Our furnace gave up the ghost on December 17, 2019 and the DeMark name came up first when I google-searched and I am glad it did. You always wonder whether companies are Astroturfing their sites with positive reviews but I can assure you that I had no connection at all and in fact, had never even heard of DeMark before this week.
Mike (and Victoria, who I reached first) were great as were the guys who did the work. The price ($3,000+HST, so $3,390) was for a Goodman Model GMEC96, installed and with the old furnace removed. Not only did I find the price reasonable but there were NO add-ons, upsells or any other charges, plus it was arranged for the next morning after the evening on which our furnace died. Our house isn't big <1500 square feet, so you might need a bigger model if you have a significantly bigger house but it strikes me that this was a very reasonable overall cost and excellent service.