Thanks to everyone for providing so much information in this forum. With the rising fuel cost more and more people will be looking for alternatives and this site is a great place to start. Well this is my first post, but I have been reading posts for about a year now. I just ordered a Tarm Solo 40. My boiler won't be available for pickup or delivery until Aug/Sep due to the overwhelming interest. Tarm can't keep up with the demand. So my plan is to install the boiler in our barn which is approximately 100' from our house and tie it in to the existing oil boiler we presently use. I was told by the dealer that I purchased the boiler from that I needed to use glycol to prevent the possibility of freezing. Can't I send heated water back to the Tarm from my oil burner to keep it from freezing? The Tarm will be running all the time during the heating season, but if for some reason I was out of town or otherwise unable to fire the boiler I need a way to keep it from freezing. Thanks again.