HVAC Design Partners are excited to introduce our one of kind Planned Occupant Comfort and Indoor Air Quality Package.
To properly design a heating and air conditioning system intended for a residential application, An ACCA Manual J load calculation, (using an Air Conditioning Contractors of America- ACCA approved software), ACCA Manual S equipment selection, ACCA Manual D Duct Design and ASHRAE 62.2 Ventilation calculation should be applied. This method of design is now required by Green Building programs like LEED for Homes and Energy Star as well as Building Codes in most municipalities nationwide. While some HVAC contractors and builders view the ACCA Manual Design Process as an unnecessary burden, professional- HVAC contractors, and builders interested in providing their clients with the best product know that the goal of a quality HVAC design is total occupant comfort. Comfort is driven by several factors including temperature, humidity, air velocity and noise. Planned occupant comfort starts with a quality HVAC Design. But the proper design is not the end of the story.
Once a HVAC Design is completed and turned over to the client, it is then up to the HVAC Contractor to properly implement it and verify the system is working as designed. This is where the best of designs often fails. Organizations like RESNET and Energy Star have recognized that the even though HVAC Designs were being reviewed to a certain extent by 3rd party Raters, just collecting a form filled out by the installing contractor was not ensuring that the HVAC system was being set up as specified by the design. They found that most of the systems installed in Energy Star Homes were not operating at the rated efficiency because of things like incorrect air flow, over amping due to high static and incorrect refrigerant charge. This led to the creation of "ANSI/ RESNET/ ACCA 310 2020 Standard for Grading the Installation of HVAC Systems".
ANSI/ RESNET/ ACCA 310 2020 Standard for Grading the Installation of HVAC Systems "provides a methodology for evaluating the installation quality of Unitary HVAC systems. It's comprised of five tasks - a design review, a total duct leakage test, a Blower Fan volumetric airflow test, a Blower Fan watt draw test, and a non-invasive evaluation of refrigerant charge. -This standard establishes the procedures, tolerances, and record keeping practices for evaluating and grading elements of an HVAC System's design and installation. This standard is intended to support consistency in energy rating and labeling."- ANSI/ RESNET/ ACCA 310 2020 Standard
Standard 310 is a basic "commissioning" verification designed to verify the system was installed per the Energy Star guidelines. It covers the fundamentals of commissioning a system but leaves out the crown jewel of a commissioning report which is the rating of the HVAC system performance. Enter "ANSI/ ASHRAE Standard 221-2020 Test method to Field Verify and Score the Cooling and heating Performance of an Installed Unitary System".
ASHRAE Standard 221 "provides a method to field measure and estimate the capacity and efficiency
and score the performance of an installed heating, ventilating, and air-conditioning (HVAC) system. An installed system's performance deteriorates because of less-than-perfect design and installation practices and poor maintenance. System airflow may be below the volume specified; system static pressures may be above the maximum allowable; duct systems may be undersized, poorly installed, or damaged; refrigeration circuits may be incorrectly charged; and combustion deficiencies may prohibit the delivery of equipment rated capacity".- ANSI/ ASHRAE Standard 221-2020
At the point 310 testing is done, the system airflow and temperatures are already measured and recorded, but the advanced heating and cooling BTU formulas to determine actual delivered BTU of the equipment and system are not applied. The performance of the system can be rated by dividing delivered BTU into the system design BTU to express system performance in a ratio or a percentage of performance. This performance rating summarizes the report and the result of your commissioning. It also establishes the value of commissioning to the client by providing a benchmark of actual system performance at the time of installation. It can be used to determine if there are installation issues that need to be discovered beyond what is verified during the implementation of the ACCA/RESNET 310 verification. This benchmark can also be of value to the installing contracting should performance issues, such as comfort complaints or high utility usage arise, allowing the builder to look first at possible building defects as the root cause, instead of working backwards from the HVAC installation as is so often the case.
BY combining RESNET/ACCA 310 and ASHRAE 221 in conjunction with OEM commissioning processes for ventilation, dehumidification and controls, HVAC Design Partners can offer a one of a kind Residential Design and Commissioning package that will truly Plan and Implement Occupant Comfort and Indoor Air Quality on every project.
HVAC Design Partners will use its unique partnership with Green Building Consulting to access their extensive rater network to aid in providing true commissioning on the residential systems we design. This allows us to offer our Planned Occupant Comfort and Indoor Air Quality design and commissioning package in most markets across the US.