Manual J, S and D

We Focus on Building Science and “Right Sizing” of HVAC Equipment

What is Manual J, S, and D?

We live in America where everything is bigger and better. It turns out that “bigger is not always better” in the HVAC industry. At Pro Energy Consultants, we are focused on building science and “right sizing” of HVAC equipment is our goal. Most air conditioners in America are over-sized because contractors use the old “rule of thumb” method, and this is wrong.

Pro Energy Consultants works with Architects, Builders, HVAC Contractors, and Homeowners who want to make sure they are installing the correct HVAC equipment in their homes. When sized properly, this equipment should last a long time and provide efficient energy consumption.

Manual J
Is for determining how much heat the house loses in winter and gains in summer. You do this room-by-room for the whole house, which allows you to determine how much conditioned air each room needs for both heating and cooling. It factors in all the surfaces of the building envelope, with their areas and insulation levels. Each wall is given its proper orientation, because windows and doors are attached to them. Other important data include the location and tightness of the duct system, the infiltration rate of the house, the internal loads (appliances and people), and where the house is located.

This calculation determines how much heat the house loses in winter and gains in summer. Many building elements are accounted for in this calculation such as room volume, building structure materials, building geographical orientation, window size and energy rating, among many other factors. This scientific analysis of your home is critical to ensuring the HVAC system is “right sized”.

Manual S
Once you know the amount of conditioned air necessary in each room, you have to select the equipment. What air conditioner, heat pump, furnace, or boiler are you going to install? This part is critical with forced air systems because every piece of equipment has different characteristics – sensible and latent capacities, the amount of air moved, and the static pressures.

Manual D
Finally, once you know how many cubic feet per minute of conditioned air you need for each room, what equipment you’re using, and how you’re distributing the air in the room, you can design the duct system. Here you look at the location of the air handler, the distance to the ducts, how many turns the ducts must make, and how much air needs to be delivered. The type of duct has a big impact on the results, as sheet metal ducts have a lower friction rate than flex duct or rigid fiberglass duct board.

Manual J has been used and is required by code in many states for new construction but it can be used for replacement equipment as well. Please call us at (630) 770-4994 to learn more about Pro Energy Consultants Manual J services.

Pro Energy Consultants Oversized Air Conditioner

Did you know that over-sized AC equipment is one of the worst problems homeowners have?

Pro Energy Consultants Manual J Reports

When Pro Energy Consultants has completed the Manual J, S and D reviews, we will give a complete detailed report documenting our findings.