Do I hire a construction litigation lawyer?

We hired a licensed HVAC contractor to install two HVAC systems in our recently purchased home. It was shared that we will have an insulation contractor spray foam our attic when we had the HVAC contractor quote the job. He quoted the job and installed two 80% gas furnaces. After reading the installation manuals and then hiring another company to validate my findings, our contractor that we hired installed 80% vented gas furnaces into a non-vented attic thus putting us into a dangerous situation. I confronted the HVAC contractor and offered him the opportunity to fix the situation. He installed 95% gas furnaces and didn’t pass building codes. We originally had a 3ton unit for downstairs and a 2ton unit for upstairs and our contractor installed two 3 ton units without changing the duct work or sizing the plenums to match the size of the coils for OEM recommended air flow. We know have water damage as the drains were not properly installed. Waiting for inspection report.