The HVAC register was not blowing air. What's up?
Was the duct blocked?
If air was blowing, where was it going?
In this house this particular room was cold. Reaching up to the register I could not feel any moving air, but I could feel that the register was hot when I touched it.
So air was at least arriving to the spot.
But where was it going and how would I know?
I would break out Mighty Mo!
And I did! This is the perfect thing for a thermal camera to analyze.
Looking at the register this is what the thermal camera could see.
There was heat arriving to register and blowing into the cavity above the drywall! That heat was fanning out in all directions the air flow was allowed to go.
Why? There was a leak! An air leak. And likely because the duct had come loose from the register hood.
The image shows the joists above the register, which can be seen as blurry, blue lines. That round thing is a ceiling canister light fixture.
While the register is the warmest thing around it was not very hot by comparison to what it would be had the air been blowing right onto it. The house had a new heat pump, so the air would be in the 125F area. That the register was only 86F would indicate that more air was leaking than arriving to the register.
My recommendation: a thermal camera can analyze many things. Where HVAC air is going would obviously be one of them! My thermal camera is the sharpest arrow in my quiver. With it I can analyze many things, from plumbing to roof to electrical to mechanical to insulation. A thermal camera is not a point and shoot device! It requires real training and practice, practice, practice. The cameras and training are not cheap! And learning how to analyze the images is a little bit art and a little bit science. Seven years ago I wrote a post on that point which you can read here. Enjoy.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560