Reduce your Electric Bill with a Window Air Conditioner

One of our central air units went out (leaking at the coil drip pan), and it's over $1,000 to replace.  The system only cools our kitchen, familyroom, and on small bathroom, and another room that is used as storage only.  We bought a 8,000BTU unit to keep the family room cooled, and didn't realize it is cooling the entire 600 square feet.  It doesn't run all the time, when in energy efficient mode, and auto.  We have spent up towards $400+/month when running both central air systems, and the house never really cools down.  With the window unit and the other central air system unit (cools living room, 4 bedrooms and full bathroom) the entire house is much more comfortable, even during 90F plus days. We have it set for 80F.  I can't wait to see the savings just from doing this.  I think you have to be foolish to burn money with central air.  A lot of the cooling is wasted anyway.
I love this article and all the feedback.

I Thank you for posting all these articles comments, and stories I have a less then 800 square foot home and my AC bill has been pretty high even since it was two people and now one the last three years , Im about to install an 10, 800 btu A/C wall unit and turn off the central a/c it wold cost almost 3000 thousand dollars to replace in order to get the same billing, from this post , I thank all the contributors for taking the time to write , cause it sure gives a guy relief  to know , he's headed in the right direction specially  on a budget

I have recently moved from a place with central air. Summer months were outrageous. In the new place we just installed two units soon to be three. The only concern have is that they are slightly older. I'm concerned this may in fact effect cost. I find comfort in reading other posted comments in central verse unit but still question the age of the units. Anyone have anything to offer?

Julie,

Check the EER rating of your window AC units.  If there is no sticker lookup the model online to get that information.  Most newer window units from what I have seen don't get much higher than an EER of 11.  We upgraded our old central AIR unit from a 10 SEER to a 16 SEER, and our enegy bills dropped almost in half.  If your new home is small, then windows units can work great, just make sure you insulate around the units really well.  use tape and expanding foam to prevent any thermal leaks.  I still have my window units in storage.  As they are great in case you have a power outage and need to keep your home cool off a generator or large UPS.

Thanks Paul! I'm not sure where I'd find the ratings  as most of the units are worn. The one is a 1998 8000 but Fedders this i know from picture match. The space is not very huge but not tiny. For now  I have one in bedroom in hallway and one in living room. I've closed off other bed and chocked the bottom of the door until the other is installed. All other rooms are sealed and the house has  cooled down in 35 minutes. I'm now thinking I've  been over thinking and it may be OK! :) Thanks!!!

Same guy who posted last year well with 752 square ft my unit cools entire house freezing with 10, 800 btu unit never turn it off only in the morning  cause it's too cold , and in winter I didn't use it I spent about 75, a month for ac on alll day and night and in winter 42 entire bill

I just bought a new one LG with yje the on off timer 12 seer I plan to save even more 

Thats inspiring News Joey!  what kind of KWH rates do you pay where you are located?  I am at about 8.5 Cents / KWH in Houston.

Trying to decide whether to go with my BIG swamp cooler or try to find a small high EER A/C unit. I'm off grid in NorCal and my little swamp cooler that I've had for the past 20 years died from water pump issues. I have 4 100w panels (upgradeable to 6) and am currently pulling in about 275-300 amp hours per day. I hope to have enough to run both whichever cooling unit I go with as well as my internet connection as well as my pc or laptop.

Note to those going with the attic fans: My folks had one installed in the attic of their place in Pasadena with a temp. switch set to turn it on at 100°. It worked fine from 1976, when it was installed, till 1993, when the bearings packed it in and it started a fire that pretty much burnt the house down.

Luckily, Mom was back visiting kinfolk in North Carolina when it happened...

Hello, we have been using a 8000 but unit in our living room for about 4 years now. We have an older home unit that needs replacement, and with the housing market being so volatile and money being so tight (mother retired on a small pention) we decided to install a window unit because I work during the day, and my mother spends most of her time in the kitchen/ living room. Added 2 more to each bedroom and Electricity bill has been under $200 even during summer. We live in Florida as well, so that is impressive to stay below $200. I noticed a few months back that both of our adjacent neighbors have adopted our idea. These comments are great proof that this really does work. Thank you everyone!

Just wanted to provide an update on window acs.  Most (mid 2016) are around 12 eer(most use ceer ratings which isn't directly compatible with seer or eer, but you can still calculate eer by dividing BTUs per hour by watts) right now and the highest I've found is 12.4 eer for some new ge and Chinese models.  This is roughly equivalent to about 14.2 seer for a central unit.  What that means is that they're essentially on par with central AC efficiency and could be quite better once you account for duct losses which are commonly upwards of 20%.  It's a myth that they are less efficient.  Furthermore,  because they're so cheap it's easy to zone your house like Paul did and replace them in a couple years with more efficient models as they come out rather than being stuck with a big expensive monolithic system.   I haven't found any with ECM fans yet like mini splits and efficient air handlers use.  I think those will boost eer even higher in the coming years.  There are a few connected window acs now, but they mostly only support proprietary apps.  I expect soon we'll see ones that support more common home automation protocols so it will be trivial to program them to sync with whole house fans and based off other complex schedules, room occupancy and weather conditions.

Point being that there's almost no economic reason I can find to use central AC.    Maybe use central AC because it's quieter and doesn't block windows, but not because it's cheaper.

Great article Paul.

Tim,

really it comes down to astetics.  Some people don't want a dozen window AC units sticking out of their house.  We upgraded our home AC system with a 16 SEER, and our electric bill is under $100 most months.  Since then I haven't put our window units back in.  But of course our new AC system cost about $6k.  $150 window unit is hard to compete with price wise.  

I have a question. For a two bedroom apartment that is connected to the living room and kitchen by a long hall, would I be better off with 5000 btu units in each bedroom and one in the living room than trying to cool the whole thing with one 12,000 btu unit.  I found brand new 5,000 btu units for $99 with free shipping on Amazon and they are rated very high Energy Efficiency.  Thanks.

If my 5000btu is on at night and compressor does not kick in does it use as much electricity as if I left it on fan

Kay,

Yes if your leave it on and the compressor never runs, that is no different than the fan setting.  Same amount of electricity is used.  

Sheryl,

Generally the smaller ones would be better.  There's no gain in efficiency going bigger plus you can zone temps with the smaller ones and control area temps more precisely.  Only downside is you're now blocking three windows.

Kay,

Depending on your unit the fan uses between 20 and 90w when running.  I'd guess towards the smaller number.   So, basically having it run continuously not in the eco setting doesn't use very much energy at all as long as the compressor isn't kicking on.     And without the compressor on it's equivalent to the fan only setting wrt wattage and current draw.

Tim Johnson, Thank you for your reply. I went ahead and got the smaller units!

Central heat & air..  OR window unit... ( My home is 2000 sq ft )... All Electric.. I have central heat & air....

My electric bill was $2000 in 2014.....I went Solar Power 2015...with four 285 watt panels ( 2 for my electric hot water tank ) & ( 2 for my 1000 watt inverter.. with 4 lithium batteries ) my home runs on solar 90 %.... My electric bill 2016 was $650.... So far this year.. thru August 2017 =  $278...  With a whole house fan and.... ONE WINDOW A/C UNIT.. ( Running on solar )... My  Electric Bill... May = $2.97 /  June = $13.43 / July = $36.48 / August = $28.71....Most 120 volts window units will work on 1000 watt.. TOTAL COST for Solar Power & Batteries = $5500.... Will Recover this cost in about 5 years

  I am wondering if I save money by using the low cool vs. the high cool temp and the lTKPFU