Reduce your Electric Bill with a Window Air ConditionerPosted on Jul 29, 2008 by Paul WhiteIntroductionOur house is newer ( built in 2005 ).  So of course you would think that maybe it would have newer stuff.  Wiring, Appliances, and most of all a newer AC unit.  Well it turns out that with most newer homes one of the things builders skimp out on is a high efficiency AC unit.  After reading the sticker on ours I found that it was a 10 SEER unit.  The year after our house was build the lowest that could be installed in a new home was raised to 12 SEER by federal law.  Our Utility costs are about 15 cents / KWH.  Last month we went through over 2000 KWH.  I am not sure if Global warming is to blame but one thing I did notice was the average temperature for the month of June was 94 degrees,  compared to 88 degrees last year.  We used 600 KWH more this June than last.  What is a KWH?For those of you who don't have a concept of what a KWH is here is an explanation.  Its basically how many 1000 watts you consume in 1 hour. 

Lets say you have a 60 watt light bulb. And you leave it on 24 hours a day.  This bulb consumers .06 KWH.  This times how many hours you leave it on will give you your KWH usage. Utility companies charge per KWH.  This rate can vary from 4 cents up to over 25 cents / KWH.  Here in Texas we pay about 15 cents / KWH.  The ProblemBy far the biggest consumer of electricty is your home's Central Air Conditioner.  After doing some research I figured that this was the cause of our high electric bills.  Unlike many, both me and my wife work out of the home.  Since we both work out of the home we don't have the luxury of turning down the AC during the day.  But then the problem is not so much that we have home offices, but it is that I like it to stay around 72 and my wife is comfortable at 75.  My office is towards the front of the house, while hers is at the back.  Now the question is why should I keep 2000 SQFT of house 72 degrees when I only need about 150 SQFT ( my office ) to be comfortable during the day. 

After talking with some people, I realized that we could benefit from upgrading our home's Air Conditioning unit, but this would cost around 8K-12K.  This would cut our electric bill in half, but it would take several years to make up the difference.  I also looked at installing solar panels, and or a wind Turbine to make up the difference. used portable ac units for saleBut each of these options were more expensive than just upgrading our home's AC unit.air handling unit price listThe SolutionThe conclusion I came to was that the only solution was to install a dedicated window air conditioner in my office.  replace a central air conditioning unitI had browsed some stores online to get a feel of the cost.  I found the perfect little unit at Sams Club. 

It was a GE 6000 BTU Window unit that cost about $148.  The unit came with a digital display, remote control, and all installation hardware.  The installation was easy.  The unit has a special energy saving mode, to help keep energy usage to a minimum.  It also has more than enough cooling power for my little office.How much Power does it use?One of the biggest concerns I had was how much power would it consume?  I used my Kilawatt meter to see.  When the fan is going it uses 50-60 watts.  When the compressor is on it uses 500-650 watts.  I have the meter running on it to track what its total usage is within 24 hours.  This will help me guage how much it will cost me to operate this for the month.  Of course by using this instead of Central Air Conditioning, should save me a bundle.  I estimate this window unit will pay for itself in 1 month.UpdateAfter tracking the usage for 24 hours. ( 14 hours  on ).  and with my thermostat set to 72, the unit consumed 4.46 KWH.If we multiple this by 30 days in a month we get 133.8 KWH. 

Times my utility rate of 15 cents / KWH = $20.07.So on average to run this unit in my office 14 hours / day it should cost me about $20 / month.Yesterday I was at Lowes. and I noticed they have a window AC unit for under $100.  It didn't have any of the cool features like energy saver, or digital display or a remote control, but it might get the job done.  If you have a membership at Sams Club, you can't go wrong with the GE brand window air conditioners. Categories associated with Reduce your Electric Bill with a Window Air ConditionerHome OwnershipSaving Energy Needed to confirm comment, but not made public. Email me when someone comments on this blogWith summer almost over and the August utility bills paid, you may be feeling a little poorer.  You feel like your electric bills were a lot higher during the summer than the spring, but why? Doesn’t the sun stay up longer, reducing your need to turn on lights? Well yes, but then you remember, you and your roommates have been running fans and window AC units all summer!

How much of an impact did this have on your electricity bill? And which is the bigger energy hog, the window fan or the window AC?? As an energy nerd and a roommate in an apartment with four window fans and one window AC, I have wondered about how much of an impact running these appliances during the summer has on our electric bills.  I decided to do a couple of calculations to measure energy usage, and was easily able to realize how much of an impact each appliance has on my apartment's utility bills.  I have to admit, I was a bit surprised by just how much each uses!  Learn how you can figure out just how much your cooling appliances are costing you with these 7 steps. This step was really easy for me because I use WegoWise to track my apartment’s energy use, so I clicked into my account and downloaded my data.  However, if you keep track of your bills online through your utility company's website or keep paper copies, you can organize your usage in a spreadsheet, or, if you're really old school, just write them down!

This isn’t scary, I promise! All you have to do is pick out the three months where you have the lowest usage, and then average the usage.  This average will serve as your baseline, and represents the amount of energy you use consistently each month.  For instance, it takes into account the energy you use to run your refrigerator, cooking appliances, TV, etc. For more information on calculating your baseline energy use, check out this blog article. My three months with the lowest usage are March, April and May.  Averaging out the usage, my roommate’s and my baseline energy use is 138 kWh.  Not too horrible, huh? In some instances, the watts will be right there on the appliance. In other cases, you may have to do some simple math to calculate the watts. Don’t worry, you learned this equation in physics class!  Remember Watts = amps x volts? Either way, you'll be able to find the information you need somewhere on the appliance, either as a sticker on the side or back of the appliance, or on the plug.

Sorry for the blurriness, but here's an example of where you might find the information you need.  In this case, I had the Amps (A) and the Volts (V) provided, so I was then able to calculate the Watts. My roommates and I have a combined four window fans and one window AC unit.  The wattage of the AC unit is 515, while the window fans are 48, 60, 66, and 70 watts. If you can add 2+2, and then divide by 4, you can do this step! Just divide each of your appliances’ wattage by the total wattage of all your appliances.  515 +48+60+66+70 = 759 total watts for my apartment's cooling appliances Window AC unit: 515/759 = 67% of total energy! Window Fan #1: 48/759 = 6% of total energy Window Fan #2: 60/759 = 8% of total energy Window Fan #3: 66/759 = 9% of total energy Window Fan #4: 70/759 = 9% of total energy After talking with my roommates, I realized we all used our fans and AC unit pretty much the same amount – we only had it on at night, and we only used them during the hottest days of summer, which were in July and August. 

In July, we used 244 kWh, and in August, we used 225 kWh. Now that you know the monthly usage, you can use that usage and your baseline to determine the excess usage from your cooling appliances.  To do this, add the usage from the months, multiply your baseline by the number of months you used your cooling appliances, and subtract this value from the total usage.  244 kWh + 225 kWh = 469 kWh used in July and August 469 kWh – (138 kWh x 2 months) = 193 kWh from cooling appliances If you’re like my roommates and I and have used each appliance about the same amount, this is probably the easiest step! Just multiply your excess usage by the proportion of total energy each appliance uses. If you've used your appliances at different frequencies, you'll also want to take into account the total time you ran each appliance. Here’s the breakdown for my apartment’s appliances: Window AC unit: 130 kWh Window Fan #1: 12 kWh Window Fan #2: 15 kWh Window Fan #3 & 4: 17 kWh