Excess humidity with heat pump - vapor barrier?

Hi! We've noticed an increase in moisture in our house since installing a heat pump (+ humidity outside has been higher lately) and have been advised to install a vapor barrier, which we know nothing about. Anyone have one recently installed? Any recommendations on who to reach out to whether this is the kind of project that warrants multiple estimates or can offer any other advice on how to proceed? Thanks!

Parent Replies

New responses are no longer being accepted.

As a retired architect who has projects in many different climates, I can tell you this is a tricky question. 

First, know that to install a stand alone vapor barrier means removing wall finishes—either exterior or interior depending on the climate. The vapor barrier should be installed on the warm side of the wall. In a climate such as ours, now that the climate is changing, there is no longer a typical warm side. If the vapor barrier is not correctly placed, moisture can be trapped in the wall cavity. Newer technologies such as blown-in solid foam insulation that provides both an air and vapor barrier address these problems.

Best bet: contact three (or more) general or insulation contractors, ask what they recommend, and get an estimate for each. This will not be an easy or inexpensive project.

Do you have mini splits or a ducted system? Our mini splits have a "dry" setting that takes moisture out of the air, which also cools it slightly. Wondering if this might help your issue?