Upon arrival find sunroom door closed and a draft stopper at the bottom of the door. Customer stated the room does not warm up and no air flow noticed. There is a supply air to the room but no return air. Turned on furnace. Inspect filter and blower. There is a good volume of air coming out of the register. And more so if the door is open. The room does warm up. Just not like the rest of the house. Unfortunately it is what it is. Being that the room is all windows, no return air and thermostat location on opposite side of living space. The customer stated that with air conditioning the space cools better and they leave the door open. They closed it in the heating season because of the draft Under the door. Communicate with customer and hope they understand . Thanks Mark. Spoke with Ryan about this also. Office to invoice 3 Pillars.