We've been having a decent cold stretch in upstate NY with several nights between 0 and -10 F over the past few weeks, and days that are only 10 to 20 F. I had been concerned seeing my EWT dropping from around 37 in the beginning of the month to 33 F now. Having read some on this forum, it sounds like anything over 30 F is nothing to sweat about, so I do feel somewhat reassured about that. Still, my system has been struggling to keep the house warm. We have it set to 67 overnight and 69 in the day, and I've been finding myself turning on the fireplace to help get the temp back up. My system has been running in stage 2 for the past few hrs, and the air leaving is at 89 F. Should it be any warmer than that? If not, then maybe it's just a matter of my house not being as well insulated as I'd like. FYI there is an electric backup, but I keep it disabled just because it uses so much electricity.