Drafty house thermostat installations

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9,373
Location
Canuck living in California
Thread starter
I just replaced the thermostats in my house and noticed the downstairs one had a cold draft coming through the hole in the drywall where the wires were run. My previous house had the exact same problem and that cold draft will cause the thermostat to cycle the furnace more often. I sealed it up with some expanding foam and it does seem like my furnace is cycling less often now. These thermostats were all installed on internal walls, so Iin theory there should be no drafts, but we all know the quality of "pro" work these days. Something to keep an eye on.
 
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437
Location
Canada
Usually on the exterior walls, there is a vapor barrier box that goes behind the electrical receptacle and needs to be taped to the vapor barrier to form one continuous barrier that would block the drafts. See below [Linked Image from house-improvements.com] The thing is, I've never seen a thermostat on an exterior wall and it's intriguing that you have a draft in an interior wall...
 
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544
Location
SE Alabama
Your drafts could be coming from a hole in either the top or sole plate where wiring or plumbing is being run. I'd check both of those and get things sealed up. Not only does it cause efficiency issues, but it's a great way for vermin to get inside the walls. If you have a slab house then it's most likely the top plate. A can of Great Stuff and a couple hours of time would be a very good investment. While you may have sealed around the thermostat, you'll still have a cold spot on the wall.
 
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4,107
Location
SW Ohio
Originally Posted by KrisZ
....so Iin theory there should be no drafts, but we all know the quality of "pro" work these days.
As fawteen mentioned, there may be "holes" in there intentionally for different bits of infrastructure. I doubt there's anything like a giant, gaping hole from poor quality construction like you're thinking.
 
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12,022
Location
OH
Originally Posted by KrisZ
These thermostats were all installed on internal walls, so Iin theory there should be no drafts, but we all know the quality of "pro" work these days.
Single story home?
 
Messages
397
Location
Peace valley, Missouri
A blower door test will tell you how tight the house is. A lot of utility company's offer this test under a energy audit mine charged $50 and with the audit receives more that $50 of stuff. Light bulbs, caulking & weather stripping.
 
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14,477
Location
...
Originally Posted by SatinSilver
Originally Posted by KrisZ
These thermostats were all installed on internal walls, so Iin theory there should be no drafts, but we all know the quality of "pro" work these days.
Single story home?
Good point. I would check the attic space and how the insulation has been laid.
 
Messages
9,373
Location
Canuck living in California
Thread starter
The house is two story and there are no drafts inside the house that I can feel at least. The wall that the thermostat sits on is next to the stairs and under the stairs we have a pantry and all of it attaches to the garage wall. I'm guessing the wall cavity is not insulated at all and some air from the garage enters it. Again, I don't feel any drafts when walking barefoot etc. so it's not affecting the living space, but that hole for the wires had an effect on the thermostat.
 
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