Its 6 degrees outside right now, Monday has a high of 9-12 degrees. At keast its not windy. My Reznor has no problem keeping my garage at 60 degrees or warmer, per the heat loss calc i didnt need anything over 60k btus due to descent isulation and a finished, heated mother in law suite over the garage. Reznor is a great brand and they re worth the extra money imo.