The assessment and development of ducts have a logical order of steps.
- Determine whether over 30% of the ducts are present outside of the conditioned space
Only duct systems located over 30% outside of conditioned space are qualified for duct sealing.
To know if a duct system is over 30% outside of the conditioned space, the total length of the duct system and the length of the system in conditioned space can be measured with tape. If the length of the duct in conditioned space is less than 50% of the total length, the duct system is entitled to duct sealing.
- Assess the ducts visually for air leakage/condition and know whether duct sealing is required
Only duct systems with an assessed leakage grouping of “some observable leaks” or “significant leaks” are qualified for duct sealing.
Only ductwork having properly attached links and whose airflow has not been conceded due to crushed ducts.
NOTE: If the duct system has crushed or improperly attached/disconnected ducts to the point that the Energy Specialist thinks that system cannot be sufficiently sealed without first fixing ductwork, then talk to the customer to have a program-approved list of HVAC contractors to assess the duct systems state.
- Know if the system airflow complies with related program requirements
Only systems having airflow CFM falling within program suggested airflow rates are qualified for duct sealing.
Only Duct systems with available filter slots or single return grilles will have its’ airflow measured using the True Flow Plates
Duct airflow can be measured using the Temperature Rise method if the system is HEATING ONLY.
All systems with COOLING must have a TRUE-FLOW test to qualify to be duct sealed.
Further duct systems that should not be assessed for duct sealing possibilities are as follows:
- Duct board systems
- High-velocity systems
- Systems insulated with the radiant bubble wrap unless the bubble wrap is believed by the energy specialist to have an effective R-value of under R-3. In which case, the bubble wrap would be detached and the ducts would be insulated to R-8.
- Any repair work necessitating the use of HVAC industry tools and materials other than a cable tie (Zip Tie) tensioner. It will be referred to program approved list of HVAC contractors.