Duct leakage can account for as much as 20 percent of the energy consumed by an average residence. It’s a major source of high utility costs for Fresno homeowners. California’s Home Energy Rating System (HERS) requires duct certification after a new central air conditioner or furnace is installed. The requirement has been extended to apply to change-out of individual components, as well, such as an air-handler, coil, or installation of more than 40 feet of ductwork. After the installation, an inspection must be carried out by a professional HVAC contractor using industry-standard equipment and practices. If leakage greater than 15 percent of system airflow is determined, duct sealing is required.
Following the duct sealing work, the homeowner can choose from a list of approved third-party HERS raters to certify that the process was completed correctly. HERS raters are trained and certified by the California Energy Commission to rate homes according to state specifications.
For the average residence, a HERS duct certification can be completed in approximately two hours. The sequence consists of the following:
- A visual inspection of the ducts in conducted to identify any obvious trouble spots.
- Calculation of acceptable leakage rate is completed, using system specifications.
- All supply vents are sealed off and a Duct Blaster pressurization fan is connected to the ductwork.
- The Duct Blaster pressurizes the system until the correct pressure within the ducts is reached.
- A digital manometer attached to the Duct Blaster displays the Cubic Feet per Minute of leakage.
- If leakage exceeds the 15 percent standard, corrective steps will be recommended. These may include simple remedies such as sealing a leaky connection or a flexible hose that has become disconnected.
Duct segments or fittings that are corroded or damaged may be replaced individually. Sheet metal fabrication services offered by HVAC contractors can provide spans of ductwork and custom fittings to restore ductwork and eliminate leakage.
For more than 40 years, Donald P. Dick Air Conditioning has provided Fresno area residents with experienced sales and state-of-the-art HVAC technology. We offer HERS duct certification as well as a full-service sheet metal fabrication shop for duct repair.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about duct certification and other HVAC topics, download our free Home Comfort Resource guide.