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Winnetka case study

A master bedroom that would not warm up in winter

Hot and cold rooms throughout, with a master bedroom that stayed cold through the heating season. What we measured, what we corrected, and what changed.

The comfort problem

Hot and cold rooms throughout, with a master bedroom that stayed cold through the heating season.

What we measured

Static pressure
1.15
Airflow by duct sizing
997 CFM
Airflow required
2,000 CFM
Return duct capacity
542 CFM
Master bedroom airflow
100 CFM

What the numbers told us

  • The supply plenum and fittings were restrictive, and the return was worse.
  • Duct sizing capped delivery at 997 CFM against a 2,000 CFM requirement.
  • The return alone could carry 542 CFM — roughly a quarter of what the system needed to breathe.
  • A master bedroom receiving 100 CFM was the symptom the homeowner actually felt.

What we corrected

  • New supply fittings
  • New return fittings and drop
  • Less restrictive horizontal filter
  • Air balancing and air upgrades

What we measured afterwards

Static pressure
0.76
Master bedroom airflow
216 CFM

The restrictive supply plenum and undersized return were the limit, not the equipment. Master bedroom airflow more than doubled.

Before and after

Photographs from this job, supplied by GV's.

Before

The original lineset and supply ductwork before the work.
Before: The original lineset and supply ductwork before the work.
The restrictive original fittings above the air handler.
Before: The restrictive original fittings above the air handler.
The furnace as we found it, with the original plenum in place.
Before: The furnace as we found it, with the original plenum in place.

After

The new supply plenum and fittings after the work.
After: The new supply plenum and fittings after the work.
The rebuilt return drop and less restrictive horizontal filter.
After: The rebuilt return drop and less restrictive horizontal filter.

Identified by city only — no names, no addresses, nothing that identifies the household. More on why we publish the readings.

If this sounds like your house, call our team at (847) 729-9190 or request an assessment.