AHA! I think.

One of the first things I did when my husband moved out in 1994 was to hire a heating and cooling company to figure out why my furnace shut off before the house got warm.  We moved in here in 1972 and my husband insisted that there was no problem with the furnace.  Never argue with an engineer.

So, the guy comes and I explain the problem as I see it.  He goes up and down the stairs several times, turns the furnace off and on again, walks around the house and then asks me to join him in the living room, next to the thermostat.  He has me place my hand next to the thermostat on the wall and the wall is roasty, toasty.  He then tells me to move my hand out to the side, in either direction.  The wall is cold.

So, here is what the idiot builder did when he built the house.  He placed the thermostat in front of the vent pipe for the furnace.  The furnace comes on, the vent pipe gets warm, the furnace shuts off, the house stays cold.  Solution, move the thermostat to a new location, in this case, the dining room.

While that solved most of the problems, I still had a front corner bedroom at the farthest run from the furnace that was always colder than the other rooms, sometimes by as much as five degrees.  I had it looked at but every solution offered was to just use a small space heater.  Since the bedroom was on a slab foundation, they said there was not much they could do and they did not think an air-flow booster in the duct would help.

Still, I was always sure that something was blocking air flow across the front of my house.  And I wasn't the only one with problems.  A neighbor in a tri-level house had cold upstairs bedrooms.  In taking apart the stairwell where the ducts travelled, they discovered that the duct work had not been installed completely.  There was a three foot gap!

Last week I had all the duct work thoroughly cleaned with one of those truck mounted sytems.  Whatever they did, they must have dislodged the blockage.  Now when I walk into this bedroom where my computer is, I am hit with a blast of warm air.  THAT has never, ever happened before.  The outside wall shows 66 degrees instead of the 59 that it read before.  (Ya gotta love laser temperature readers.  And yes, my thermostat is set at 66 degrees with 50% humidity.)

I'd been looking at insulated siding for this south wall of the house.  Now, maybe, I'll use the money on something else and just repaint the wood.  I hate to say I was always right, but in this case, AHA, I think I was.