I see window ACs and Heat Pumps advertised for like $400 for 18,000 BTU units.
Yet a replacement (no ductwork) package heat pump costs far far more. Two window ACs at $400 give you the BTUs of a 3 T central system – that would probably cost you $3000 + dollars for the central package unit “box” sitting in your yard..
Has anyone ever designed a small house with an area/alcove for two window units and used a standard air handler to move the cold air around?
It would sure simplify replacemet – just go the Waldo Mart and get another$400 unit and slap it in?
Replies
Noise, ugly, no distribution system, creates hot and cold spots, and did I say ugly. You will spend $400 every five or six years if they are used heavily for the life of the home. Eventual operating and replacement cost will exceed a well designed central system.
Dave
I guess my house has something like waht you describe.
We have 2 13'x26' rooms ech with a window AC mounted in a dormer. The ceiling fans in the two rooms, the hall and another room circulate the air. The three rooms are used as office space and have 8 computers as well as 4 people as heat loads.
With the electronic controls avaiable on new window ACs it seems a reasonable option.
Disadvantages of window ACs on a permanent basis include heat loss in the winter (if left installed) or the pain of installing/removing once a year if not permanently installed. Also, seen too much wall damage from condensation dripping into walls from inadequate installation from both the AC stuck in a window as well as those poking out the wall.
Don't get me wrong, if more people installed window ACs in thier walls and did it themselves, I'd make a good living repairing the damage.
We had a window unit once, but I spent 20 grand and upgraded the whole house with two heat pumps and oil backup. Been very comfortable since. And my back doesn't bother me nearly as much.
I'm not an HVAC expert by any means. But I suspect that you'd lose a tremendous amount of efficience with the window units vs. a whole house system. That would probably make up the price difference in a fairly short amount of time.
The downside of being better than everyone else is that people tend to assume you're Pretentious.
There have been some concerns about the efficiency difference between wall units and centeral units.
Lets look at some "real" numbers for the same sized units, 10k BTU.
Split unit (single room central air) installed is $2500.
Window AC installed in cesement window with the movable parts replaced with a custom panel using 2" of foam insulation and 1/2" BC ply on both sides is $400. (The insulation keeps the noise level near zero.)
$2100 difference.
The window unit consumes less than $50/month electric (more like $20/month but ...). The central unit $0/month. 3 Months cooling season.
14 years to break even for the central unit.
But what the heck ...
Life expectancy of the window shaker and your back if you do proper PMs on the unit? I don't know where you are located, but pulling a 10k window unit a couple of two or three times a season to wash it out is a must around here. If you don't, the efficency falls way off. Of course you need to wash out the condenser coils on a central unit the same number of times, but pulling a hose around the side of the house sure beat pulling a window unit. Believe I know. I have pulled, washed and reinstalled hundreds of window shakers in the past 18 years. My back tells me noooo, every time I see one now.
Dave
I'm no A/C expert, electrician and no too much of an expert at that either, but living in Florida and having an interest in living frugally I have noticed a few points.
Newer window units are not, EER, less efficient than many late model central units from a few years back. Even comparing the best central system versus a cheap window unit differences in energy used can easily be swamped by other factors. Cutting down a well placed shade tree can easily double the power used for cooling. Changing roof color, or material, and adding insulation to an unisulated attic can do much the same thing.
I wouldn't use small window units to cool an entire house. In smaller houses I have seen fans used to move the cool air. A little better, but a bit more expensive to run, was using the blower in the central heating unit, blower only and heat off, to move the air. Neither of these worked on anything bigger than a cottage sized home and then only when the house had good insulation and a well shaded lot to allow a reasonably sized window unit to keep up with the load.
The situation where window units shine and can save you money is where you can retreat to a small portion of the house. A moderately sized office or bedroom that can be isolated with dampers and doors can allow a small unit to serve while allowing the rest of the house to remain uncooled. Some of the better 5 to 8000 Btu units, don't go too big or you loose the ability to dry the air, are fairly efficient and quiet. I have experimented with my own house and found that I can save quite a bit by just cooling the rooms I stay in long term. This would be much more difficult and less efficient if there were more people.
We have a 1 1/2 story hydronic heat home. The first year we just cooled the top floor (sleeping). Worked fine. We could retreat to the room in the summer on the hottest days.
So, I agree that that would be the most efficient in terms of overall energy costs.
Once the baby came, though, we now have 3 units cooling our house. Problems:
- NOISY!
- Shake the house
- A HUGE pain to haul up each spring and clean out.
Granted, #1 can be remedied by getting the newer ones with electronic controls with timers and such.
#2 can be remedied with some serious installation hardware.
#3 could be remedied of manufacturs put handles on the units and didn't require one to unscrew 20 some screws to get into the damned unit.
In our case, the 3 units were $1000 compared to $9000 for mini-duct central. As much as I was happy with those savings, I'm rethinking the mini-duct system!
Wain: Just had a mini duct/high pressure central air system installed in my home. Thought serously about central vs window units. I have 2000 sq' -3bd 2 bath. Window units are definitely cheaper to buy however:
1. Would need at least 3-4 units which would have to come out every winter, go back in every spring. (Chicago winters)
2. No matter how new, they're still noisy. My central is very quiet.
3. Have to set controls on each unit. My central's on a programmable thermostat.
4. Yeah, i could buy new window AC's every year for a long while for what i paid for the central but heh, right now money's cheap, and i'm increasing the value of my house.
Just being able to touch a button and not having to remove and install every year makes it worth the money.
Life's short, be comfortable.
Jim
I assume that you live in a moist climate and can't use a swamp cooler. Is that correct?
Any jackass can kick down a barn, but it takes a carpenter to build one.
True.
I was just struck by the huge price dufference (on a BTU basis) between window units and central units.
I guess if a Milwaukee hammer drill is 5.5 amps at $130, but a Chicago Electric Impact drill is 8 amps at $99, it's a better deal? You do get what you pay for. Also, many (maybe most) window units are made in Mexico and China now, so that has a lot to do with the price. I do like the remote controls on the new ones though.