A few weeks ago I smelled gas outside of our home. By sheer coincidence I had seen a Hydro truck down the street earlier in the day so I called the emergency line just to be safe. They sent someone out within an hour and tested our meter and the neighbours as well and to our surprise it was OUR furnace leaking Carbon Monoxide. It was shut off IMMEDIATELY and within 24-48 hours Fred from Markham Heating & Air Conditioning came to our rescue and replaced the defective part. It took longer then we or he (I think) thought it would but he finished everything and was really professional and friendly. It was just in time too as the temperature dropped but we were warm and felt safe. We had no idea that it was leaking and none of our detectors had gone off. We actually feel a lot better now and will be having our air conditioner serviced shortly as it is now super HOT. I can see why this company has been in business for sooo long and was surprised that I am the first to write a review on Homestars but I am happy to share my positive experience and I am sure there will be many more excellent reviews very soon.