Our shop has a furnace that uses propane that we set to 40 degrees just to keep things from freezing. However, it's rarely 40 degrees in our shop. To supplement the heat source a wood burning stove was installed a few years ago. During the week days the furnace rarely runs and we are able to maintain mid to upper 60's during our work day. In my opinion every maintenance department should have an alternate heat source. Another club I worked at burned used oil from the equipment and carts to help heat the building. Here is a picture of our wood stove.