The longstanding world of HVAC is suddenly in the spotlight.

With research showing that the coronavirus can spread through shared air, property managers are rushing to modernize heating, ventilation and air conditioning systems before buildings reopen. This leads to costly upgrades to equipment that armies of professionals used to take for granted.

Construction professionals ponder how well high-performance filters block microbes and consider installing systems that use ultraviolet light or electrically charged particles in the pipes to kill the virus. Companies such as Honeywell International Inc., Carrier Global Corp. and Trane Technologies Plc, capitalizing on growing demand, offer everything from air monitoring sensors to portable filtering machines to compensate for deficiencies in ventilation.

“Every building will have a solution. Will it be 100%? No, ”said Hani Salama, head of the New York Chapter of the Building Owners and Managers Association. “But it will be better than what they have now and will help alleviate some of those airborne transmission problems that everyone is afraid of.”

Much of the concern for buildings has centered on whether the virus can spread through surfaces, which has led to remedial measures like new cleaning practices, gallons of hand sanitizer, and touchless doors and bathroom fixtures. However, more than 200 researchers have asked the World Health Organization to recognize that air currents can spread the disease.

A study led by researchers from the University of Oregon earlier this spring found the presence of the virus in a quarter of HVAC systems in hospitals treating Covid-19 patients. The results suggest the potential for common air transmission from locations separate from the infected person, the authors said.

Not all experts agree. The virus would dilute and break down even if it got into the air ducts, making them ineffective conduits, said Edward Nardell, a Harvard University professor who studies airborne transmission. He is more concerned about people returning to buildings with inadequate air circulation, which allows the virus to linger in a room.

There are many compromises for builders. It is best to let in more fresh air, but that puts a strain on cooling or heating. Dense filters that trap more microbes are in great demand, but can restrict airflow and degrade ventilation if a building’s fans are not powerful enough. And most of the solutions require higher energy consumption.

Building security products are proving to be a bright spot in sales for companies like Honeywell, which has “smooth entry” technology, automatic temperature measurement and sensors to monitor air quality. Carrier, which specializes in HVAC and is reporting earnings this week, has been stocking up since it split from former United Technologies Corp. in March.

“We’re seeing a lot of demand,” said Manish Sharma, chief technology officer for Honeywell’s building technology division. “Everyone wants to see how to get back into business.”

Air conditioning upgrades are a top priority for landlords, said Salama of the New York Association, although it is unclear when office workers will return. His company, Capital Properties, is replacing 900 air conditioning filters in its two Manhattan office buildings for twice the price it would normally pay.

Many of the methods of reducing pathogens have been around for years, such as UV light and bipolar ionization, which release electrically charged atoms that attach to viruses and bacteria and neutralize them. These technologies were geared towards hospitals rather than commercial buildings, which placed more emphasis on saving energy than killing germs. That is changing now.

Allan Reagan, Chief Executive Officer of Flix Brewhouse, adopted sophisticated sanitizing and social distancing protocols in its 10 dine-in theaters. When the risk of airborne spread attracted more attention, he contracted Trane Technologies to install bipolar ionization for all of the company’s 87 screening auditoriums for $ 1,500 each.

A study showing the system kills up to 99% of pathogens convinced Reagan, and the Flix Brewhouse in San Antonio was opened to the public for two weeks to try the system. He said the venue had around 700 visitors, including 50 employees, and he hadn’t heard of any Covid cases that had occurred. All Flix cinemas are closed for the time being, mainly due to the lack of new films from Hollywood, he said.

“We tried it, declared victory and will come back when we have good content,” said Reagan. “In the meantime, we’re retrofitting our other theaters. When they reopen we will have this technology all along the way. “

Fredric Lubit, a dentist with two offices in New Jersey, bought four Carrier OptiClean air washers for $ 4,500 each. The machine, which resembles a tall filing cabinet, sucks air through a highly efficient particulate air filter or HEPA filter. He also bought a $ 10,000 machine for each office that saturates a room with UV light for two minutes to destroy microbes.

Carrier began developing the OptiClean in March by adding a larger fan and motor to the interior of a residential HVAC system along with other parts. The product was originally intended for hospitals, but now demand is coming from schools and small offices, said Chris Nelson, president of Carrier’s HVAC unit, who declined to report sales.

It’s unclear whether the virus could catch on. While studies have shown that HEPA filters can block particles as small as 0.1 microns, which are tiny enough for the coronavirus particles that can float in the air, the rating of high-performance filters is according to a July 9th only for particles with a size of 0.3 micron paper from the consulting firm McKinsey & Co.

For Lubit, the effort is still worth it.

“You cannot quantify your health, the health of your employees, and in my case the health of your patients,” he said.