Sealing homes' leaky HVAC systems is a sneaky good climate solution

Behind the walls

But it is not just new homes that Aeroseal tackles. Ductwork in older homes is a major energy efficiency issue. A typical American house loses 20% to 30% of hot and cold air through leaky ducts, according to the Department of Energy, creating an incredible opportunity for savings.

If you have high energy bills or big temperature differentials from room to room, you likely have leaking ducts. But HVAC contractors rarely make this connection for homeowners and renter, says Amann. It’s also hard for individuals to understand, let alone, prioritize behind-the-scenes repairs.

Sealing ducts is also an arduous process: Accessing them can be difficult because most are behind walls once a building is completed.

For existing buildings, including single-family homes and commercial buildings, Aeroseal can narrow the process so that technicians focus on ducts alone instead of sealing the whole building. The first step is to block all the known vents in the system and detach the boiler. Technicians then attach a tube to the vent system and hook up the computerized measurement machine, allowing them to do the pressurization. This process can reduce leakage by 95%, the company says.

Going forward

Amit Gupta, the company’s president, previously worked in energy efficiency at Carrier Global, the Florida-based HVAC systems giant. He recalled being wowed by the possibilities of Aeroseal’s technology.

“Here we were spending millions to improve the efficiency of a new boiler by just 2% and this is a way to address something that is there and a problem in every building,” he said.

So far, Aeroseal has been doing about 56,000 seals (sometimes there are multiple seals in a big building) a year. Last year, the company had revenue of just under $40 million. Part of the challenge to growing the company further, said Gupta, is getting contractors to pay upfront for the energy savings that will accrue over time. The average national cost for an Aeroseal treatment is $2,500, the company says. If no one is measuring the emissions of a building, an owner might opt for a cheaper option with a far less thorough seal.

But new laws, like New York City’s Local Law 97, which goes into effect this year and aims to reduce emissions of buildings over 25,000 square feet by 40% by 2030, are creating standards that strengthen Aeroseal’s position, Gupta says.

This law “creates the driver for building owners to reduce their greenhouse gas emissions,” said Gupta, and it is already fueling growth in the business.