Often a duct design is simply called a “Man J Report” or a “Manual J”, an HVAC Design is “simply” putting together all the information needed to install an HVAC Comfort system in a new or existing home. However, this isn’t as simple as it may seem. Historically, many HVAC Contractors have used “rules of thumb” methods for deciding what size of furnace and air conditioner to install in a home. Often, the square footage of the home was used. Unfortunately, some are still using this method. You can even find this “sizing method” on the internet.
But what if a 1500 sq. ft. house is built in northern Montana, or southern Arizona? Would the furnace and air conditioner be the same size in both locations? Common sense says no. Thankfully, though, we have scientific ways to figure out the proper HVAC sizes for any house. And, the location and construction materials can all be accounted for.
A full HVAC Design includes a Manual J load calculation, equipment selected based on Manual S and a duct system based on Manual D. Interested in learning more from the organization behind the manuals? Visit the ACCA.Org site.
