Reduce your Electric Bill with a Window Air Conditioner

Reduce your Electric Bill with a Window Air Conditioner

Posted on Jul 29, 2008 by Paul White

Introduction
Our 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 Problem
By 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. But each of these options were more expensive than just upgrading our home's AC unit.

The Solution
The conclusion I came to was that the only solution was to install a dedicated window air conditioner in my office.  I 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.



Update
After 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. 

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