It is important to calculate the size of the air conditioner that is actually required by your home, before installing one. Here is more information on the factors that must be considered before you install an AC in your house.
The task of sizing AC is a matter of application of the science rather than the art. You can use an on-line calculator to determine the size of air conditioner, that can make your home a hospitable place in the hot and humid summer. A properly sized AC can work efficiently and help you realize your investment. On the other hand, under-sized ones will run continuously, without cooling your house and without providing succor and worth. The over-sized air conditioner will not work more efficiently than the properly sized one. It is up to you to decide whether to install one of the portable or central air conditioners that are available in the market.
Steps to Follow
- The first task is to measure (in meters) the length and the width of each of the rooms in your house that you plan to cool with the air conditioner.
- The height of the room does not play any role in this calculation, because the cool air is heavy and sinks toward the ground.
- Find the area of each room you are interested in by multiplying its length and width.
- By adding together the areas of all the rooms you are interested in, you will arrive at the total area in your house to be cooled.
- Multiply the total area by 337 BTUs and the product will give you the amount of heat, an air conditioner will have to remove from your house in order to cool it. The term BTUs stands for British thermal units.
- Wait, your task is not over, yet. There are few more calculations you have to do, in order to calculate air conditioner size for your house. Calculate the area of each of your south side windows (width times height). Total the area of the windows and multiply it by 871 BTUs. This will give you the amount of heat entering your house through the south side windows.
- Calculate the area of the each north side window, add them up and calculate the amount of heat entering your house through the north side windows by multiplying the total by 166 BTUs.
- Multiply the number of people by 400 BTUs, the amount of heat generated by each person per hour.
- Now, we need to calculate the amount of heat generated by each of the light source in your house. We do it by multiplying number of watts per light source by 4.25 BTUs.
- If you have electrical appliances or machines in any of the rooms you want to cool, then you will have to figure out the heat produced by them while they are in use. Multiply the maximum wattage an appliance can operate on by 3.15 BTUs.
- Although, you may not always run an appliance at full capacity, it is better to have a heavy-duty air conditioner that can handle more load when the need arises.
- Add all the BTUs figure for the appliances in the targeted rooms.
- Obviously, the last step is to add up all the BTUs amounts that you have calculated for the floor, windows, persons, light sources and appliances.
- Add 2,000 BTUs to the total to compensate the heat generated the kitchen during the cooking.
- The resulting amount will be the total amount of heat, an air conditioner will have to remove from your house, to make your stay pleasant.
- If you are interested in knowing the capacity in tons of A/C you will need to buy, then first use an online calculator to convert the final total (in BTU) to KWh and then KWh to tonnage calculator.
Calculating air conditioner size is a very tricky business as few other factors such as whether the windows are internally or externally shaded, whether they are double glazed or single glazed, types and quality of insulation used for the floor and ceiling, size of the doors connecting rooms and the time they remain open, elevation of the house, whether the house is shaded by other buildings (trees) or not, etc., also matter. When you take the decision of buying an air conditioner, you must choose one that can at least handle the amount of load you have arrived at. Don’t get stumped with the amount of cooling your AC will have to do, because an air conditioner with one ton capacity can remove 12,000 BTUs of heat from a closed area.