Other heating options vs stock setup using exhaust?

I have a "Florida Car" a converted 77 targa that now looks like a 93 sc convertible. I am now living up north and the hoses, fans etc for the heating system are all disconnected and would take some work to put back together. Is there an aftermarket heater used on the 911 or Bug that can be used instead of the somewhat risky (Co2 fumes) exhaust on a regular 911. Info would be appreciated. thank you.