Heat pumps are very common in the US. That part isn’t really a challenge.
I don't get what this startup is offering. Heat pumps are common and readily accessible, I can walk into lowes and buy one today and they can arrange a contractor to do the install. It'll be a lot less expensive this this setup.
If your business plan starts with "X is rare and hard to find" and X is actually extremely common, you're not going to be successful.