There were optional gas-fired heaters for both that worked, too well. Fire hazard, didn’t last long. The lack of decent heat wasn’t as big of a problem as the associated lack of an effective defroster in very cold weather. You can dress for cold and wear gloves to drive, but constantly having to scrape your frozen breath off of the inside of the windshield while driving is just not very workable.
Great cars, the both of them, though. I’d dearly love to have a nice second generation Corvair, just about all the challenges of a rear mounted air cooled engine were solved by that car, truly a poor man’s Porsche and more advanced in some ways than the Porsche of the same era. Beautiful example of Bill Mitchell era GM styling, too. Very influential.
Re the frost - I kept an ice scraper in the front seat - didn’t need it WHEN the heater and defrost worked, but every now and then it came in handy.
From what I’ve heard and read, the issues with the Corvair were very much hyped. I think it was a car way ahead of it’s time. Perhaps the Edsel was, too, but I don’t know much about that, so not going there.