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Manual-J HVAC Engineering Software



     How does a heating/cooling contractor know the correct size of equipment to put into a structure and how do they know how to put the ducting in so the home will be comfortable everywhere?

     The code says that a heating/cooling contractor is to perform "Manual-J" engineering to know the correct size of heating or cooling equipment that is needed. The envelope of the structure is what determines how rapidly the heat will leave the structure (referred to as "heat loss"), and how rapidly the structure will absorb heat (referred to as "heat gain"). In simple terms, Manual-J looks at three items: the structure, the orientation of the structure, and the customer's expectations for comfort (referred to as "design temperatures"). This analysis is needed regardless of the heating/cooling system (unless you are using an evaportive cooler). If you are using a ducted system, read the following about Manual D.

     The code further states that once a contractor has used applied Manual-J engineering to assess the heating and cooling needs of the structure, they are then to use "Manual-D" to perform the duct design. If the air distribution system is not installed correctly, it is a total guess as to how the air is going to get to the rooms. Air has mass and weight, and how you are going to transport it from the furnace to the final destination needs to be designed. Heating Equipment Company will not throw a dart with your life savings or our reputation.

     Why is Heating Equipment Company such a strong proponent of Manual-J? By taking into consideration the factors of the insulation values of doors, windows, walls, ceilings, and floors, the number of occupants, the number of fireplaces, the number of appliances, design temperatures, type of equipment, equipment location, type of materials used, roof materials, ceiling design, type and lengths of ducting, home position in relation to the sun, outside ground types, and specific area elevations, it can effectively eliminate any guesswork regarding  the appropriate size of equipment for your home. After the analysis, current utility costs are entered, and a cost comparision of several different systems (i.e. oil vs gas vs electric) is possible. The multiple benefits of this software is specifically why Manual-J engineering has become synonymous with a quality HVAC company. If your home will be evaluated in this way, plan on 1-2 hours for us to be at your home to gather informaton for this analysis. NOTE: Heating Equipment Company has been using this software since 2001 for every new home and most remodels. The Wrightsoft Manual-J and Manual-D (duct design) are ACCA certified.




We draw the home into the computer noting the orientation and construction of the home.

     After selection of equipment that meets the home's requirements for how much heat it loses in the winter (heat loss) and how much heat it absorbs (heat gain), we design the ducting. This illustration is for a hard metal duct design. Metal ducting is considered the best for durability, aggressive cleaning, and is rodent proof. It is the most expensive material to install.

     This is an illustration of a flexible-ducting system. Due to decreased material cost and labor time for installation, flexible ducting is common is most homes. Rodents being able to chew through the material is the major drawback of this type of system. Flex material cannot be cleaned as aggressivly as metal ducting and the materials do not have a lifetime warranty.

CAD drawings may be imported to our software for ease of use.



     Report pages are available for documentation about the analysis process. These reports are necessary for building permits where engineering is required.