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AR15.COM
9/29/2016 7:08:23 PM EDT
So, it looks like I can get a 24,000 BTU window air conditioner for < $600. Is that really equal (in cooling capacity) to a 2 ton central a/c unit?
9/29/2016 7:44:24 PM EDT
[#1]
Not really since window units are designed to cool just one room not a full house like an HVAC system is.
9/29/2016 8:07:36 PM EDT
[#2]
Quoted:
So, it looks like I can get a 24,000 BTU window air conditioner for < $600. Is that really equal (in cooling capacity) to a 2 ton central a/c unit?
View Quote



Distributing the cooler air is the problem.

Central air uses ducts to deliver it based on calculated loads for each room.

2 tons in one room may make it cold and damp.

It will cool the room and cycle off the compressor (if not the fan also).
The runs will be short and not remove the humidity from the air.
Cool and damp.
10/1/2016 6:04:19 PM EDT
[#3]
With window units I would go with the smaller 5 or 6k units.

They are cheap about $100- 150 each, 115VAC so no special outlets needed to plug them in. They are pretty light and easily moved

You would then have temp control on each room they are in
10/3/2016 1:42:15 PM EDT
[#4]
I am trying to cool one big room so distribution isn't really an issue.
10/3/2016 7:10:22 PM EDT
[#5]
Quoted:
So, it looks like I can get a 24,000 BTU window air conditioner for < $600. Is that really equal (in cooling capacity) to a 2 ton central a/c unit?
View Quote


Yes.   The operating cost isn't pleasant...  Do you have a spec sheet for the unit?

If it's your house and plan to stay there, consider a mini-split.
10/4/2016 12:16:37 PM EDT
[#6]
Quote History
Quoted:
I am trying to cool one big room so distribution isn't really an issue.
View Quote


The larger ones start having a decent amount of fan noise to distribute in larger volumes.

You can also consider multiple smaller units.

It is not that hard to sleeve mount most units under a window either.

The window structural framing is already transferring the building loads around the opening.
10/5/2016 11:13:15 AM EDT
[#7]
Our house is 3500 sq ft, two story, over 100 year old, no AC, in Midwest.

When we moved in, there was one large AC window unit on the stair landing, and a couple smaller window units for the bedrooms.  In the middle of summer, they all ran all day to try to cut the humidity and keep it cool.  They worked but they ran all the time.

Eventually the large AC unit stopped putting out cool air.  My brother in law is an AC guy so he looked at.  He tried to clean the coils, and said that it wasn't designed to be recharged, so that was about all.  We never got it going again, so it's gone and now we just have more small units in the kitchen and living room to help make up the difference.

My biggest complaint about the window units is the mold.  All of them have black mold growing in them, which I am very allergic to.  This year I bought some mold cleaner and coil cleaner, and I am trying to clean them up before I put them away.  It's amazing how gunked up the coils are, and how much mold is in there.

Our local heating and cooling shop quoted us about $6000 to install an attic AC unit that would just cool the upstairs.  They said that since the walls are plaster and lathe, it is too risky to try to run conduit down the walls.  So every 3 years or so we find ourselves replacing window units that aren't cooling very well, and they are about $200-300 each.  We can afford the one or two hits, but not $6000.  

Cost wise, if we spent $600 on a large window unit every third year, it would give us fresh, cool air for 20 years or so (with the use of small units for bedrooms, occasionally replacing those smaller units).  If we spent $6000 it would cool the whole upstairs for 20+ years with minimal servicing.
10/5/2016 4:08:59 PM EDT
[#8]
There are no fittings on window type units for many years now.

They charge them and crimp off the lines.

The fittings, gas, braze, refrigerant, etc. make it less expensive to replace the thing.

If it dumped refrigerant the odds are very good the next thing to go will be the bearings in the fan motor.

Most use a single motor for the interior, exterior, and slinger.

The compressor is a separate hermetically sealed unit.

A loss of refrigerant often toasts at the compressor motor.
You cannot tell until you do all the work and it still does not run well.
10/6/2016 11:49:22 AM EDT
[#9]
In a situation like yours a mini split is the way to go. With each room able to independently control the temperature, you could have it warmer in some rooms lowering the cost to cool but have it set on a point that it can control the humidity. They have also come down in price, since they were first introduced many years ago. Efficiency wise they are just about they best out there. They also only require a small whole to be cut and if you have a quality and skilled installer the disruption can be minimal.

The other thing you can look at is how the humidity is getting into your home. Is it dude to the way the window units are in the widow and not sealed tightly or is it due to the age of your home. Being over 100 years old there are ways you might try and seal it up to prevent the humidity from getting into the home.
10/6/2016 2:08:08 PM EDT
[#10]
Quote History
Quoted:
In a situation like yours a mini split is the way to go. With each room able to independently control the temperature, you could have it warmer in some rooms lowering the cost to cool but have it set on a point that it can control the humidity. They have also come down in price, since they were first introduced many years ago. Efficiency wise they are just about they best out there. They also only require a small whole to be cut and if you have a quality and skilled installer the disruption can be minimal.

The other thing you can look at is how the humidity is getting into your home. Is it dude to the way the window units are in the widow and not sealed tightly or is it due to the age of your home. Being over 100 years old there are ways you might try and seal it up to prevent the humidity from getting into the home.
View Quote


Be very careful in a 100 year old house with humidity control.

A single mistake can result in damage that may not show for years and be very difficult to repair.

If you have plaster interior walls even adding insulation cab be problematic.

Just smile at your nice flat smooth walls and pay the HVAC bills.



10/6/2016 2:50:27 PM EDT
[#11]
Thanks for the extra info guys.  I think it is all relevant to the OP's original question and helps with the overall comparison.

By mini-split AC I am assuming you are referencing something like the Mitsubishi ductless AC units.  We have been looking at those as options for cooling the primary rooms that are used.

With reference to humidity control, during the summer we just want the air to be cool enough to cool ourselves down after working outside.  During the winter we run a large humidifier in our music room to try to maintain as close to 40-45% humidity for the instruments.  

OP: What are you using the room for, and why are you looking at window units instead of installed unit?
10/7/2016 10:32:32 PM EDT
[#12]
The mini splits also heat so they would lower your heating cost too. By allowing you to lower house temp and use the mini split to heat the rooms you are in
10/13/2016 10:06:04 PM EDT
[#13]
Very good stuff here. Thank you for the replies!
10/14/2016 6:39:57 AM EDT
[#14]
This thread turned to a subject that is relevant to me. I have a 1400 sqft raised ranch build in '71. I bought it in good shape in 2012, its well built but very dated. I've been updating it slowly. A HUGE upgrade for me this spring will be a single ductless minisplit on ome side of my house.
It accommodates 3 zones, of which i will be using two. One evaperator in the den/bathroom downstairs, and one larger evap upstairs in the dining/livingroom/kitchen. This single mitsubishi mini split will cool half of my whole house, and provide humidity control, affordably, and extremely quietly in a TINY footprint. I'm VERY excited about it.
Guys on garagejournal are CONSTANTLY reporting full installs and costs. It's insanely attractive. It also heats, altho thats secondary as i have primary and secondary heat in house already in the form of Ng hot water baseboard and a wood stove.
Ultimately i will also instlal a second mitsu minisplit on the OTHER side of the house for the bedrooms. 2 units for the WHOLE house.
I strongly suggest looking into those.