Duct Systems | Alabama Power

Duct Systems


A properly installed duct system helps you live comfortably while using energy efficiently

The control and distribution of heated and cooled air in your home is carried out by the duct system. Significant amounts of heated and cooled air can be lost through leaks in ductwork. A properly installed duct system helps you live comfortably while using energy efficiently.


The facts

Locating ductwork during construction in conditioned versus unconditioned areas of the home can result in savings of more than 20% in heating and cooling costs.

Repairing duct leaks in existing homes can result in heating and cooling savings of as much as 30%.  That's a big savings for a problem that's inexpensive to locate and repair.


Installing a duct system

The duct system should be designed by an accredited professional using industry-recognized procedures.

We recommend the following insulation specifications to ensure high efficiency and low operating costs:

  • Check local codes for duct insulation R - Value. If construction design permits, install ducts inside the conditioned area.
  • Seal all joints with duct mastic, duct mastic tape or the equivalent.
  • Insulate and caulk/mastic all seams of insulating materials used to line the return-air plenum to avoid drawing air in from the attic or unconditioned areas.

Upgrading your home's duct system

Look for ductwork leaks in the air-handling unit and between the following components:

  • individual sections of ductwork
  • ductwork and boots
  • registers
  • ductwork and plenums
  • ductwork and return-air chamber
  • air-handling unit and plenums
  • support platform and return-air chamber

We recommend the following insulation specifications if you are upgrading your duct system.

  1. Supply and return ducts should be insulated according to local and state codes.
  2. Mastic or seal all joints between ducts, supply plenum and heat pump and insulate against heat transfer.
  3. Seal heater closet paying special attention to pipes and wires that pass through walls.
  4. Seal off heater closet from the attic, if using a totally electric heat pump, so the system can't draw unconditioned air from that area.
  5. Upgrade attic insulation to R-30 or R-38.