I have what is called a "Hip" type roof. I have ample soffit vents but very little ridge venting due to the design. To combat this the builders installed a exhaust fan that posseses a thermostat. Recently we were informed that we had frost on the underside of our roof sheeting. To combat this the builder installed a timer on the exhaust fan in order for it to come on at periodic intervals throughout the day, once in the early morning and once in the early evening. My concern is that in doing this "fix" I am afraid that with only a periodic function of the exhaust fan have they not sacrificed the benefits of the exhaust fan in the summer when the thermostat would have been more beneficial.