Updated November 29, 2007 12:00 PST
Stay Warm This Winter With Z-Wave Thermostats
By David Powell
You most likely want to stay warm this winter and one way
to keep control of your thermostat is with some of the currently
available Z-Wave enabled thermostats. There are, however,
a few "gotchas" to look out for.
ZTT000 is a thermostat that I currently have installed
in my home (see Figure 1). It's designed to work with all
types of air conditioners including heat pumps. The thermostat
was originally designed for RVs and mobile homes and now
contains a Z-Wave transceiver. It's powered using the existing
24Vac, which your existing thermostat uses to control the
relays in your system.
Typically programmable thermostats are battery powered
to reduce the heat put off by the power supply. So as you
might imagine the ZTT000 does put off some heat, which affects
the temperature reading. However, this is only an issue
when you are changing setting on the thermostat. After a
few seconds of inactivity the heat from the power supply
is gone and the thermostat functions normally. Installation
of this thermostat is fairly easy but you will need to do
a little research or hire a professional. Installing a thermostat
wrong will likely cause your AC or heater to malfunction.
The ACT ZTT000 is now listed as obsolete and a replacement
ZTT010 is listed on ACT-Solutions website as coming
soon. Hopefully ACT will fix the issues listed above.
Next, on my list of Z-Wave enabled thermostats is the RCS
TZ16 from Home Controls (see Figure 2). The control
unit supports up to two stages of heating and cooling for
both standard systems and heat pump systems. This Z-Wave
thermostat seems to be a crowd favorite in the DIY community
but that may change when some of the newer units ship. The
RCTZ16 thermostat consists of three parts, a Wall Display
Unit (WDU), the HVAC Control Unit and the ZWBT Z-Wave Thermostat
The Wall Display Unit offers functions like a traditional
thermostat and connects to the Control Unit by a four-wire
cable. The Control Unit connects at the HVAC system using
the standard thermostat connections and provides the thermostatic
temperature control of the system. The ZWBT provides connection
to your Z-Wave network. This is easily retrofitted into
existing homes using the existing thermostat wiring.
Finally, a company called Zykronix
has a product called the Magic Box, which includes controls
for most HVAC systems, including heat pump versions. Analog
inputs can interface to powered or unpowered sensors while
four damper outputs provide for multiple zone control. Along
with the Z-Wave wireless network, the MagicBox has an RS-232/RS-485
serial interface and four infrared LED driver outputs, which
can be used to control remote devices. On board temperature
and humidity sensors are also available.
In some ways, you might be better off sticking with your
existing thermostat through this winter while the manufacturers
work to get these new products on the market. But if you
need something now there are two options available. The
RCS RCTZ16 from Home Controls, which is currently shipping
and the ACT ZTT000, which you will have to find in stock
since they are discontinued.
Coming up, HAI, a privately held manufacturer of integrated
automation and security products, recently announced its
new Z-Wave enabled thermostat called the RC-80BZ
(see Figure 3). One thing to consider about the HAI is that,
according to the company, it's for single-stage heating
and cooling systems, non heat pump. Although I need to dig
into this a little more, I interpret that statement to mean
that the thermostats are not to be used with heat pumps.
While you have only a few options for automating your heating
system this winter, there are definitely more on the horizon.
I'll be exploring this topic further in upcoming columns.
David Powell is the Technology Editor for ZWaveWorld.com