If you are in the market for a new air conditioner for your home, one of the most important questions to have answered is what size air conditioner you will need. The only true way to know what size air conditioner your home will require, is to have a load calculation performed. For load calculations, manual J is the industry standard, and should be used by your heating & cooling contractor. This program will take into account the weather data for your area, cubic footage of the home, exterior wall lengths, insulation values, type and size of windows, type and size of exterior doors, as well as the home’s directional orientation.
All of these factors are calculated in the program, and the heating and cooling demands of the home are determined. These factors are very important. The old stand by was to use square footage to determine the cooling load of a home. The problem with this method is that it doesn’t take into account all of the above factors. You can take the same exact floor plan, one house being constructed to the standards of 1970, and one with today’s efficiency standards, and each house will require a different amount of heating and cooling. Additionally, you can take the same floor plan, with the same insulation, window, etc., but one house may have a majority of windows facing north, while the other has majority of it’s windows facing south or west. These two houses will have different heating & cooling requirements due to sun exposure.
The goal of a load calculation is to provide the closest match of a heating & cooling system for your particular home. Many contractors cut corners here, because of the time involved, so if you are looking to purchase a new furnace and/or air conditioner, be sure to ask that a load calculation be performed. We perform the load calculations at no cost as a part of our proposal process. If you would like us to take a look at your home, please contact us.