HERS Rating

Change-out Flow Charts       E-Mail       Letter to Homeowners

As of October 1, 2005, you must have your home or office ducts tested for leaks when you have a central air conditioner or furnace installed or replaced. Ducts that leak 15 % or more must be repaired to reduce the leaks. After your contractor tests, seals the ducts, and fills out the proper forms, you choose an approved third-party HERS Rater to check and make sure the duct sealing and duct testing was done properly.

    Duct sealing is not required in the following situations:
  1. When homes (does not apply to nonresidential structures) are in specific coastal climates
  2. When systems have less than 40 feet of ductwork in unconditioned spaces like attics, garages, crawlspaces, basements or outside the building.
  3. When ducts are constructed, insulated or sealed with asbestos.
There also are specific alternatives that allow high efficiency equipment and added duct insulation to be installed instead of fixing duct leaks.

The greatest energy use in California homes is for central air conditioning and heating.
Most homes with central air conditioning and heating systems have ducts that were never properly sealed . The average home's ducts leak around 30 % of the conditioned air outside the home. These leaks are taking money straight out of your pocketbook. Properly sealed ducts will lower your energy bills and reduce pollution inside your home.

What does my energy bill pay for?


HERS raters are special inspectors certified by the California Energy Commission (CEC) to rate homes in California according to the Home Energy Rating System (HERS). These ratings include field verification and diagnostic testing to determine energy efficiency levels among homes tested for duct efficiency, envelope leakage and building insulation for compliance with current building efficiency standards. You can locate a HERS rater at HERSRater.net

Ducts are a system of tubes that distribute conditioned air to rooms throughout a structure. Sealed ducts have properly installed joints and connections to minimize leakage air. Air leaks cannot be seen, and so diagnostic testing verifies leakage. The use of a fog machine in conjunction with the Duct Blaster¨ can help to locate them. These leaks can then be addressed by using approved tapes, mastics, and mechanical fasteners.

What is a "Duct Blaster®"?
A Duct Blaster® is a tool used to test the air leakage rate of forced air duct systems. The equipment consists of a calibrated fan, tape to temporarily seal all the registers, flexible duct to connect the fan to the central return of the duct system; and a digital meter to measure fan flow and duct pressure. Duct leakage is measured by pressurizing the duct system and precisely measuring the fan flow and duct pressure. Duct leakage measurements are used to diagnose leakage problems and certify the quality of duct system installation.

Duct Leakage Testing

Duct leakage measurements are used to diagnose duct leakage problems and verify the quality of your duct system. HERS Raters can use either a Duct Blaster® or a blower door to measure how leaky, or tight, a heating or cooling system is.

Leaky ducts can reduce the efficiency of a forced-air heating or cooling system by 20 to 40+%. These leaks can make your home uncomfortable and unhealthy. Leaks in return ducts can pull pollutants into your home from your attic, basement or garage. Leaky supply ducts can negatively pressurize the house and cause drafts or moisture problems.

Sealing leaky ducts will improve both the efficiency and performance of your heating and cooling system. Leaky ducts make your heating and cooling system work longer and harder to keep you comfortable. Homeowners who have had their leaky ducts sealed have noticed a decrease in their monthly energy bills and an increase in comfort.


HERS Rating,
Brought to you by
D&H Climate Control ™
19014 Canyon Meadows Drive,
Trabuco Canyon   California  92679
Tel: 949.766.8925   Fax: 949.766.8925
C-20 Lic. # 655520
HERS Rater Certification #: CC2004475