We can save you money by measuring duct leakage with our DUCT BLASTER system!
Air duct leakage can increase heating and cooling costs over 30%. The EPA reported that most American houses have uncontrolled leakage that varies wildly from one day to another, but on-the-average have 70% to 100% of an air change per hour. This “natural” air leakage averages 100% to 200% more than the 35% of an air change per hour recommended for homes by ASHRAE Standard #62-1989 “Ventilation for Acceptable Indoor Air Quality”.The Duct Blaster is a device that uses pressure testing to find the amount and location of air leakage in a duct system. To do the test, we seal all the outlets except for one on the return side of the system (the side that returns stale air to be reconditioned). The Duct Blaster is connected to that last one and then turned on to blow air into the ducts. The air goes through the return ducts to the air handler and then through the supply ducts. If the whole system is very tight, it doesn't take much airflow through the fan to pressurize the ducts. If you have a big leak, like a disconnected plenum or duct, it will be impossible to pressurize the ducts adequately.
The
process yields quantitative results because testing requires two pressure
measurements: one inside the ducts and the other inside the fan. The first
allows the tester to compare results from different systems by always
pressurizing to the same level. The second measures the airflow in the fan when
that level is reached. As mentioned above, tight ducts mean low airflow, and
leaky ducts require lots of airflow.
Pressurizing
only the ducts determines the total leakage. That includes the air that escapes
into the conditioned space and the air that leaks to outside of the building
envelope (i.e., the attic or crawl space). The latter is the most important part
because you derive no benefit from it. To separate it from the total leakage, we
will pressurize the house to same level as the ducts with the Blower Door. Then,
when the Duct Blaster brings the ducts up to the required pressure, none
will leak to the inside of the house because it's at the same pressure as the
ducts. The fan only has to blow enough air in to make up for the leakage to the
outside, and that's the amount that's important.
In
a tight air distribution system, the leakage to the outside (in cubic feet per
minute, or cfm) will be 5% or less of the square footage of the house. Most new
installations start at about 15 to 20%...and go downhill from there. At those
rates, a third of the heating and cooling bills could be a direct result of
duct leakage.
Contact our sales
department a let us get you scheduled for this money saving analysis on your
duct system!