Tools to Improve Ventilation

Posted on: August 18, 2021

Consider using some or all of the following tools to improve ventilation:

Increase the introduction of outdoor air:

Open outdoor air dampers beyond minimum settings to reduce or eliminate HVAC air recirculation. In mild weather, this will not affect thermal comfort or humidity.

Open windows and doors, when weather conditions allow, to increase outdoor air flow. Do not open windows and doors if doing so poses a safety or health risk (e.g., risk of falling, triggering asthma symptoms) to occupants in the building.

Even a slightly open window can introduce beneficial outdoor air.

Use fans to increase the effectiveness of open windows:

To safely achieve this, fan placement is important and will vary based on room configuration. One strategy is to use a window fan, placed safely and securely in a window, to exhaust room air to the outdoors. This will help draw outdoor air into the room via other open windows and doors without generating strong room air currents. Similar results can be established in larger facilities using other fan systems, such as gable fans and roof ventilators.

Ensure ventilation systems operate properly and provide acceptable indoor air quality for the current occupancy level for each space.

Rebalance or adjust HVAC systems to increase total airflow to occupied spaces when possible.

In homes and buildings where the HVAC fan operation can be controlled at the thermostat, set the fan to the “on” position instead of “auto,” which will operate the fan continuously.

Improve central air filtration:

Increase air filtration to as high as possible without significantly reducing design airflow. Increased filtration efficiency is especially helpful when enhanced outdoor air delivery options are limited.

Make sure air filters are properly sized and within their recommended service life.

Inspect filter housing and racks to ensure appropriate filter fit and minimize air that flows around, instead of through, the filter.

Consider investing in an air purifier and/or portable high-efficiency particulate air (HEPA) fan to enhance air cleaning (especially in higher risk areas such as a nurse’s office or areas frequently inhabited by people with a higher likelihood of having COVID-19 and/or an increased risk of getting COVID-19).

Consider using ultraviolet germicidal irradiation (UVGI) as a supplemental treatment to inactivate SARS-CoV-2, especially if options for increasing room ventilation and filtration are limited. Upper-room UVGI systems can be used to provide air cleaning within occupied spaces, and in-duct UVGI systems can help enhance air cleaning inside central ventilation systems.

Estimated cost of implementing these tools;

$0 (no cost): opening windows;

$100 (approximately): using fans to increase effectiveness of open windows;

$500 (approximately): adding air purifier

Note: Tools are summarised based on the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Guidance for Building Operations During the COVID-19 Pandemic.