The two most common guidelines I've seen for thermostat placement is: don't put it on an outer wall, do put it in a central part of the area to be regulated. The first is certainly a good idea, but the second leaves out a lot of important considerations.
Whoever built my house put the upstairs thermostat in a central location... in the upstairs hallway at the top of the stairs. This is a terrible location, because:
- people are only rarely in the hallway
- there are no vents in the hallway
- cold air flows down the stairs to the bottom floor
- hot air flows up the stairs from the bottom floor
When the bedroom doors are closed at night it's virtually impossible to keep the rooms at a comfortable temperature. They get too cold in the winter, because the thermostat is warmed by air from downstairs and the bedrooms are cooled by their outer walls. In the summer, the A/C just runs continuously because none of the cold air reaches the thermostat, and what little gets into the hallway just flows down the stairs.
Two weeks ago I spent a day investigating what it would take to relocate the thermostat, but the difficulty is prohibitive. The thermostat wires come up from the basement, through the ground floor walls, to the second floor. Ugh. I was hoping they came down from the attic, but no such luck.
So, yesterday I ordered a Venstar Wireless thermostat sender and receiver set. Theoretically I'll install the receiver at the existing thermostat location and put the sender in my bedroom. The sender has a thermometer on it, and will tell the receiver when my room is the right temperature. The set cost $210 with shipping, but if it keeps my A/C from running all night I'm sure it will save me money over the course of the summer.
Anyone have any experience with these? I couldn't find many reviews, and it didn't seem like wireless thermostats in general are very widely used.
I have a similar situation, Michael. All the cold air tumbles down the stairs, so the upstairs rooms all have very different temperatures, depending on which doors are open or closed, and which window shades are drawn.
A few years back I bought a modern system with three different thermostats controlling three different regions of the house. It all seemed very fancy, until I realized that each zone still only got one thermometer. Why? How expensive can a wireless electronic thermometer be? It doesn't require advanced computer science to average multiple temperatures.
I hadn't thought of an aftermarket kit that would supply the rather simple electronics to make the system run better. My biggest worry is whether a given thermostat will work with my HVAC system. I don't really need a new thermostat; I just need more thermometers feeding data to it.
BB: I'll let you know how this one works, I'm going to install it this weekend.
I haven't seen any models that average temperatures from multiple inputs, though.
Ok, so the new wireless thermostat draws more voltage than my old thermostat, which caused a relay on the control board of my furnace/blower to switch on and off rapidly, eventually locking closed. So, today I'm going to replace the control board and connect a 250 ohm 10 watt resistor between the common and heat lines to boost the voltage. Theoretically that should solve the problem.