Please Tell Me Why My Room Is So Cold

I hear that all the time.  The flip side complaint is that the given room is too warm in the summer. 

This person said that the room feels fine when the heat runs, and then cools quickly.  Sounds difficult to diagnose?

It's not.  Remember, heat seeks cold.  It will move toward it.  People think that heat rises.  Well, it does, if it is seeking cold.  But heat can also go down to seek cold.

Also, interestingly, heat and cold don't mix.  I could demonstrate that with a thermal camera, but perhaps that is a post for another day.  Heat and cold separate until slowly, temperatures equalize to an ambient, common temperature.  Last year Jim Quarello posted a thermal image of a room showing the defined layers of temperatures as the heat was running and before the layers started to melt together to a common temp.  I called it layer cake!  Maybe he could post that again - it is extremely instructive.

But I digress!  Back to the bedroom in question.  It is the master bedroom, located in the front corner of the house, with two exterior walls and OVER the garage.  Rooms over garages are famously difficult to keep comfortable in extreme weather conditions. 

Investigating thermal image technology, this homeowner found me online.  A thermal image camera makes a quick, definitive, accurate diagnosis of where insulation is ineffective.  I suspected the windows were not great either - tract home, 15 years old, with big, two-panel, sliding windows.

This is a typical view of all the windows.  We waited for a nice cold morning, and outdoors it was about 20F when we began this inspection.

Notice that the panes are not bad, but not great.  The center of the pane is 58F.  But around the windows where the sliding sashes meet the frame the temps are around 41F.

And this is AFTER the client put extra weather seal in the tracks to help control air flow toward the indoors.  We could still feel air flow.

So we know the windows are a problem.

But what of the bedroom?

Since we have evidence that the windows are not sealing well, something else is going on.

First I went to the garage.  The images are taken from the garage door.  They look at the garage ceiling.

The left image is looking left and the right image is looking right. 

Those defined orange lines are heat escaping through the floor of the bedroom around joists.  "Oh, THAT'S WHY THE FLOOR IS SO COLD!" said the client.  You can see whole areas without insulation.

Why do I say without?  I think so because the coldest areas of the drywall are around 31F and those lines 62F.  They are not that much cooler than the ambient temperature of the bedroom!  The bedroom heat is seeking cold!

Next I went to the bedroom.

The left image is the left wall of the room, where the windows are.  The center image is the corner and the right image is the right wall of the room.

The coldest spot is the corner, around 30F!

And notice the walls, how the purple and lavender colors seem to be "dripping" upwards.  What's going on?  Heat is certainly exiting down.

I think the rim joist, which is a board or joist on the outside of the house nailed to the edges of the room's floor joists was never insulated.  There may be some insulation under the flooring, but it is either poorly placed or nonexistent on the outsides.

Insulation lesson:  TO BE EFFECTIVE, INSULATION NEEDS TO COMPLETELY SEAL A SPACE.  IT'S JOB IS TO TRAP AND HOLD AIR.  THAT TRAPPED AIR ACTS AS THE THERMAL BARRIER.  ALSO, IF IT IS UNDER A FLOOR, LIKE IN THIS BEDROOM, THE INSULATION MUST, ABSOLUTELY MUST, TOUCH THE UNDERSIDE OF THE FLOOR.  ANY GAP THERE WILL ACT AS IF THERE IS NO INSULATION AT ALL.  IDEALLY THERE IS A VAPOR RETARDER SOMEWHERE.  IF IT IS A PAPER-BACKED INSULATION, THAT PAPER VAPOR RETARDER SHOULD BE TOUCHING THE UNDERSIDE OF THE FLOOR.

At this point additional insulation is needed.  It might not be as hard as you think.  We had the same problem in the bedroom in our house over the garage.  To solve the problem my insulation company came and drilled holes between the joists at each edge of the garage ceiling and blew cellulose insulation into the space.  It completely fills any cavities, nooks and crannies and provides a great secondary seal.  It worked for us.  It would probably work for these folks.  The holes are then plugged with Styrofoam, which acts also as a fire seal.

My recommendation:  If you have cold, or hot, rooms, call an experienced thermographer to come have a look.  It is worth every penny to see what is going on.  And, if you recall, there aren't that many of us because one of the entrance requirements into the order is utter cuteness. 

Yes, we're all cute.