A load calculation is recommended when installing a new heat pump, furnace or air conditioner. It is also recommended when making changes to a pre-existing system. Many changes that people make to their home is adding on rooms and installing new air conditioners. Anytime you begin a project, you need to do a load calculation to ensure that the air conditioner, heat pump and ducts are sized appropriately for the home or add on room in question.
In Tulsa Oklahoma area, when we do a load calculation, we want to determine what size heater it will take to keep the home at 70-75 degrees on a 6-14 degree day and we want to determine what size air conditioner is required to keep the home at 70-75 degrees with a 40%-50% relative humidity on a 96-103 degree day. Also, we need to know how to distribute the air evenly through the home once the sized unit is determined. We need to know what size the ducts should be to move the air 200-500 fpm velocity through the ducts and maintain a Total External Static Pressure on the system of less than .5″ water column.
We accomplish these determinations by doing an ACCA Manual J for system sizing, an ACCA Manual D for duct system sizing and an ACCA Manual S for equipment selection.
Normally, you will have to pay for a load calculation as they require 8-12 hours of time to complete and possibly more for multi zoned homes. You can expect an ACCA trained technician to measure all aspects of your home and document all construction materials used in your home. You will need to provide your personal use information like where you hang out during the hottest parts of the day in your home, whether or not you have large groups of people in the home during the summer months and where appliances, computers and plants are located. Once this stage of planning is completed, you can rest assured that all your “ducts are in a row”. This will ensure a long lasting, high performance installation that cannot be claimed to be improperly installed.