Heating and Cooling Thermostat Types

Honeywell Touchscreen Thermostat

There are many different heating and cooling thermostats available on the market for someone to purchase and they range in price from $30.00 all the way up to $300.00 or more depending on the bells and whistles that come with the fancier heating and cooling thermostats.

A word of caution, before you go out and spend any money for a heating and cooling thermostat, make sure you understand the type of heating and cooling equipment you have in your home or business.

Thermostat RC and RH Explained

Heating and cooling systems vary widely and it is important to match the right heating and cooling thermostat for your specific heating and cooling system. For example, a person who has a straight air conditioning system installed with a hot water boiler system may have separate control transformers. There will be a control transformer for the air conditioning system and one for the hot water boiler system.

In this case it is important to purchase a heating and cooling thermostat that has two terminals to separate the two different circuits or know that you have an isolation circuit wired into the system that isolates the control voltage of the hot water boiler from the control voltage of the air conditioning system. Some thermostats come with an RC and RH terminal for this purpose. Instead of having an isolation circuit wired at the boiler or air conditioning system the thermostat provides this isolation for you.

This means when it is time to wire the thermostat you will have two red wires, one for the hot water boiler or heat and one for the air conditioning system. It is important that you know which red wire goes to which system or the heating and cooling system will not function properly.

Thermostat Types

Heating Only Thermostat - this thermostat is common for homes and businesses that have only a heating system serving the building or they have separate thermostats for heating and cooling. Many heat only thermostats do not have any switches to turn the system off. These thermostats only have a temperature selection dial to adjust the temperature. When you want to turn the system off you simply turn the dial all the way down to the lowest temperature. Many of these thermostats are the round Honeywell thermostats and are difficult to recognize except by the trained eye. This thermostat can be quickly upgraded to a combination thermostat by changing the sub-base.

Combination Thermostat

Cooling Only Thermostat - this thermostat controls an air conditioning system and can be found in many different styles. This is usually used when the heating system has its own thermostat. This thermostat usually has an on - off switch and a fan - off - auto switch for control of the fan. It is important to know that if you have two separate thermostats, a thermostat for the heating and a thermostat for the cooling system, that you make sure they are not on at the same time. To ensure this does not happen ever you can have a combination thermostat installed by a professional heating and cooling technician.

Combination Thermostat - this thermostat provides the multi-function ability to control both the heating and the cooling systems. These can be the mercury bulb type thermostats all the way up to the digital type thermostats which can hold a program for specific time and day control. There are differences in these thermostats. If you have a heat pump you need to purchase a thermostat specifically for a heat pump. If you have a gas or oil furnace with an air conditioner you need a specific thermostat to control the heating and cooling system. If you have electric heat with an air conditioning system you need a specific thermostat for to control your heating and cooling system. Some manufacturers make multi-use thermostats that can be used on any different combination of systems noted above. These thermostats have selector switches or dip switches which can be set for the type or combination of system which you have for heating and cooling.

The combination thermostat is the most used thermostat in homes and businesses today. If you do not have any understanding of wiring, thermostats, or HVAC systems it is best that you call a professional and let them install a new thermostat as many things can go wrong for not hooking the thermostat up properly.