My garage is very cold. Who do I call?
Usually, start with
Home-performance / insulation professional
If the garage is consistently much colder than expected, a home-performance or insulation professional commonly evaluates insulation coverage, air leakage, the garage door and other parts of the thermal boundary, and the separation between the garage and adjoining conditioned space.
Change course if
The garage has a heating system that is not keeping up
An HVAC professional may be relevant when installed heating equipment is part of the complaint.
Most of the cold air seems to come through the garage door
A garage-door professional may be relevant to evaluate the door, perimeter seals, and weather stripping.
A room above or beside the garage is the main comfort problem
A building-performance or insulation professional can evaluate the assembly separating that living space from the garage.
Who handles what
Insulation / building performance
Evaluates insulation, air leakage, and thermal boundaries around the garage and adjacent living space.
HVAC
Evaluates installed heating equipment and conditioned-garage systems.
Garage door
Evaluates door construction and perimeter sealing where the opening appears to be a major source of air leakage.
What might be happening
Many garages are intentionally less conditioned than living spaces, so some temperature difference is normal. Larger-than-expected differences can reflect insulation levels, air leakage, door construction, heating equipment, or the way the garage connects to the rest of the house.
Useful things to notice
Where the cold is most noticeable
The garage door, exterior walls, ceiling, or a particular corner can help focus an evaluation.
Whether there is living space above or beside the garage
Adjacent conditioned rooms change which assemblies matter most.
Whether you can feel obvious drafts
Air movement around doors, penetrations, and wall or ceiling joints is useful to document.
Before you call
Note whether the garage is heated, whether living space is adjacent, and where drafts or especially cold surfaces are noticeable. Photos of exposed walls, ceilings, door seals, and existing insulation can be useful.
Before you fix the visible symptom
Adding insulation in one visible area may not address air leakage or the actual thermal boundary. An evaluation can help identify which parts of the garage assembly are relevant before materials are added.
References
U.S. Department of Energy. Insulation and Air-Sealing Essentials.
ENERGY STAR. Seal and Insulate with ENERGY STAR.
U.S. Department of Energy. Insulate Your Home—and Your Bank Account.