As you know, your geothermal heating system is extracting heat out of the ground to heat your home. During very cold temperatures, the heat pump runs 100% of the time, just as it is expected to do. During the cold days, the geothermal heat pump runs constantly and the supplemental heat assists as needed. But do not let this alarm you. Considering the entire winter heating, the geothermal heat pump will supply most of the heat needed and a much smaller percentage is created from the backup or supplemental heat.
As we absorb heat out of the ground, the ground temperature in your loop field will decrease. This is normal. The loop is not expected to stay at 50 degrees. During very cold periods the loop will reach 30 degrees and lower. This is still OK. Geothermal technology is very capable of extracting heat from a cooler liquid, even if it is in the 20s. If you are familiar with a conventional, non-geothermal heat pump, these systems are actually absorbing heat from -10 degree air, so the geothermal system is still doing much better with ground temperatures than the conventional air to air heat pump.
We anticipate the loop will get cold when the weather gets cold. This is why we use an antifreeze solution in our geothermal loops. We know they will get below 32 degrees. This is why we insulate your loop pipes when they enter the home. If a loop pipe, a loop fitting, the loop pump assembly or any other 30 degree cold surface in the home is left exposed, it will first condense moisture and then the moisture will freeze or at least frost over. This is normal and should not cause any problems with the operation of the geothermal heating. Ideally, all cold surfaces would be insulated, but some parts, such as the loop pump assembly is not insulated.
These are great questions. We appreciate our Precision Comfort Systems customers and their interest in all things geothermal. Here is some additional valuable information about your heat pumps during very cold weather.