9484 Chesapeake Dr. Ste. 806 San Diego,CA 92123 Serving San Diego Since 1991 info@airplusmechanical.com


Ductwork San Diego

Is It Time to Replace the Ductwork in Your San Diego Home?

Replacing your old, leaky inefficient ductwork may be one of the best things you can do to improve efficiency and comfort in their home.


Typically, when your home is over 25 years old and your ductwork is in the attic (most homes in San Diego) there is a big chance that it’s time to replace. Think of your house as one big refrigerator. Leaky ducts are like leaving the door open.

Duct leakage is typically measured as a percentage. If you have 20% duct leakage this means that approximately 20% of the warm or cool air you are spending money on is being pushed through of the ducts and into the attic. Or, duct leakage can also mean you are sucking warm or cool attic air through the duct system on the return side of the forced air unit. 2-5% duct leakage on newer homes is ideal, older homes (especially with metal ducts) it is not uncommon to see duct leakage over 40%.

Why do older San Diego homes have such bad leaky ducts? Back in the era between about 1950-1980 folks were not concerned about energy efficiency. Energy was inexpensive, so installers usually didn’t bother to take the extra time or money to seal the ducts. For metal ducts this meant sliding two sections of duct together and using screws to connect them. Then, they would wrap the ducts with insulation to keep them from sweating or condensing moisture, not primarily to insulate them.

It’s not that the ducts started leaking; they were never sealed to begin with. If you have ever done some plumbing, this would be like connecting copper pipe together and not using solder on the joints.

Think of air conditioning duct as a long garden hose with a hundred holes in it. Since water (or air in the ducts) is under pressure, the water will leak out of all hundred holes before it gets to the end. Whatever does not leak out of the holes along the way is what ends up coming out of the end where you want it. Air conditioning ducts are exactly the same and it’s pretty common to end up with only 50-75% of the air where we need it.

Older ducts – especially metal ducts are notorious for leaking. Studies show that there is generally a direct correlation between the age of the duct system and the percentage of duct leakage. Additionally, wrapping a duct with insulation does virtually NOTHING to reduce duct leakage just like wrapping a leaky pipe with a rag won’t stop a water leak.

At Air Plus Heating & Cooling, we use R-6 foilback flex ducting and use duct sealer on all penetrations. This ensures optimal efficiency.

To schedule an inspection for ductwork repair/replacement, call:

(858) 505-8711 or (619) 276-8165