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DerbyDad03 DerbyDad03 is offline
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Default Thermostat placement

On Jan 16, 12:26*pm, Ken wrote:
Phisherman wrote:
On Fri, 16 Jan 2009 07:37:13 -0600, Ken wrote:


* * * *I have a Tri-level home with two separate furnaces and air conditioning
units. *One unit controls the lower two levels and another the upstairs
level. *The lower unit has a thermostat located at the bottom of the
stairway leading to the upstairs, and the upstairs had a thermostat at
the TOP of those stairs.


* * * *Ever since I moved into this home (30+ years ago), I have had uneven
heat/cooling of the upstairs rooms. *When the heat or cooling would go
on, the room temperature would be some 8-10 degrees different from what
the thermostat was reading. *Eventually the thermostat would be effected
by the temperature change and would turn off the heat or AC. *The only
problem was it ran much longer when it would come on, and the uneven
room temperatures.


* * * *Recently I read that a thermostat should NOT be installed at the top of
a stairs. *Obviously heat from the downstairs would tend to rise and
impact on the upstairs thermostat when cooling was taking place. *The
question I have is why the uneven control while heating is taking place?
*One would think that when the upstairs furnace was on, the stairs
would have little or no impact due to the heat rising up?


* * * *Finally I decided to do something about this uneven temperature
problem. *I took a digital thermometer and looked for a location in the
same hallway upstairs that was more representative of the true
temperature. *That is, much warmer than being sensed by the thermostat.
*After relocating the thermostat some 10 feet away from the stairs the
temperature is much more even. *I am very happy with the result.


* * * *My question is this: *I can understand the impact of the stairway on
cooling the upstairs, but why did the heating of the upstairs respond
poorly as well? *I feel I am overlooking something simple, since I know
it DOES impact it by the results I achieved.


I have a large central open staircase. *At the top of the stairs is a
cold air return and 4 feet about it is a thermostat for the upper
floors. * The first floor thermostat is about 4' above the bottom cold
air return. *The two systems work independently, but both themostats
are on inside walls. *I grew up in a house where the thermostat would
kick on when the front door was opened during the winter. * You may
want to have the blower on all the time, or ceiling fans, or an extra
fan to circulate the air. * * All homes have hot-cold pockets, but you
can minimize that with fans, draperies, furniture, etc.


* * * * First I would like to thank you and others who replied with helpful
comments. *As I wrote in my original message, moving the thermostat
improved the situation dramatically. *I am sure the fact the old
location was directly above the stairs was largely responsible for its
poor performance. *It is easy to visualize how the warm air of the lower
floor would travel up the stairs and impact that thermostat when cooling
was taking place. *What puzzled me is why there was still a problem when
furnaces were being used. *One would think that the heat rising from the
lower floor would turn off the upstairs thermostat earlier, rather than
later.

* * * * As Ed suggested, there has to be air currents effecting the old
location because moving the thermostat's location solved the problem. *I
guess I should just be happy the problem was solved, but I like to
understand WHY something happened. *Thanks.- Hide quoted text -

- Show quoted text -


Do you know what is behind the wall where the upstairs stat was
mounted?

They say you shouldn't mount a stat on an outside wall since they are
typically colder than the air in the room. Is it possible that the
wall itself could be affecting the stat?

At the top of my stairs I have an access panel for the tub. This
cavity is open from the basement to the attic and typically colder
than the surrounding air.