HVAC System Replacement

Guide to Choosing a Thermostat

old-thermostatold-thermostat-1

Remember the old days when choosing a thermostat was easy? In fact it was easier than easy, there was no choice. When you got a new system in the 80’s you were the proud owner of one of these beautiful pieces of history. Not only did you get this amazing retro cover but should you pop the top off you were treated to the glory of mercury filled glass tubes and beautiful springs and wires.

We can probably safely assume if you are reading this article you are not looking to relive your glory days by incorporating a museum piece into your home comfort system. So let’s review the different options currently available.

Please note: You will need to know what type of system you have when choosing a thermostat.
Identify if your home is fitted with 1 Stage, 2 Stage, Direct Line Voltage, 24mV, or Zone heating and cooling to determine which thermostat will be compatible.

  • Works with 1 Stage heat or cool: For use where you have separate heating and air conditioning units
  • Works with 2 Stage or multi-stage heat or cool: For heating or cooling units that have a high and low speed
  • Works with Direct Line Voltage: 110 or 240 direct current power source used in some older homes to power the thermostat
  • Works with 24mV: For use with a fireplace, floor, or wall furnace
  • Zoned HVAC: Heating and/or cooling is individually controlled in different areas from the same HVAC system

Your Basic (Non-Programmable) Thermostat

honeywell-thermostat

Fortunately for many people looking for simplicity it is still possible to get a modern variation of the basic thermostat. There are countless options available to you. The basic thermostat is all digital, which makes it more accurate and reliable – and fortunately for the environment, it doesn’t contain any liquid mercury.

Operations

Just as you would expect, the operations are limited to basic thermostat functions.

  • Modes: Off, Cool, Heat, Emergency Heat
  • Temperature Set: Use the up and down arrows to set the temperature to your desired comfort level.
  • Fan: Off, On, Auto
  • Wifi: Available in some versions

 

System Compatibility

This basic thermostat will work with your normal combination A/C and furnace systems as well as heat pumps. On a heat pump system the electric heat strips are manually activated with the emergency heat mode, not automatically based on a temperature set point like more advanced thermostats. This thermostat will not work with higher end equipment that includes 2-stage and variable speed equipment. You can learn more about your system type and identifying your equipment here.

Examples and Cost

Generally found under $50:

Honeywell Digital Non-Programmable Thermostat

Emerson Digital Non-Programmable Thermostat

 

WiFi Programmable Thermostats

wifi-programmable-thermostatBefore we get all the way to the “smart” thermostats like the Nest and Ecobee there is a thermostat option that is like a bridge between basic thermostat operation and the truly smart thermostats with the added function of WiFi control. These thermostats are still relatively simple but allow you to program the thermostat to adjust the comfort inside your home based on a schedule.

Operations

Operations are similar to the basic digital thermostat with the addition of a programmable schedule.

  • Modes: Off, Cool, Heat, Emergency Heat
  • Temperature Set: Use the up and down arrows to set the temperature to your desired comfort level.
  • Fan: Off, On, Auto
  • Programmable Schedule: Operation will vary from model to model but typically includes 7 day scheduling with wake, daytime, and night settings plus an “away” mode for vacations or extended absences from the home.

 

System Compatibility

This basic thermostat will work with your normal combination A/C and furnace systems as well as heat pumps. On a heat pump system the electric heat strips are manually activated with the emergency heat mode, not automatically based on a temperature set point like more advanced thermostats. This thermostat will not work with higher end equipment that includes 2-stage and variable speed equipment. You can learn more about your system type and identifying your equipment here.

Examples and Cost

Generally found under $50 or under $150 with WiFi. Note, links may not function if 3rd parties change their websites or discontinue products. These links are for example purposes only. You can always search Google.

 

Wifi Smart Thermostats

The Cadillac of thermostats are the WiFi smart thermostats. The most well-known of this type of thermostat is probably the Nest ®. The Nest burst onto the HVAC and home automation scene in 2011 with the concept of the “learning” thermostat for the purpose of revolutionizing comfort and energy efficiency. The concept of a digital smart thermostat was not new, however. Several other manufacturers had similar products albeit without the same sexy form factor and interface. In this section we will break down the main features and options and some of the pros and cons of a WiFi smart thermostat.

Operations

One of the major differences in the smart thermostats and the digital programmable thermostats is the interface. Due to the popularity of the nest, all of the manufacturers of smart thermostats have followed suit with sexy form factors and slick digital interfaces.

Learning Mode

The Nest introduced the concept of the “learning mode.” The thermostat can sense your normal patterns and behavior and adjust to make the home comfortable when you are home and save energy when you’re not. There are a wide variety of opinions about whether this function really works well for the homeowner and/or saves as much energy as advertised. Heating or cooling a home from a higher or lower temperature uses almost as much energy on a short term basis as maintaining a fixed temperature. The exception for this is when you will be gone for several days at a time. Many homeowners have an expectation that their home will instantly change temperature when the thermostat is changed. Heating and cooling systems are carefully sized to the dwelling and the higher or lower the temperature is outside the longer it will take to bring the temperature to the desired set point. It’s not unrealistic for it to take an hour to move the temperature 1-2 degrees in extreme hot or cold conditions. For these reasons, we suggest you purchase your smart thermostat with learning mode with some skepticism. If works well for some and not for others — and a homeowner’s expectations, house and equipment are all major factors.

Mobile App

The mobile app is universally billed as a huge step forward in convenience and innovation. The best manufacturers spend lots of time working on the user interface (UI) design to make their products as easy and enjoyable as possible to operate and most have largely hit the mark. Being able to remotely change the settings of your thermostat to put it in away mode after you’ve already left for vacation or simply check the indoor temperature for your pets or loved ones are hugely convenient. Imagine being able to warm up your workshop or cool down a sunroom you plan to use before you head home from the office. In addition to making comfort adjustments conveniently from nearly anywhere, setting up schedules and adjusting settings is a whole lot easier to do from an app than it is standing in front of the thermostat cycling through endless menus. In fact, one of the most irritating parts of using a standard digital programmable thermostat is setting up the schedules especially when copying from day to day.

Notifications and Alerts

Another great feature of smart thermostats are notifications and alerts. Alerts can be as simple as letting you (and your HVAC service company if you choose) that there is a problem with your system. These can be setup for a variety of delivery methods and can show up on your smartphone as an alert or often via email or text message. Routine service notifications such as the need to change your filters are often built-in features.

Voice Control

Having the ability to control your thermostat from your Alexa, Google Assistant or Homepod is a cool feature to many people. Most of the smart thermostats now integrate with the ability to control by voice but you will need to check each offering carefully to be sure all the features you are looking for are fully supported.

 

System Compatibility

System compatibility will vary from model to model but smart thermostats are much more likely to cover all equipment types and variations. One exception you will need to pay attention to is if you have premium equipment that is controlled by a manufacturer specific thermostat. These premium systems may combine variable speeds and eco features in ways that require their own protocols and sensors to operate at their full capabilities or event to be compatible with factory warranties. If you have a premium system you should check with your HVAC service company before installing a smart thermostat.

Examples and Cost

There are some options currently in the $250 range: