I purchased my Xtreme Heater in August and used it successfully throughout the winter. As a new boat owner, I was very apprehensive about relying on a small plug in heater to protect my engine block from cracking. All of my boating friends advised me to winterize my boat and forget about it for 3 months. I didn’t, and got to use my boat when other’s couldn’t. Score! Saved me Large Winterization Bills! You can bet I’ll be recommending Xtreme Heaters to my friends!