We bought a hot water tank at Home Depot, and Friesen was the contractor to install it. We upgraded from 40 to 50 gallons. When the installer arrived, he took a look at the tank site and stated that only a same sized 40 gallon tank would fit. He also stated that the venting had to be upgraded from 3" to 4", requiring a permit, for an additional cost of $250. And he charged us $70 for a "wasted trip" that took him less than 10 minutes.
We decided to go with another company, and they had no problems installing a 50 gallon tank in the same location as the old 40. The vent upgrade also did not require a permit, and the labour was $150. Altogether the job was $150 less than with Friesen/HD.
I suspect that the HD contractors will only do the simplest jobs because that way they can do several jobs in a day. HD said that it would take them an hour to do the job. The company we went with took three hours without any problem or complaint. So, much better value and service from the competition!