20 year old Lennox heat pump - outside temps been 30's at night, 40's daytime
UPDATE: I went outside and the unit is covered in frost on 3 sides! I've been reading on Google about frosted heat pump units and can't determine how to manually defrost it. Apparently, the auto defrost is not working. Can I turn it on A/C to defrost quickly? How about turning it off via inside thermostat?
Thanks for your time.