Can this be switched to propane?

Yes, we do offer this Modine Hot Dawg HD 100,000 BTU unit with a liquid propane fuel type. The SKU is HD100SS0111 / HD/HDS 100. Provided is also the link to the unit - Modine Hot Dawg HD 100,000 BTU Liquid Propane Garage Heater If you have any further questions please feel free to give us a call! Thanks.