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How COVID has Changed HVAC Guidelines in Canada

Posted on December 2, 2021
by Appleby Systems

With the advent of COVID-19, Canadians become much more aware that poor ventilation is a contributor to the spread of airborne illnesses. COVID-19 specifically can spread through the droplets that we breathe, cough or sneeze out. Being in an enclosed space, particularly one with poor ventilation, can increase your likelihood of catching or spreading COVID-19. The same can be said of other airborne illnesses. 

According to the Public Health Agency of Canada (PHAC) increasing ventilation in indoor spaces like homes, schools and workplaces can help to decrease the spread of COVID-19. Plus, there are other changes that they have made to HVAC guidelines in light of COVID-19. In this guide, we will walk you through what you need to know about these changed guidelines for your workplace, home and school. 

COVID-19 Air Conditioner Guidelines 

The government of Canada has released some guidelines about how air conditioners should be used during the pandemic.  The government recommends that you use the highest MERV filter that the system can sustain. However, be careful, as each HVAC system will have a maximum MERV it can handle and higher MERV rated filters can put stress on the system, actually reducing its airflow, having a negative impact on your heating and cooling cycle. You should clean and change filters regularly. You should also run the system’s fan on a low level continuously in order to provide better ventilation throughout the space. 

Is an Air Conditioner Harmful in Regard to COVID-19? 

At the beginning of the pandemic in Ontario, there were concerns that the use of portable air conditioners and of portable fans contributed to the spread of COVID-19. Strictly speaking, they did. The use of portable air conditioners and fans propelled infectious droplets beyond their usual scope of two meters to other uninfected residents of some nursing and long-term care homes. Many of these facilities use portable air conditioners and fans in lieu of proper, building-wide ventilation and air conditioning. 

Now, long-term care homes and other healthcare settings need to use fans and portable air conditioners more wisely. They should only be used where a window can be opened to provide fresh air. They should not be directed at the door but aimed toward the resident, and to the ceiling. There are other regulations you may be interested in if you or a loved one are in a long-term care home. 

Air Quality and COVID-19 

COVID-19 has reinforced our understanding of how a quality ventilation system should work to protect us from stale air and the concentration of airborne debris, including viruses. The two essential principles are using good quality filters and using ventilation systems that draw air in from outside. Recirculated air from indoors is a poor choice as it can simply spread viruses around. High-quality filters are ideal to remove debris from the air when possible.     

Are There Air Ventilation Systems for COVID-19?  

No new ventilation system has been developed specifically for COVID-19. However, there are improvements that can be made to your HVAC system in order to support your health and the health of other occupants.  

Ideal Ventilation  

What is the ideal ventilation for your home or other space? In Ontario, the amount is calculated according to the ASHRAE Standard 62.2 Equation. A whole-building exhaust fan needs to provide a minimum ventilation as required by this calculation: 

Qfan = 0.01Afloor + 7.5(Nbr + 1)  

Qfan is the fan flow rate in cfm, which is what we are trying to solve for. Afloor is the floor area in square feet. Nbr is the number of bedrooms, and it should not be less than one even in an office building. The result of this equation gives you an amount in cfm. You can then simply purchase and install a whole house fan that meets this cfm.  

 Increased Ventilation  

What if you know that your current ventilation system does not meet your minimum? Or, what if you want to provide better ventilation than just the bare minimum? We have suggestions in each section below based on what kind of space it is, a workplace, home or school. 

Man putting up COVID instructions on shop door

Air Quality in the Workplace 

In the workplace, air quality is just as essential as elsewhere. People in office buildings, manufacturing plants and retail stores spend their time in close proximity with one another and can take home any illnesses that they catch. Air quality is important not just for the productivity and comfort of staff but also for their health and safety. How can you use your HVAC system to improve health and safety? 

Health Canada recommends that in nonresidential buildings, run the system for two hours after and before the building is occupied. Do so at maximum airflow. This helps remove all stale air and potentially airborne debris, starting each workday off with cleaner air. 

As in residential spaces, those in the workplace should clean and change filters regularly on all HVAC equipment. You should use the highest MERV filters that you can and that the system can sustain. However, be careful, as each HVAC system will have a maximum MERV it can handle, and better filters can put stress on the system, actually reducing its airflow, effectiveness and efficiency. Your HVAC technician can tell you what the maximum MERV your system can sustain is. 

HEPA Filters 

HEPA, or high-efficiency particulate air filters, are an excellent option to improve air quality in the workplace. Health Canada recommends using HEPA as a supplementary measure when proper ventilation cannot be achieved. Although you can also use it to improve air quality even when you have proper ventilation. 


According to Health Canada, a low humidity level could impact the duration that COVID-19 particles remain suspended in the air. Humidity should be between 30% and 50%. Lower humidity will keep droplets suspended longer than they should be. However, higher humidity can have a negative impact on your air quality and your home as well. It could encourage mold growth which then releases spores into the air. Not to mention that mold growth can damage your home’s surfaces and furniture. 

You may need a whole-home dehumidifier or a whole-home humidifier and may need to adjust the use of it based on the season. In Ontario, humidity drops in the winter and rises in the summer. 

Air Quality at Home 

HEPA filters can reduce the concentration of some viruses in the air. HEPA filters should be used as an additional protection where natural or mechanical ventilation cannot be achieved. Air delivery rate is critical as the filter needs to move a reasonable volume of air to actually make an impact. If it moves only a small amount of air, it essentially isn’t touching the bulk of the airborne debris in the air.   

Home Air Circulation 

When you’re improving your home’s air circulation, you have a choice of many different ventilation systems. While you can use local ventilation to improve conditions in select areas of the home, like the bathroom and the kitchen, you are typically better off improving the total ventilation in the home. You can use a balanced system without recovery, or one where an equal amount of air is ventilated as is drawn into the home. However, in our climate, heat recovery ventilators are superior in terms of energy efficiency, which still must be considered alongside air quality. 

Heat recovery ventilators (HRVs) allow you to achieve great ventilation with fresh air while also protecting the energy efficiency of your home. On the exhaust, they strip the heat out of the air before sending it outside. They then use that heat to treat the incoming air. Only a very small amount of heat is lost in this process. So, you get fresh air that is warm for winter. As winter is flu season, having this proper ventilation of air is critical. 

Are you looking for more information on indoor air quality? Let our team of professionals answer any and all of your questions. Give us a call today. 

Ventilation Guidance for Schools 

Schools in many areas across Ontario have improved their ventilation and HVAC systems in response to COVID-19. Schools have placed HEPA units into rooms, including those that are mechanically ventilated already. 

Ventilation guidance for schools requires that all rooms have ventilation and ideally full mechanical ventilation, which is driven by fans. School boards must use the highest grade MERV filters their system will support, which typically means MERV 13 filters. Those filters must be frequently changed throughout the year.  

In addition, schools need to operate their ventilation systems much like office buildings, where they open the system and run it at full blast for two hours before and after the students are on the premises. This cycles out stale air and creates a fresh slate for the next school day. 

Commercial HVAC Upgrade 

At Appleby Systems we can help any school upgrade their ventilation, air purification, and other elements of their HVAC system in order to comply with new Ontario-wide regulations about air quality. 

Need HVAC Support for COVID-19? 

There is, unfortunately, a lot of misinformation available about how your HVAC system, in a home, workplace or school, should operate and how it may affect the spread of COVID-19. 

To learn more about COVID-19 guidelines for HVAC Industry in Canada, contact the experts at Appleby Systems. 

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