My hubby believes that any time you have that much power pulling where it keeps lights in house dim--it isn't good. (He says that isn't good on motors and things). We really believe it happens because of the heat strips or maybe it's because the geo runs harder in the winter to keep up vs summer. I just thought that it runs all the time and there would be no difference. I'm hoping someone has noticed same with their geo.
When the heat pump starts there could be noticeable voltage drop for few seconds. If the lights remain dim during the HP operation you should investigate why. It might be bad connection between the breaker panel and the transformer or the cable isn't sized properly. Either case is potentially dangerous in the sense that the bad connection or the undersized cable can overheat and start fire. The heat pump shouldn't take more power than a stove. Heat strips, on the other hand, can take significantly more.
We have geothermal unit that draws about 5 kW when running. We don't have heat strips. Our lights dim for a fraction of a second when the unit starts only. Our transformer is about 35 ft from the breaker box.
