FLIR thermal camera observations
Posted: Sun Jun 07, 2020 12:20 pm
This thing is fun! I made my first surprising discovery. I had put some supposed heat blocking film on one door of my office patio doors (intended to finish the other door later) because the office became quite hot even with blackout curtains in the summer. I wondered what the heat reduction by the film is. So I spot checked each door and the door with the film was 4 degrees F hotter. So I did some reasearch and found that things are not simple. The film is absorbing the IR and heating up. Now the question is how much of that heat is simply re-radiated into the room and how much is radiated back outside. We can't tell but assuming that at least some is going back outside, then the film would be helpful even if the spot thermometry shows it hotter.
So now I am thinking to use reflective film which will not heat up the glass. But then how to tell how much interior heat reduction we are getting? Spot thermometry will simply show the ambient exterior temperature. So here's my plan. Put a conventional thermometer in the space between the blackout blind and the pane. Check the temperature with and without the film. That space is like a little greenhouse, so we expect it to be cooler with the film. I will report my finding after getting full direct sunlight later today. That will be with the absorptive film. I'll also get some reflective film and see how that works.
So now I am thinking to use reflective film which will not heat up the glass. But then how to tell how much interior heat reduction we are getting? Spot thermometry will simply show the ambient exterior temperature. So here's my plan. Put a conventional thermometer in the space between the blackout blind and the pane. Check the temperature with and without the film. That space is like a little greenhouse, so we expect it to be cooler with the film. I will report my finding after getting full direct sunlight later today. That will be with the absorptive film. I'll also get some reflective film and see how that works.