Don't let these people into your home. They are very dishonest and will overcharge by a lot and not do a proper job. They quoted us $1100 to replace the heat exchanger in our furnace and adviced us to buy a new furnace instead since ours is 14 years old. We had another company come in who did the job for $300! Unfortunately too many companies such as Don's don't want to fix furnaces so they over quote on jobs to try to get people to just buy new instead.
Don's was originally out to do a service on our furnace. This was not done properly either. We had them out again to redo it and they still failed at doing a proper job.
I also left a review on their Facebook page only to find that they have now removed the section where people can leave reviews. This says a lot about their dishonesty!