Upon arrival system was off. No power to the thermostat. Customer has a membership with Best Buy where he pays $300 a year to have free installation when he purchases items like thermostats. The gentleman came out and turned off the breaker for the AC at the main panel but not the breaker for the heat. When he tried to remove the thermostat and put the new thermostat on and touch the wires and caused the three amp fuse to fail in the air handler. There is a separate estimate that was X’d by the homeowner For the amount of money agreed to be paid upon by Best Buy. I also texted the same information to the gentleman at Best Buy and confirmed the email to send over the estimate to to be paid for. I suggest that the homeowner gets on a maintenance plan allows us to come in and test the equipment couple times a year, clean everything and take advantage of the benefits that come along with the maintenance plan and the customer agreed.. This estimate is to start the senior maintenance plan.