The Matrix Data Bank

For years, I have considered purchasing a new thermostat, so that I could integrate it into the Home Automation, and control it, easily..  So I have kept my eye on a few different solutions, but just recently, we needed some furnace work, and I was able to justify purchasing a new Venstar T1800, when I had the repairs done… First, the Venstar\’s are not that expensive, but if you are going to use it with an Insteon based Home Automation system, look for the Venstar Thermostat & Venstar Insteon Adapter bundle.  You\’ll save a few dollars that way, and it\’s noticeable… Second, the product is nice, while it doesn\’t have all buttons, slide switches, and other whistles my old thermostat had…  It works pretty darn well, and is pretty pleasing to set up. The thermostat supports dual fuel, multiple stage heat & cooling, and a variety of other features.  It supports \”fuzzy logic\” with heating and cooling, so if configured, it will attempt to have the house reach the temperature you request at the time you have programmed…  So in other words, it will turn on before your 6am scheduled time, so that the temperature will be \”right\” at 6am.  All this, and more… The size is right to, it\’s slightly smaller than my old thermostat…  Here\’s a comparison with a X10 3 button keypad, you can also see the Insteon Adapter at the bottom: The advertised features for the T1800 are:

• 7-day Programmable with up to 4 time periods per day, with copy command for easy programming
• Accepts humidification/dehumidification control module (Venstar part number ACC0430)
• Auto changeover, 3-stage heat, 2-stage cool for use with gas/electric, heat pump, electric & hydronic heat
• Configurable for manual changeover, also configurable programmable or non-programmable
• Adjustable deadbands and timers
• Control to, or monitor a second remote sensor
• 3 configurable outputs for maximum flexibility (MISC1, MISC2, MISC3)
• Extra 6th and 7th outputs (beyond our standard thermostat)
• Programmable Fan- adjustable 0 to 60 minutes each hour, with programmable start and stop times
• Smart recovery
• Display shows both heating a cooling set points and room temperature simultaneously
• All programming and set points stored in non-volatile memory, and are never lost in power failure
• Service UV lamp indicators
• Configurable programmable or non-programmable, also configurable for manual changeover
• Red/Green LED shows whether thermostat is calling for heating or cooling
• 5-minute compressor time guard and adjustable cycle limit, both defeatable for servicing equipment
• Outdoor sensor ready with high and low temperature of the day (wired or wireless)
• Thermoglow backlit electro-luminous display and backlit color coded keys and legends
• Accepts accessory IR Remote Control system (Venstar part number ACC0431)
• Accepts accessory EZ Programmer (Venstar part number ACC0432)

The best praise I can give this is that we haven\’t really noticed a significant difference between the Venstar & our older thermostat at this point.  Well, other than being able to reprogram the thermostat from the other side of the house, that is…. If you would like to explore the unit\’s features, and see how it operates, there is a simulator of the T1900 here… The Rev 2 Insteon adapter allows, access to:

• Cool Set Points
• Heat Set Point
• Mode Status Request
• Temperature Status Request (eg, the Temperature Readings from the Thermostat)
• Humidity Status Request, assuming you have the Humidity Sensor
• Fan Status Request, when in Automatic mode (After all, if it\’s at ON, you know it\’s running)
• Mode Control  (Heat, Cool, Auto, Off)
• Fan Control – Turning the Fan on, or switching to Auto
• Degree Format (F/C)

Pros:

• Can Integrate into an Insteon Home Automation Network (via the Insteon Adapter)
• Relatively easy front panel interface
• Indigo has built-in support for the Insteon Adapter
• Easy indicator showing if a heating/cooling cycle is actually active
• parasitic Power from the Furnace, so no batteries.  All data is stored in NVRAM, so no need to reprogram if there is a loss of power.  The Accessory port (eg. Insteon Adapter) also is parasitic, and requires no additional power.

Cons:

• Insteon Adapter (as well as phone adapter, etc) are add-on products
• Only one add-on product can be used at a time (eg. You can\’t tie into an Insteon network, as well as the Phone system, directly..)
• Unable to set the clock or built-in programming from the Insteon Adapter…  (It seems to be a glaring obvious overlooked feature, but without adding new Insteon protocols, I don\’t see how they could have done it…)
• Requires 6 wire running from Thermostat to Furnace (Technically 5 wire), it uses the common to supply power to the thermostat.  You can either run the additional wire, or use the 4 wire adapter…

Executive Summary:

Excellent Thermostat, and ties in easily to the Insteon network.  Well worth the cost, and effort.  It is more expensive than a stand-alone thermostat, but of course, your paying for the expandability.

Next Steps:

I am currently using the NOAA Weather script for Indigo, and I plan to devise some logic to allow the script to turn down or turn up the thermostat taking into account the weather forecast for the day.  I am also looking at adding some code to be able to display the heating and cooling readings from the thermostat.