As hotels consider reopening amid the COVID-19 pandemic, many are experiencing pressure to completely change the way they operate their HVAC systems. However, according to Matt Ganser, EVP of Engineering and Technology, Carbon Lighthouse, the data available on COVID-19, other viruses, and on HVAC systems does not indicate a need for extreme measures. Instead, more reasonable changes to HVAC operations will be just as effective and less money upfront as well as less money to operate in the long-term.
1. What kind of extreme HVAC updates are some hotels being asked to implement in the name of safety during the COVID-19 pandemic?
I have heard recommendations along the lines of 100 percent outdoor air or 24/7 operations. Some have even suggested using HEPA or MERV 16 filters. However, these extreme changes may not be necessary and often require hefty increases in operational costs.
For example, while there’s no COVID-19 specific study for ventilation rates yet, there are useful analogs that have studied other viruses like influenza that do warrant a sensible cautionary change to business as usual. While 24/7 circulating air might sound good in theory, there’s actually a large kink in the relative benefit in the order of two to four air changes per hour in space, above which additional ventilation has strongly diminishing returns both in a financial and safety sense.
And even if the virus particles survive the journey through the HVAC ductwork, the current emphasis on HEPA or MERV 16 filters seems misplaced. Although the virus particles themselves are very tiny (0.1-0.3 micron), the particles they ride on are generally larger, making a MERV 13 as effective as a MERV 16 or HEPA filter without the unnecessary upfront expense or, more acutely, the increase in utility bills due to the extra fan power needed to overcome the finer filtration.
Just, how much more money are we talking about? Using our patented AI platform CLUES, we found that a typical building (115,000 square feet) has a baseline utility spend per year of roughly $230,000, with $100,000 of that spent on HVAC. Buildings implementing extreme COVID-19 HVAC measures, without energy-saving technology already in place, could experience a significant increase in utility spend to $370,000.
2. What are some more reasonable actions hoteliers can take with their HVAC systems to ensure health and safety?
Hoteliers face hard choices in the months ahead as they determine the necessary course of action for their employees and guests. Numerous voices are providing guidance for safe re-openings, including industry leaders like ASHRAE which takes a highly conservative approach with a focus on occupant safety. Hoteliers should follow CDC guidelines and focus on mitigation strategies first and foremost, including maintaining low occupancy densities and cleaning thoroughly. Consider incorporating Ultraviolet Germicidal Irradiation (UVGI) in hotel public restrooms and highly trafficked locations like the elevator or hotel gyms, as an additional layer of safety for occupants.
HVAC strategies are a secondary defense and can be addressed effectively without doubling utility spend. Appropriate strategies include setting HVAC systems to circulate two to four air changes per hour in space and increasing the filter rating from the standard 8 MERV to 13-16 MERV.
Hotels can also consider mixed-use opportunities for the least energy-efficient spaces, like large conference halls. They should explore how these areas can be used differently to reduce operational costs and make them more attractive to guests or corporate RFPs, as well as understanding how to optimize HVAC systems and lighting to be adaptive to the current usage.
3. What should hoteliers be focusing on instead of these extreme HVAC measures?
The current conversation on immediate safety concerns is missing the larger and synonymous opportunity to make properties’ back of the house systems more adaptable and resilient to the certainty of shifting occupancy and variable load demands caused by the pandemic and resulting recession. Investing in data-gathering to modernize operations is an opportunity to control costs while future-proofing. This can all be done by simply focusing on optimizations, without purchasing new equipment. Resetting static setpoints, identifying optimal start/stop algorithms, enhanced zone level controls, temperature and flow point optimization, and making central operational changes enabled by advanced data collection and analytics, can help not only balance any near-term operating costs associated with COVID-19 HVAC mitigation but drive them down. The COVID-19 crisis does provide a silver lining as it relates to modernization. A resilient building today is an efficient building tomorrow.