverter window unit on its 3rd season. I've got it installed on the top level of our house, in the bonus room which is at the top of the open-railed staircase to the main floor. It does a great job (relative to its capacity, of course) of chewing away at the heat in the open spaces. I have no doubt that a 5K BTU unit would be way more than enough in any of our bedrooms.

The nice thing about the "U" design is that it works like a quasi mini-split, so the noisy parts (besides the fan that circulates the indoor air) are isolated to the exterior. Also, the window can still almost completely close.

I haven't got any energy consumption data to share, unfortunately. I can say that I don't get the sense it's having a massive effect on our electric bill, but of course that's all relative to usage.

The app is very handy for adjusting settings on the go. If I'm at work and realize it's getting hotter than I anticipated on a given day, I can turn the unit on from anywhere I have cellular data or Wi-Fi and keep the dog cool until I get home.

 

[alarmguy]

Yes, without question leaving your house 5 to 10 degrees warmer and a window AC unit to cool only the bedroom would save you money. Do not be tempted to get an oversize unit. No matter the room size (considering a standard size room) a 5000 to 6000 BTU is fine.

 

[pcoxe]

Wife refuses to go with mini-split, says it looks like a hotel. *sigh* At least in NH our a/c season is only really bad for 3 months or so. Not about to do central air too soon (maybe after I win the lotto that I don't play).

My wife is odd (but whose wife isn't?). She likes to bundle up--cold room so she can pull out the blankets. I like it cool too but for me a fan goes a really long ways.

Hotel units are more like through-the-wall window units. Splits are very unobtrusive.

 

[JHZR2]

I’ve been preaching mini splits for years.

Not cooling your home and just cooling a space can save lots. But it is kind of climate dependent. The number of continuous 90+ days for us is very few. The need for central air is limited. In other locations where it’s hotter, the whole house would get nasty, ymmv.

But I can’t see a house kept at 82 or so, with fans and some humidity removed, to be that bad… then cool one room to sleep.

 

[AZjeff]

Cost of mini-split + install vs window shaker is pretty far apart.

 

[supton]

But I can’t see a house kept at 82 or so, with fans and some humidity removed, to be that bad… then cool one room to sleep.

82? I'd probably be sweating just sitting and doing nothing at 82... probably depends on the humidity?

Hotel units are more like through-the-wall window units. Splits are very unobtrusive.

I am 99% sure that my wife is 100% against this:

I wouldn't care, not in our bedroom, nor in an office space. But I will agree, one is stuck seeing it the 8 months of the year that it's not doing anything (unless if you can heat with it, and your electric less than oil).