Combustion Safety Testing at Water Heater

Gap at Return Duct

Insulation Baffle at Attic Eave

Attic Insulation - before

Knee Wall

Infrared Image

Stack Effect in a Building

Duct Blast & Blower Door Test

Attic Knee Walls

Basement Rim Joist - unsealed, no insulation

Cantilevered Floor above Garage

Full Energy Audits

​The purpose of a full energy audit is to determine the energy performance of an existing building and how and where energy is being lost, mainly through air leakage, thermal bypasses, and insufficient insulation. The audit involves a walk-through evaluation and documentation, as well as equipment testing. HVAC equipment and gas appliances are tested for safety and performance, the building and ductwork are tested for airtightness, while individual rooms and zones are tested for pressure differentials and adequate airflow and ventilation. In general, the auditor is looking and testing for the level of “stack effect” in a building. Stack effect is a situation where air infiltrating into a basement or crawlspace (under negative pressure) rises, infiltrates into the conditioned space, rises upward, escapes through air gaps at the ceiling, and flows into the attic, causing heat loss and condensation issues.


The audit typically takes between 4 and 8 hours, depending on the size and complexity of the home and the HVAC systems. The audit is followed by a written audit report that summarizes the findings and proposed solutions. If the homeowner desires, Comfy House can also assemble an estimate for the proposed solutions, and serve as the weatherization services contractor for the proposed work.

 The audit process is conducted in the following order:

 Brief Homeowner Interview

  • The auditor determines comfort, air quality and moisture issues within the home, and reviews the utility bills.


Brief Interior Walk Through with the homeowner

Exterior Walk Around, including measurements and documentation

Extensive Interior Walk Throughevaluation of the home as follows:


  • Interior/Conditioned Space
    • Health/safety issues: mold/mildew, fire hazards, live knob and tube wiring
    • Gas oven safety testing, if applicable
    • Adequate Ventilation: kitchen  and bathroom exhaust fans, dryer vent
    • Walls: construction  type, thickness, type and quality of insulation, quality of air barrier, surface temperatures (via infrared testing)
    • Knee Walls – walls backing up to side attics, check for air gaps and type and quality of insulation
    • Floors: construction type, air gaps, thermal bypasses, surface temperatures
    • Wall Bump Outs/Cantilevered Floors: insulation, air barrier
    • Ceilings: type (flat or vaulted), surface temperatures, thermal bypasses, air gaps
    • Windows and Doors: type, quantity & size, single, double or triple glazing, air sealing, weatherstripping
    • Chimneys: dampers, adequate positive airflow, air gaps
    • Efficiency of Appliances
    • Lighting/light bulbs: incandescent, compact fluorescents, LEDs
    • Water Efficiency: faucet aerators, shower heads, pipe insulation


  • Basement/Crawlspace
    • Foundation Wall: insulation, moisture/mold issues, air gaps, thermal bypasses
    • Rim Joists: air sealing, insulation, air gaps
    • HVAC Equipment: Type (furnace, heat pump, hydronic/boiler, electric radiant, geothermal), fuel type, age, quality


  • Attic Inspection
    • Safety Concerns: live knob and tube wiring, mold/mildew
    • Insulation: type, quality, and R-value based on thickness
    • Ventilation: soffit vents, ridge vents or other type of vents, insulation baffles to assure proper airflow
    • Air Leakage: wall top plates, open wall cavities, open chaseways
    • Attic Access Stair/Hatch: properly insulation and weatherstripping
    • Side Attic Knee Walls: properly insulation, sealed air barrier on attic side, top and bottom blocking


  • Duct System Inspection (if Applicable)
    • Ductwork: type (metal, flex duct), quality, air leakage, insulation, installation issues
    • Supply and Return Registers: quantities, locations, airflow, air sealing, signs of air leakage, pressure differentials between rooms


  • Boiler System Inspection (if Applicable)
    • Radiators: number and size


Combustion Safety Testing

  • Performed on Gas HVAC Equipment and Gas Water Heaters
    • Overall condition, age, proper relief valves and discharge pipes, filters, slope of flue
    • Testing for gas leaks
    • Combustion Appliance Zone (CAZ) Testing: in order to insure that naturally drafting gas equipment drafts adequately in “worst case conditions”
    • Combustion Analyzer Testing of gas equipment for:
      • Spillage (at draft hood)
      • Adequate Draft (at flue)
      • Carbon Monoxide (ambient and at flue)


Blower Door Testing

  • Quantitively determines the airtightness of the home. The conditioned area of the house is depressurized to a specific level, and the flow on the blower door fan needed to reach that depressurization level is measured, in cubic feet per minute (cfm).
  • The higher the cfm reading, the more leakage the house has.
  • Infrared camera testing is conducted during this test to help further determine locations of air leakage in the building


Duct Blaster Testing

  • While the blower door pressurizes the house, the duct blaster test pressurizes the ducts to a specific level to determine total duct leakage to outside the building.
  • The higher the cfm reading, the more leakage in the ducts


Audit Report

  • A typed report in outline form that summarizes the findings of the audit, and follows the findings with proposed solutions


Weatherization Services Proposal

  • If needed, and if requested by the homeowner
  • Lists a scope of work based on the audit report, and total investment