Ventilation

Ventilation in a home is important for controlling humidity, temperature, and providing adequate healthy indoor air. Older houses were not “tight.” Air exchanges took place through the openings inherent in the building’s envelope. Passive venting kept attic temperatures and humidity seasonally appropriate. New, much tighter, well-insulated buildings must use mechanical means to achieve indoor air quality requirements. Air-to-Air and Heat Recovery Ventilators (HRV), as well as Energy Recovery Ventilators (ERV) are used to maintain a healthy interior environment without running up HVAC operating costs.

Inspect for the basics: does the attic have balanced ventilation, e.g. ridge and soffit vents? Power vents should be tested if possible. “Whole house” fans must not be on automatic controls. Are full bathrooms and cooking areas provided with quiet, operative ventilators in good condition? Do all vents exhaust to the exterior? Are all exterior vent terminations pest-entry proof? We only inspect HRV and ERV units with the homeowner controls. Look for damage, improperly-installed filters, etc.

The fan exhausts to the attic instead of the exterior. This will increase moisture levels and mold/mildew issues. Reroute the discharge to the exterior away from the structure.

The fan exhausts to the crawl space instead of the exterior. This will increase moisture levels and mold/mildew issues. Reroute the discharge to the exterior away from the structure.

The fan exhausts to the garage instead of the exterior. This will increase moisture levels and mold/mildew issues. Reroute the discharge to the exterior away from the structure.

The exhaust vent is too close to the outside grade. This can allow snow or debris to block the vent. Raise the vent to at least 1′ above the grade.

The exhaust fan exterior hood is missing or damaged. This permits pest intrusion. Replace the exterior hood.

The exhaust fan exterior hood is blocked. This affects proper operation and is a safety concern. Clear the hood.

The exhaust fan duct is damaged. This permits moisture into the house. Repair or replace the duct.

The whole house fan is inoperative. Repair or replace the fan for proper function.

The whole house fan protective shroud is missing. This is a safety hazard. Install or replace the shroud.

The whole house fan has been installed in an unworkmanlike manner. This is a safety and reliability concern. Reinstall the fan.

There is a timer or  thermostatically-controlled whole house fan in the attic. This is no longer permitted. The fan can depressurize the house and cause combustion appliances to backdraft if it operates without windows open to provide make-up air. Remove the fan’s automatic control so that manual operation is required.

There are blocked attic ridge vents. This permits heat and moisture buildup. Clear the vents.

There are blocked attic gable vents. This permits heat and moisture buildup. Clear the vents.

There are blocked attic roof vents. This permits heat and moisture buildup. Clear the vents.

The exterior soffit vent screens have been painted over. This makes them ineffective, and permits heat and moisture buildup. Clear or replace the vent screens.

There are missing soffit vent baffles in the attic. This permits insulation to block the vents and cause heat and moisture buildup. Repair or replace the baffles.

There is damaged attic vent screening. This permits animal and pest entry. Replace the screening.

There is damaged crawl space vent screening. This permits animal and pest entry. Replace the screening.