Calculating Potential Savings from Audit Findings

Accurate savings calculations help prioritize improvements and justify investments. While professional software provides precise calculations, DIY auditors can estimate savings using simplified methodologies based on building science principles.

Heating and Cooling Loss Calculations

Air Leakage Savings Estimate:

Air infiltration costs can be estimated using: Annual Air Leakage Cost = House Volume × Air Changes per Hour × 0.018 × Heating/Cooling Degree Days × Fuel Cost per BTU

For a 2,000 sq ft home with 8-foot ceilings (16,000 cubic feet): - Moderate air leakage (0.5 ACH): $240-480 annually - High air leakage (1.0 ACH): $480-960 annually - Air sealing reducing leakage by 50%: $120-480 in annual savings

Insulation Improvement Savings:

Calculate heat loss through building components: Heat Loss (BTU/hour) = Area × Temperature Difference ÷ R-Value

Upgrading 1,000 sq ft of attic insulation from R-11 to R-49: - Before: 1,000 × 40°F ÷ 11 = 3,636 BTU/hour loss - After: 1,000 × 40°F ÷ 49 = 816 BTU/hour loss - Reduction: 2,820 BTU/hour × heating hours × fuel cost = annual savings

Equipment Efficiency Calculations

HVAC Upgrade Savings:

Compare annual fuel consumption between old and new equipment: New Annual Cost = (Old Annual Cost × Old AFUE) ÷ New AFUE

Replacing 60% efficient furnace with 90% efficient model: - Old annual heating cost: $1,200 - New annual cost: $1,200 × 0.60 ÷ 0.90 = $800 - Annual savings: $400

Water Heater Efficiency Improvements:

Water heating typically accounts for 18% of energy use: - Insulation blanket savings: 5-10% ($25-50 annually for average home) - Temperature reduction (140°F to 120°F): 10-15% savings - Low-flow fixtures: 10-25% hot water usage reduction - Timer installation: 5-12% savings on electric units

Appliance and Lighting Savings

LED Lighting Conversion:

Calculate savings for each replaced bulb: Annual Savings = (Old Wattage - New Wattage) × Hours Used × Days per Year × Electricity Rate ÷ 1,000

Replacing 60W incandescent with 9W LED used 3 hours daily: (60 - 9) × 3 × 365 × $0.13 ÷ 1,000 = $7.26 annual savings per bulb

Appliance Replacement Analysis:

Compare Energy Guide labels for annual consumption: - Refrigerator upgrade: $50-150 annual savings typical - Washing machine: $25-75 annual savings - Dishwasher: $15-40 annual savings - Consider remaining useful life and replacement timing