Energy Efficiency Tips


  • Duct seams need to be mechanically fastened (using sheetmetal screws for galvanized ducts and compression straps for flex duct) before being sealed.
  • For sealing most duct leaks, mastic works better than tape.
  • When applying mastic - "Plug, don't paint and thick as a nickel."

Studies indicate that duct leakage can account for as much as 25% of total house energy loss.

It's important to prioritize duct sealing efforts so that the most important leaks are addressed first:

  • In existing homes, it's surprisingly common to find disconnected duct components - takeoffs that are coming loose from ducts or ducts disconnected from register boots - in attics or basements. Such disconnected ducts can waste tremendous amounts of energy.
  • Leaks connected to the outdoors are more important than leaks inside the home's thermal envelope.
  • Holes that see high pressures - in other words, holes near the air handler - are more important than distant holes that see relatively low pressures.
  • Most furnaces have many bad leaks close to the blower fan, including leaks in the furnace jacket seams, leaks between the furnace and the plenums, and leaks between the duct takeoffs and the plenums.
  • Supply system leaks waste more energy than return system leaks.
  • Seal all seams on trunks with mastic or tape.
  • Seal all seams on hard pipe with mastic or tape.
  • Seal all seams on elbows with mastic.

Did You Know

Did You Know

The average home has enough air leakage to add up to a two-foot-square hole. That's like leaving a medium-sized window open 24 hours a day.

You can save 5%-30% on your energy bill by making upgrades to your HVAC System and Duct Work.

Studies indicate that duct leakage can account for as much as 25% of total house energy loss.

Duct leakage can prevent heating and cooling systems from doing their jobs properly, resulting in hot or cold rooms, and humidity problems.

Duct leaks can create air quality problems by pulling pollutants and irritants directly into the house.

Tips for HVAC Companies to obtain a passing system:

  1. Use mastic (*Remember - Plug, don't paint and thick as a nickel).
  2. Pay special attention to seal the areas closest to the Air Handler (plenum).
  3. Apply mastic around all collars - then fasten flex duct using zip ties.
  4. Seal all seams on elbows (again, use mastic for this).
  5. Pay attention to the corners of trunks/ duct where slip & drive is being used (those holes add up quick).
  6. Mastic all seams on hard pipe **especially the seams inside walls where drywall will be covering them up****
  7. Silicone or mastic around any boots that are coming up through the flooring to the sub-floor. Same thing goes with the returns.
  8. Pan-out all returns that are running through bays.