I have a 100 years old building with a store on the main floor. Since the building was built over 100 years old there is no ducting whatsoever. There is also no furnace. In the summer we just hook up an air conditioner through one of the windows. In the winter we have a heater blowing the air.
Is an HVAC needed to get ventilation? Or can I just purchase an Air Exchanger? I assume I now need to install ducting in the store? What is the best solution? Of course the HVAC companies are going to sell me their latest and greatest products out there.