Friday, April 11, 2008

How to buy a window air conditioner

Someone recently wrote to me asking where to get a good window air conditioner at a great price. Because this is an excellent question and an item that you can pay WAY too much for, I thought I best share my answer with my readers.

When I lived in New England (where the winters are cold and the summers are hot and humid), I bought all my window air conditioners second-hand at yard sales at the beginning of winter. I usually paid about $20 and they worked great. The same air conditioner at a yard sale at the beginning of summer would cost about $60. At a store, the same a/c would cost at least $200. Need I say more?

If you don't live in an area that has drastically defined seasons, I suggest that you check out and get yourself a great deal on a second-hand air conditioning unit. Try to do this in the coldest part of the year, but Craigslist is awesome anytime of the year. If you don't know what Craigslist is, then read about it in my earlier blog entry.

Before you rush off on your bargain buying spree, this treasure hunt requires a bit of research and mathematics prior to embarking on the expedition for best hunting results.

The first thing you need to do is measure the space that you want to cool. You need to know the square footage. It's easy to figure out. Just measure the floor. Measure in one direction and then measure in the other direction. Then multiply the two numbers. Ta-da! Square footage.

Now take your square footage and multiply that by 35. That will give you a general idea of what SIZE air conditioner to buy. That doesn't mean how big in inches... it means how big in BTUs - British Thermal Units.

Every window air conditioner has a cooling capacity number that ranges from about 5,000 to 18,000 BTUs. (Larger systems are usually rated in Tons of cooling with a Ton being equal to 12,000 BTUs.) The higher the BTU value, the stronger the air conditioner is. BTUs determine how much cooling the unit can deliver in an hour. Too little BTUs and you won't get cooled off.... too many BTUs and you will waste energy and MONEY (yikes!)

(For those of you living in areas that actually have humidity here is a bit more insight: Many people buy an air conditioner that is too large, thinking it will provider better cooling. However, an oversized air conditioner is actually less effective — and wastes energy at the same time. Air conditioners remove both heat and humidity from the air. If the unit is too large, it will cool the room quickly, but only remove some of the humidity. This leaves the room with a damp, clammy feeling. A properly sized unit will remove humidity effectively as it cools.)

Once you determine BTUs based on square footage (multiplied by 35), make sure that you make adjustments for room location and heat load.

If the room is shaded, reduce the BTUs by 10%
If the room is very sunny, increase the BTUs by 10%
If the air conditioner is in the kitchen, add 4,000 BTUs
If the room is going to be occupied by more than 2 people (most of the time), add 600 BTUs per person.

Another thing to consider is EER. "EER" stands for "Energy Efficiency Ratio." Air conditioners' EERs usually range from 8.2 to 10.5. The higher the number, the more efficiency... and more expensive to buy... but cheaper to operate. It's a numbers game.

When installing your window air conditioner, use a window that is in the shade. Ensure that there is space around the inside and outside for air flow. In other words, don't put the air condition up against the back of your couch or right up against a bush outside. Insulate where the window and air conditioner meet to make sure there is no air leakage around the unit and the window. Make sure that you clean the filters on a regular basis as this will increase the efficiency and life of your air conditioner.

OK... those are my tips. Good luck and stay cool.

No comments: