03 Dec 2015
Metal Ducts: Old andWithout Seals
Way back between 1950 and 1980, people were taking energyefficiency for granted, because energy was INEXPENSIVE. Installers didn't makean extra effort to seal hvac website the metal ducts they were working on.
Sections of metal ducts were just slid into each other, andwere set into place with a few screws. The ducts were then wrapped withinsulation to prevent sweating and condensation, but not to insulate them andmake them energy efficient.
If hvac website the ductwork is not sealed it leaks. Not sealing ductworkwould be like putting copper pipes together for plumbing without SOLDERING thejoints.
Imagine an air conditioning duct as a long, hole-riddengarden hose. The pressurized water (or air in an air conditioning duct) willleak out of all the holes BEFORE it gets to the end of the hose. You get avery, very small amount of water out of hvac the hose's end since much of the waterhas already leaked out. That's what happens with air conditioning ducts thathave more than 40% leakage -- most of the HOT or COLD air has escaped out ofthe ductwork hvac website and into the attic, where it's not supposed to be.
Older metal ducts are very prone to leakage. Many studieshave proven that there's a direct link between hvac website the duct system's age and ductleakage percentage. Also, a duct wrapped with insulation is akin to wrapping aleaking pipe with a rag to stop the leak. The insulation does virtually NOTHINGto lessen duct leakage since the air is under pressure.
Leaking airconditioning -- Not good!
Nobody wants higher energy bills, but leaky ducts createnegative pressure, increasing energy costs. If there were 20% leakage, the sameamount of air would need to enter the house through whatever means, be itthrough the windows, the doors, can lights, and any other "holes" inthe house. Outside air is always dirty, with dust, pollen, and humidity -- thisair will enter a home with leaky ducts. You'll know that outside air gets intothe home when there's dust on windowsills and carpet stains around baseboards.
A few air-conditioning companies cash in on leaky ducts byoffering a new air conditioning unit for thousands of dollars instead ofsealing or replacing leaky ductwork. The latter costs only a fraction of theprice of a new air conditioner.