FAQ’s – Contractors
Why do I need a Manual J?
It is similar to calculating the lumber needed for a specific building project: you don’t want to run short or purchase more than you need. ACCA Manual J is your calculation for the amount of Btuh’s (heat) required to be removed from or added to your home in order to maintain comfort. Any other method is guessing. It’s also required by the 2009-2015 International Residential Code. Not having one can also lead to issues caused by over sizing equipment, such as high utility costs and/or humidity levels.
What is the difference between ACCA Manual J and Manual S?
Manual J is the process used to determine the amount of Btuh’s (heat) required to be removed from or added to your home in order to maintain comfort. Manual S is the process used to select the appropriate equipment based on the equipment manufacturer’s performance data. This ensures the equipment is capable of delivering the Btuh’s determined by the Manual J calculation.
Who is responsible if the system does not cool adequately?
If the system fails to cool or heat after being installed per our design, then Enerlogic is responsible. Our calculations are only as accurate as the information you provided to us. With that said, you must also ensure the air distribution system you install complies with the duct configurations we used in the load calculations. They are provided with the Manual J report. Over designing or an inefficient design can increase the load just as much as using the wrong window or insulation values.
I’ve provided a duct layout for permitting, but the City has rejected my permit because I did not have a Manual D, what is that?
A duct layout is just that, a diagram of how the system is proposed to be installed. ACCA Manual D is the third procedure used to formulate the systems duct sizing. We use the information from the ACCA Manual J & S and the equipment manufacturer’s expanded blower performance data to determine the proper duct size. The Manual D also includes important information your technician will need to properly commission the system and the design room to room cfm for air balancing. Finally, the information from the Manual D, along with the ACCA Manual T grill sizing procedure, should be used to ensure the air will be properly distributed within a space as designed.
At Enerlogic we would be happy to answer all of your HVAC System design questions and provide you with design services in a timely manner.
- Enerlogic |
- P: (281) 947-3723 |
- E: firstname.lastname@example.org
- Office: 738 Highway 6 S, Suite 900, Houston, TX 77079
- Mail: 2211 Rayford Rd, Suite 111-213, Spring, TX 77386
- License # TACLA72189E