In October 2017, Anil Arora sat helplessly in San Francisco as the Tubbs Fire approached his home in Calistoga, California.

Arora watched through a Ring camera as the fire worked its way through his yard before consuming the rest of his property. That night, Arora and his family could smell the smoke from the fire that had burned down their home, more than 70 miles away.

“It was just a shocking scene,” Arora said. “The day after, we just sat down and discussed it and said, ‘You know what? We’re going to rebuild.'”

As the family planned their rebuild, Arora knew he wanted roof sprinklers for the home so it would never burn down again. After scouring Google for options, Arora came across Frontline Wildfire Defense, a start-up that had just created a sprinkler system that was exactly what he was looking for. Two years later, he had a new home with a dozen sprinklers on the roof, each capable of shooting water and foam up to 30 feet in every direction.

Arora is among a growing number of homeowners turning to climate tech start-ups to harden their properties against natural disasters that are increasing in frequency and potency as a result of global warming. 

California wildfires are “something that we would see anyway, regardless of climate change and regardless of population, but when you add climate change into the equation it increases the opportunity for fire,” said Harry Statter, CEO of Frontline, which has raised $3 million in funding. 

In August, the United Nations’ climate panel delivered a dire report calling for immediate action. The agency warned that limiting global warming to close to 1.5 degrees Celsius or even 2 degrees Celsius above pre-industrial levels “will be beyond reach” in the next two decades without rapid and large-scale reductions in greenhouse gas emissions. The report said that at 2 degrees Celsius, heat extremes would often reach critical tolerance thresholds for agriculture and health.

“We had a house burned down, so it’s very real for us. It’s not a conceptual thing,” Arora said.

As homeowners think about how they can defend their homes, entrepreneurs and investors are starting to pour their time and money into this largely untapped market. 

“What we have right now is an opportunity to get those best and brightest minds to go and work on something that is actually worthwhile,” said Greg Smithies, partner and head of climate tech at Fifth Wall, a venture capital firm. To date, Fifth Wall has raised more than $300 million for its climate tech fund. 

Through November, more venture capital money has been invested in climate technology in 2021 than any year prior, according to data provided by PitchBook. Nearly $26.7 billion has been invested in climate tech in 2021, up from $15.3 billion in 2020 and $11.8 billion in 2019, according to PitchBook.

With homes and buildings specifically, climate change poses a risk to as much as $35 trillion of real estate assets by 2070, Smithies noted, citing a 2016 report by the United Nations Framework Convention on Climate Change. 

“The opportunity here to have a start-up to make a whole whack of cash just given the size of the market is very easily much larger than any of the opportunities we saw instead,” Smithies said. 

The point of Frontline’s system is to wet down a property, hydrating the combustible vegetation surrounding a home and the building material, making it less likely to light up if a fire approaches, Statter told CNBC. The system can be activated by flipping a switch within the home, or through a Frontline mobile app. If a fire has caused Wifi or cell connection to go down, the system can also connect to Frontline via satellite, ensuring that a customer can activate the sprinklers no matter what, Statter said.

The company is also planning to release a new version of its app in December that will provide comprehensive wildfire safety information in near-real time for anybody. That includes a map that shows wildfires, evacuation warnings, orders and safe to repopulate statuses, the company said. 

“You don’t have to be a system owner to use the new app,” Statter said. “This is for reducing risk to really anybody who lives in wildfire areas.”

The defense system cost Arora approximately $10,000, although Frontline’s systems typically average between $15,000 and $25,000, according to Statter. Arora said he decided to rebuild the home due to his family’s emotional attachment to the place where his kids grew up. Paying $10,000 for the fire defense sprinklers was well worth the money, he said. 

“It is an emotional investment and a financial investment. Our kids grew up there attached to it,” Arora said. “You want to make sure that you’re doing everything you can.”

Arora turned on the system to wet down his property a few months ago when there was a fire nearby, but he has yet to rely on the system to fend off a fire. But perhaps most important, the system is something tangible Arora can do, rather than watching passively.

“What it does for me most of all is peace of mind,” Arora said. 

Tech worker Sylvia Wu and her husband were on a road trip in September 2020 when they grew anxious. Wildfires had started spreading in Santa Cruz County, California, and they were getting uncomfortably close to their home in Corralitos.

Fortunately, nothing happened, but in June 2021, the couple decided to take steps to protect their home. Wu got in contact with her former colleague at Uber, Jahan Khanna, a serial entrepreneur whose latest start-up, Firemaps, helps homeowners harden their homes against wildfires.

Firemaps uses technology such as drones, computer vision, satellite imagery and artificial intelligence to analyze a home and determine what parts are most at risk to wildfires and what steps can be taken to improve their resilience. 

Firemaps creates a 3D model of the home and presents the homeowner with a list of recommendations. After the homeowner decides which ones to accept, Firemaps puts the jobs up for bid to its network of contractors, all of whom it has previously vetted. Firemaps doesn’t charge homeowners for the service, but instead takes referral fees from the contractors.

Khanna said he and his co-founders felt like not enough was being done to protect homes from the rising risks of climate change. 

“The founding team all lives in California. We’ve been dealing with wildfires ourselves,” Khanna said. “It didn’t seem like there were that many people working on the practical impact of climate change in the here and now. That seemed like an opening and a need we could fill.”

Firemaps determined a number of steps Wu and her husband could take to protect their home.

This included raising the canopy of trees surrounding the structure, cutting down a bamboo grove, removing a big tree that was right next to the house, reducing the size of ornamental bushes and grass around the house and putting down decomposed granite, which is not flammable.

“I have always meant to just like go out there with a tape measure and measure things, but, you know, you get busy, you get lazy and I never did it,” Wu said. 

Wu and her husband decided to go through with the recommendations, and after two full days of work, the contractors were able to complete the job. With her friend discount, Wu said she paid $4,000 for the job. 

“Nothing is going to prevent your home from burning down if the fires get really bad,” Wu said. “There’s always a chance of that, but I wanted to just make sure I took all the precautions I could. Anything beyond that is not really within my control.”

Once a job is complete, Firemaps makes another 3D rendering of the home. The company verifies that the work was done properly and communicates that to the homeowner’s insurance as well as the local fire department and any other entities that need to know, Khanna said. 

Because climate change is an intractable global problem, Khanna said, people are going to have to take steps to protect themselves.

“People’s first tendency is to move away. But people need to get their heads around the fact that this is a large scale crisis, and it’s not going to go away,” Khanna said. “Absent us doing that hard work, it’s going to continue to get worse. We have to deal with this problem or it’s going to get worse.”