A young couple bought their first home last year, in Barrington, IL. The partially renovated house, built in 1967, had space for their new baby and all his gear plus plenty of room for future needs. With a "newer" HVAC system, the first time-homebuyers felt reassured that their furnace would be reliable and sufficient. However, the homeowners soon noticed the second floor was always too hot or too cold and would not maintain the same temperature as the rest of the house. Their new-born son's room was of particular concern and prompted an urgent investigation into the uneven room temperatures, poor air flow and the indoor air quality in the home. 

Homeowner Complaint

The new homeowners told Priority Energy, “We have two HVAC systems; one for the upstairs and one for the basement and first floor.  When we set the thermostat to 72° upstairs, the temperature on the second floor will not cool below 79° on hot days and is just not comfortable.  When we set the temperature on the first floor it easily reaches 72°, but then the basement is freezing.”

Findings and Diagnosis 

This 4200 square foot home had 2 HVAC systems, with the mechanical equipment for both systems located in the basement.  Air flow to the first floor was good, but the amount and speed of the air from the upstairs registers was weak or  nonexistent.

Priority Energy measured the duct leakage and found a combined 415 CFM of air leakage, or the equivalent of a 77 square inch hole in the ductwork, in addition to a completely disconnected duct run in the basement ceiling (which equals approximately another 100 CFM of leakage). Duct leakage this high severely impacts the performance and efficiency of the HVAC system and will make indoor temperature settings hard to maintain. Indoor air quality could also be compromised due to dusty, damp air getting pulled in through the leaks as the ductwork runs through the basement and behind walls.  

It was not surprising this couple was having trouble cooling their second floor; we removed over 200 CFM of leakage with Aeroseal and >=100 CFM by identifying and reconnecting the broken duct in the basement (it was supplying the 2nd floor) on the 2nd floor system alone.  The combined 300 CFM means that over one third of the total airflow going to the 2nd floor, or over 1/3 of their total cooling capacity, was never reaching their second floor.  

Same goes for the basement; everyone thinks their basements are cool because they’re below grade; when in reality it is often because their ductwork is leaking all (or most) of their cooling into the lower level.  In this homeowner’s case we removed nearly 1 Ton of leakage from their basement duct work – this is more than their basement needs for cooling in the first place.

Similar comfort complaints, especially when mechanical systems are installed in basements, are common. Duct leaks can make it nearly impossible to get even, stable temperatures throughout a home, and heating and cooling systems are forced to work overtime which can lead to high humidity and expensive colling costs. 

Solution and Results 

Having seen situations like this before, Priority Energy knew duct sealing with Aeroseal would solve the problem. Aeroseal’s duct sealing process is the most effective way to permanently seal cracks and holes without breaking through walls.  Technicians plugged all the duct register openings and connected the tubing, sealant, and computer to the furnace opening. The Aeroseal computer tracks the duct sealing progress and is monitored continuously during the aerosol injection. Precise pre- and post- duct sealing measurements are recorded, and a report is generated.  

Pre- Aeroseal Duct Leakage: 415 CFM or 77” hole (with a disconnected duct line)

Post – Aeroseal Duct Leakage: 36 CFM or 7” hole (after reconnecting and sealing ducts)

Final Duct Sealing Results came to a >94% reduction in leakage. 

“It was great to see a 94% improvement; we felt a big difference in air flow upstairs right away. The second floor has been able to maintain a 72-73° setpoint during the middle of the hottest days.  We feel better knowing the air is healthier for the baby, too. The Priority Energy technicians were great and the process was fast.” said the proud new parents.