I bought a duplex that was built in 1978 in Indiana. It gets moisture on ceiling so bad during winter when temps drop below 20 degrees that it will run down the walls & look like its raining. Contractor says there’s enough insulation in the attic. There’s wood siding on 3 sides & brick on the front of the house. I want to put metal siding over the wood & add insulation in between. Will this solve my moisture problem on ceiling or do you think the units need new heat pumps which are at least 15 or more years old?