System & Financial Parameters
$10,000
Full replacement unit, labor, and permits.
$2,500
Gas, heat pump, or electric heating & cooling total.
$500
Contractor claim: "Spending $10k to save $500/yr takes 20 years to break even."
25%
Unsealed ducts routinely lose 20% to 30% of conditioned air before reaching rooms.
$3,000
Field rule: $3,000+ broken compressor/exchanger tips the math toward replacement.
Ceiling & Room Volume Sizing
18,000 ft³
Contractor wisdom: "Always use cubic feet, not square feet; standard sq ft ignores high ceilings."
Calculated Audit & Payback Model
Baseline StatePayback Period
20.0 yrs
Net equipment cost / annual savings
Annual Duct Waste Loss
$625 /yr
25% of $2,500 bill wasted in attics/crawlspaces
Duct Sealing Savings Range
$375 - $625
15% to 25% utility bill reduction
20-Year Net Cashflow
$0
$10,000 saved minus $10,000 cost
Heated & Conditioned Air Distribution
25% Duct Loss
Contractor Field Directives (30 Years Experience)
- The Payback Rule: Spending $10k to save $500/year is generally poor ROI unless forced by unrepairable components or cracked heat exchangers.
- The Duct Seal Priority: Homes frequently cut heating bills by 15% to 25% purely from mastic/tape duct sealing before touching equipment.
- Sizing by Volume: Always size blower cfm and ductwork using cubic feet (accounting for vaulted ceilings) rather than raw square footage to prevent short cycling.
- Sensory & Thermometer Verification: Infrared no-contact sensors and technician senses (sound, temperature delta) yield truthful diagnostic validation over marketing claims.