Westar's WattSaver thermostat -- is it for you?

If you're a Westar Energy customer, you've receieved at least one mailing by now about their free WattSaver thermostats.  You may have a number of questions about them... I know I did!  I called and got most of my questions answered, then went ahead and got one of them so I could answer customers' questions myself.  Here's what you need to know:

  1. It is a full-featured, programmable thermostat, similar to what you would pay $35-$65 for at a hardware store.  There are separate programs for weekdays, Saturday and Sunday, and four temperature settings per day, and separate heating and cooling temperatures, for a total of 24 programmable temperature settings.  You can manually switch from heating to cooling or have the thermostat do that for you.  There's a backup battery to get you through power outages.  The screen lights up when you touch it, or you can have it remain on all the time as a night light if you want.  It installs just like any other thermostat, so if decide you want to remove it and go back to your old thermostat, you can do that without calling Westar.
  2. It is wirelessly connected to the Internet by way of Westar's own private network.  It does not use your home Internet connection, nor does it use standard wi-fi signals that you can pick up with a computer.  The main reason it's networked is so that Westar can turn down your air conditioner during peak demand periods to save them from wasting a lot of energy starting up an extra generator.  There are very specific limitations to how often they can do this and for how long -- it's all in the contract.  You can also reprogram the thermostat over the Internet -- for example, if you're going out of town and forgot to turn down the heat, you can do that from the airport, and turn it back up again when you're on your way home.  There are additional features in the thermostat's manual that Westar hasn't yet implemented, such as the ability to review your past utility bills on its screen.
  3. Here's the catch: it's designed for use with new, efficient equipment that heats or cools the house slowly.  If you have an old furnace or air conditioner that is only all the way on or all the way off, and particularly if it's oversized for the size of your house, this thermostat may cycle it on and off more often than the equipment was designed to do, causing your equipment to wear out more quickly, kind of like a light bulb being flicked on and off over and over.  The thermostat has no way to adjust its hysteresis -- the temperature difference between when it turns on and when it turns off.  If you have it set at 68˚F, for example, it will turn the furnace on while the temperature still reads 68˚F rather than waiting for it to drop to 67˚F, and it will turn the furnace off again while the temperature still reads 68˚F rather than waiting for it to climb to 69˚F.  If you have newer, properly sized equipment, that's not a problem because it will take a while for the temperature to change.  But if you have old and/or oversized equipment, this thermostat may wear it out prematurely.

In short, I recommend the WattSaver program for homes that have fairly new, properly sized heating and cooling equipment.  If you think your equipment may be old or oversized for your house, you're probably better off with a traditional programmable thermostat for now.