The time is upon us where many of us north of Route 80 start to fear our upcoming heating bills. Like many other HAI enthusiasts I am reviewing my programs to figure out how to squeak every ounce of efficiency out of my system. As I started reading my program from last year, I started thinking about the sheer number of programming approaches you can use to set temperatures with an HAI controller. I thought it would be helpful if I explain several of them and the benefits associated with each one.
Use the schedule in the thermostat:
Omnistats have a built in time schedule. Typically this is disabled when connected to a controller; however, if you want to use an Omnistat stand-alone or if your customer is used to the schedule being in the thermostat, it is an option. This is probably the least efficient approach because you are not taking advantage of the HAI controller. When setting the schedules remember that, “Whatever happens last wins” so if you send a command from the controller, and a time schedule comes up in the thermostat, the thermostat is going to follow the time schedule. It is my recommendation to turn off the Omnistat internal scheduler when using an Omni or Lumina controller.
Use the Occupancy mode in the thermostat:
Starting in the RC1000 and RC2000 HAI added a great alternative to the time schedule. Instead of using a time scheduler in the Omnistat, you can store the setpoints for the arming levels (or modes in a Lumina). Now the setpoints stay in the thermostat and the correct setting is chosen each time the system is armed. This new feature is called Occupancy Mode. We have many dealers that love this approach because it keeps the temperatures in the thermostat which is a logical place. It is easy to teach and understand. There are a couple drawbacks to consider. First, the settings can’t be read or stored in a PC Access file so a customer can make changes that can only be modified at the thermostat. Secondly, Occupancy Mode is only going to be effective if the system is armed on a regular basis. Personally, I really like this approach because it places the settings in a logical place for the homeowner. It is especially effective if a customer regularly arms their system. Just remember, like the thermostat scheduler, “Whatever happens last wins” so it is not good to mix controller programming with Occupancy Mode. It is best to choose one way or the other.
Send setpoints to the thermostats based on time or arming status:
The most traditional approach to energy management is to use the automation programming in the controller to send setpoints based on time and/or arming status. This by far is the most flexible and powerful approach to controlling thermostats. The thing to remember is that you should turn off the scheduler and Occupancy Mode in the thermostat. When you don’t, troubleshooting can be confusing because you will not find the answers in your program. Again, “Whatever happens last wins” so the scheduler can often cause temperature settings to inexplicably change. In reality, it is just the schedule running, so we always recommend turning the schedule and Occupancy Mode off.
Use user variables to adjust temperature setting:
As of 3.0 firmware, HAI cured the biggest hurdle in temperature control. Back in the old days (2.16 and earlier) all of the temperature settings were stored in the system programming. That is fine if you know how to program and HAI, but for non-programmers, it was a challenge. Now things are MUCH better. If you don’t use user settings, it is time to give them a try. Simply put, User Settings move values that are often changed from the system program to the top level interfaces like touch screens and Snap Link. This is the way I control my house. Instead of saying “WHEN 6:00 AM Upstairs Thermostat HEAT 68 DEGREES” it is better to use User Settings. Now the program looks like “WHEN Wake-up Time Upstairs Thermostat HEAT Wake-up Heat”. “Wake-up Time” would be created as a User Setting ‘time’ and “Wake-up Heat” would be a ‘temperature.’ It does add a couple steps the first time the program is written but there is a huge advantage. I can change the settings from my iPhone, iPad, PC, or Touchscreen in a second! You can also review all of the settings on one screen. Better yet, so can your customers. If you have not used User Settings, you should check them out. Once you use them, you will not place hard values in any of your HAI programs anymore.
While writing this article, I spoke with some of my colleagues to learn how they approach temperature control and the one that I have not played with in my own home is temperature setback. It certainly is worth consideration and may be the best approach for heat pumps and radiant heat. The way it works is that you manually control the thermostat when you are home. You then use programming the set the thermostat back based on arming or a late night time. For systems that should remain a steady temperature, consider small setbacks like 2 or 3 degrees. You then push the setting forward on disarm and a morning time. One of the big advantages of this approach is that it is based on the user’s perceived comfortable temperature which can vary throughout the year.
One thing is for certain, HAI offers installers and users more approaches towards temperature control then any other system on the market. By knowing each one of these approaches you can better serve your customers to determine an approach that works with their lifestyle. With that said, I have got some more programming to do…..the snow has started flying in the Pocono’s (I’m not kidding!).