I own two single-family rental properties in FL, and I’m dealing with a similar issue in both: one or two bedrooms gets significantly hotter than the rest of the house.

In one property, the problem room is a garage that was converted into a bedroom. I’ve been told that inadequate insulation may be the issue, However, before spending money based on assumptions, I’d like to understand whether the real issue is insulation or something else.

At the second property, I’ve already dealt with HVAC/ductwork issues, including damaged/poorly insulated attic ducts, and the bedrooms has gotten hot compared with the rest of the house. Different HVAC contractors have suggested different solutions, including duct modifications and adding a dedicated return, which is exactly why I’m trying to avoid continuing to fix things by trial and error.

I'm assuming this is more of a seasonal problem during the summer, which is still a problem, considering it's south Florida.

For those of you who have dealt with hot rooms, what ended up actually solving the problem? Was it insulation, ductwork, adding a return or something else?

More importantly, what type of professional would you hire to diagnose this comprehensively rather than just recommend whatever service they happen to sell? I’m looking for someone who can evaluate the insulation/building envelope AND the HVAC/airflow situation and identify the root cause before I start spending more money.

If anyone can recommend a good GC, building-performance/energy-audit professional, HVAC specialist, or other expert in the Port St. Lucie/Treasure Coast area who is particularly good at diagnosing these types of problems, I’d really appreciate the referral.

And any good advice from someone who had similar cases will be much appreciated.