HVAC Contractor Credentialing Frequently Asked Questions
It is best to consult the inspector. The inspector interprets the CODE, and it’s ultimately up to him/her how the CODE is enforced.
The supply and return plenums immediately outside the air conditioner or heat pump air handler cabinet are the preferred locations. If these are NOT accessible, the front, back, left or right side of the cabinet itself may be used.
Room pressure balancing is the process of testing the home for pressure differentials while the HVAC equipment is operating. This is done in every room that is conditioned by closing all the interior doors and measuring the pressure difference across each door created by the action.
When air is supplied to a room but cannot escape, the room experiences a positive pressure. When a positive pressure is created in the room, an equally negative pressure is created somewhere else, such as the hallway/main body where the central return is located.
This negative pressure difference can pull air from the outdoors into the home, which can have undesirable contaminates, like radon, particulates, humidity, chimney smoke, garage smells, etc. If a house with atmospherically vented gas appliances were to experience a high negative pressure, those gas appliances may experience inadequate or total failure to vent combustion gases out of the home. Therefore, gasses may “spill” into the living space.
There are two goals of balancing the pressure off a room:
- Keep the house at as neutral a pressure as possible. This keeps air from an unknown source from moving into the house;
- Help the combustion appliances exhaust the products of combustion as directly and quickly to the outdoors as possible.
There are four methods that can be used to relieve room air pressure and have a house that is pressure balanced to pass ENERGY STAR program requirements:
- The door undercuts above the finished floor
- There are dedicated returns in each room
- There are jumper ducts in each room
- There are transfer grills in each room
We highly recommend that you use at least two methods in conjunction for the best results while maintaining the privacy of the space. First, be sure to know the supply CFM to each individual room. Using the pressure balancing chart in the technical guide, find your CFM and the corresponding required net-free area for pressure relief. After finding the pressure relief number, find your balancing type in the technical guide.
Notify your rater and builder as soon as possible. Ideally, this should be done before the equipment is installed.
No, but they are recommended in this program to help with air balancing.
The best time to get involved in an ENERGY STAR project is before you even break ground on the home’s foundation. To meet the ENERGY STAR requirements in the most cost-effective way, it’s critical to include all players involved in the project from the get–go. Schedule a kick–off meeting before any dirt is moved and invite any contractors or specialists working on the project. This may include the designer, installers, service staff, electrician, framer, insulator, builder and rater. Advanced Energy strongly recommends that all of these team members participate in a meeting to discuss the overall game plan and specific roles for each project. Some topics to discuss include:
- What type of heating and cooling system(s) will be used?
- What ventilation system will be used?
- Where will the HVAC systems be located?
- What are the minimum requirements for climate zone and equipment type?
- Where will the ducts be installed?
- Will we need to pressure test ducts before and during final certification testing?
- What kind of filtration system will be installed?
- Where will the filter be located?
- If the filter is located in the attic, the builder must install pull down stairs to the attic, no scuttle hole is allowed.
- Will we use an ERV or HRV? Where will it be located and how will it be maintained?
- Who is responsible for bathroom exhaust fans?
- Each exhaust fan should be rated to at least 70 CFM to get 50 CFM on the test–out.
- They must be rated at no more than three sones.
- The fan must be installed so the duct can exit the structure with as few turns as possible.
- How will we prepare for pressure balancing of the rooms?
- For transfer grills, under-cut doors and bypass duct(s), we recommend using at least two of these methods in conjunction.
The following items need to be sent:
- Manuals J, D and S
- A completed HVAC Design Report
- A design temperature request form if temperatures if any of the following is true;
- Heating indoor design temperature is not 70 degrees Fahrenheit
- Cooling indoor design temperature is not 75 degrees Fahrenheit
- Heating Outdoor temperature is below the ENERGY STAR County level design temperature
- Cooling Outdoor temperature is above the ENERGY STAR County level design temperature
Here are a few recommendations for performing rough-ins:
- Install AH and all duct work; make sure all joints are sealed with bucket mastic.
- If using dedicated returns, jumper ducts or transfer grills, frame these in now.
- Duct work will be reviewed and have to match up to the manual D duct plan, so be sure your installers follow the plan and only the plan. You cannot have excess duct work or unnecessary turns. Flex must be supported every 4 feet and cannot turn greater than 90 degrees and can have no kinks or be crushed into duct chases.
- Do not use tape to air seal. Mastic must be used. Splicing in duct sections is acceptable, just be sure to use a splicing collar and air seal all the inner liner connections with bucket mastic.
- Don’t forget to mastic the inside of boots and insulate them properly. Also air sealing the connection between the boot and subfloor with mastic is easier now than with the finished floor down.
Here are a few recommendations for performing trim–outs:
- Install outdoor unit and pressure test the line set if applicable.
- Install the thermostat and outdoor sensor if applicable.
- Install all supply, return and transfer grills. Seal to the gypsum at this time.
Here are a few recommendations for performing duct testing:
- Install outdoor unit and pressure test the line set if applicable.
- Duct testing must be performed at final for the following reasons:
- Insulators, framers or sheet rockers may puncture ducts during construction, so they must be tested at final.
- If you are not be able to get to duct connections after the gypsum is installed, we highly recommend you test before gypsum, so you know you won’t have to do it later if the ducts fail on the final.
- Balancing dampers are not required, but you must be able to balance your airflow. If the duct will be inaccessible, opposed blade dampers are acceptable at the boot.
Many variables are involved in analyzing costs and benefits in this scenario. However, knowing and understanding the importance of key aspects of air flow testing can help keep the costs as low as possible. Three important aspects include:
- System Components:
- How many ducts are there to test?
- Are the supply and return grilles reachable without the aid of a ladder or other tool?
- Can the dampers be easily accessed?
- Labor Costs:
- How many employees will be involved during testing?
- How accurate, efficient and knowledgeable are the operators of their test equipment?
- Call backs:
- How accurate is the test equipment?
- Provided below are acceptable test methods for fulfilling the design criteria (according to ACCA Standard 5):
- OEM CFM/static pressure drop coil table method using a manometer and probe to determine the static pressure drop across a cooling coil, furnace, or fan coil unit and compare with OEM values;
- Traversing using a manometer and probe, or an anemometer (e.g., hot wire, rotary style) or other methods per ACCA, AABC, ASHRAE, ASTM, NEBB, SMACNA, or TABB procedures;
- Flow grid measurement method;
- Pressure matching method10; or
- The temperature rise method (for heating only: gas or oil furnace, electric resistance heat, geothermal and water source heat pump) to verify proper airflow through the heat exchanger or heater elements [NOTE: It is not acceptable to use the temperature rise method to determine cooling airflow over the indoor coil].
- Additionally, follow these two simple steps to save time and money:
- Accessibility plays a significant role in system commissioning. While designing the system, make sure that you design access points for the parts of the system that will require testing during startup.
- Since a Rater will test the duct work a second time using the static pressure method, have the installers or shop personnel in charge of constructing the duct to drill two holes for pressure measurements.
No. The affiliate could become credentialed through our program if they meet all of the requirements listed on our application including being a licensed mechanical contractor (in states that require a license), having valid general liability insurance, having a valid EPA refrigerant certification, and also by meeting all other application and onboarding requirements. Our recommendation is that the affiliate work with a licensed HVAC Contractor who is credentialed or can become credentialed in order to support their ENERGY STAR Certified New Homes program builds.
Per ACCA and RESNET standards, the following devices can be used: