Types of HVAC Thermostats | HVAC Control There are many different types of thermostats. Thermostats also have various levels of complexity. Below is a list of the basic thermostat types. As we have time we will update the list to make sure it is as comprehensive as possible.

  • Non-Programmable Mechanical Thermostats – Many of these thermostats are the mercury bulb type which uses mercury to make contacts to energize the heat or cooling. Mercury is a highly toxic liquid conductive metal and needs to be handled with care. Human exposure to mercury is hazardous and if the bulb containing the mercury is broken great care should be taken to clean it up and dispose of it properly. Additionally, when the thermostat is replaced the old mercury type should be disposed of at an authorized disposal agency. Some mechanical thermostats do not contain mercury but use a calibrated magnetic strip and a bi-metal spring. These thermostats are effective but not as popular as the mercury type. Most of the non-programmable mechanical thermostats can be calibrated with special tools. It is recommended that only a qualified HVAC Technician perform these calibrations. The non-programmable mechanical thermostat comes in many different varieties for many different applications.

Types of HVAC Thermostats

Types of HVAC ThermostatsTypes of HVAC Thermostats

  • Non-Programmable Digital Thermostats – Non-Programmable Digital Thermostats are typically completely solid-state. They use a solid-state temperature sensing device called a thermistor to sense the temperature inside the dwelling and then uses a circuit board and user settings to energize the equipment. These thermostats are often easy to hook-up as long as one has a basic understanding of HVAC electrical control wiring. It is best, when one wants to replace the thermostat, to have a professional HVAC Technician replace it as you will be guaranteed to have the job completed quickly and efficiently plus you will not take the risk of causing electrical problems from mis-wiring errors.
  • Programmable Digital Thermostats – These types of thermostats offer basic functions for programmable thermostats all the way up to a complexity level that offers multiple functions and settings for a whole range and combination of HVAC equipment. Some programmable thermostats can be very difficult to program while are other programmable thermostats are easy to program and understand. It always helps to understand basic thermostat programs and additionally to read the instructions which came with the thermostat.
  • Programmable Mechanical Thermostats (non-digital) – these types of thermostats are very old but there are a few still around. It is highly unlikely one can find a programmable mechanical thermostat for sale at any local HVAC or hardware store. Using a mechanical timer and various switches and manual user settings this thermostat offers rudimentary functions for a programmable or setback thermostat. These types of thermostats typically used a mercury switch to complete the circuit. Therefore they have mercury inside of them. Many states have banned the sale of mercury switch thermostats and nearly every state has laws concerning the proper disposal of any product, including thermostats, that have mercury inside them.
  • Data Logging Thermostats - these types of thermostats record the temperature over time intervals for maintaining a record of the temperature. These types of thermostats are generally used by technicians for troubleshooting issues over a period of time to find irregularities and hot or cold spots in a certain area. They are also used by the food industry for transporting their products to ensure the proper temperatures were maintained during the transit. This ensures the food is safe and did not spoil at some point during the transit because it reached an unsafe temperature for that particular product. These types of thermostats can be either digital or mechanical.

Types of HVAC Thermostats

If one does not have the instructions which came with the thermostat the internet is a wonderful resource and one can find the instructions for many thermostats online by using a search engine to search for the manufacturer’s name, thermostat model number, and type of thermostat.

Types of HVAC Thermostats - Additionally, before shopping for a thermostat it is important to know what kind of HVAC equipment the thermostat will control. A heat pump thermostat will be different than an air conditioning system with a gas furnace. Also, all thermostats have anticipators in them. Mechanical thermostats require the heating anticipator to be manually set according to certain technical specifications. Always read the instructions and if you are not absolutely certain you can safely and efficiently complete the job call a professional HVAC technician to install a new thermostat.

Types of HVAC Thermostats

Types of HVAC Thermostats

Types of Thermostat

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