The thermostat is the controlling unit of your HVAC system. It is the switch that allows the unit to come on and off according to the temperature setting. Older thermostats were known as mercury switches. This switch was mounted on a thin copper strip that was designed as a coil. This copper would expand and contract allowing the mercury switch tilt in one direction. The mercury inside would be the metal that would activate the switch when it arrived at a certain point. These types of thermostats work fine and in some cases are still working in many homes. If you have this type of thermostat you may need to consider upgrading to a newer thermostat.
When deciding to replace your thermostat you need to make sure you choose the correct fit for your system. Most of the HVAC systems will use a low-voltage thermostat control. There are several different types of programmable thermostats that are digitally controlled. The digital control is more accurate than the older mercury style. The temperature of your home is monitored digitally allowing for more accurate readings of the system. A programmable thermostat may not be your cheapest option but it will save you money by cutting the energy cost over a period of time.
Choose a digital thermometer with a 5-1- 1 or 24-hour setting. This will allow you to program your system to come on and off at different times of the day. You can also set for different temperature and time settings if you are going to be gone for a few days at the time. Some of the digital Wi-Fi thermometers that are available today are designed with apps allowing you to control your HVAC system for your smartphone or tablet.
Some of the more expensive digital systems Have a PID controller that will decide when to start the system based on the current temperature and a desired temperature at a desired time. This simply means that if you want to arrive home at a desired time and you want the temperature to be at 68 degrees this controller will allow the unit to come on earlier allowing for the temperature to reach the desired setting before you arrive home.
There programmable thermostats are easily installed by following the color coded instructions that come with the package. Most of the thermostats have the letters beside the terminals to attach the correct color wire. With most of these controllers being powered by batteries the only wires that need to be installed is the thermostat wire that runs from your HVAC unit to the thermostat. Replacing these thermostats will be an easy project for any DIY person only requiring a simple screwdriver and wire cutters.
Digital thermostats will eventually pay for their selves in fuel savings. Tests have shown these thermostats will help you to save 30% over the standard mercury thermostats.