I got a 3 ton vertical loop system installed in September, so I'm new to geo. Not yet 100% sure what to expect, but when the system was sold to me, I was told the aux heat should almost never have to come on. Fast forward to December, and the heat pump can't keep up with even moderately cold outside temperatures, and I have to run aux heat if it's below about 20 degrees out. The EWT is 30 degrees, which I would think is cold for so early in the season? Installer insists this is all normal. Am I right to be concerned?