The basic approach is to buy a switching relay that is operated by the low-voltage thermostat and that in turn turns on the 120VAC or 240VAC heaters. You replace the line voltage thermostat with the switching relay, then add low voltage wire from a transformer to power the Nest or other low-voltage thermostat.

Can Nest thermostat work with line voltage?

The Honeywell Lyric, Nest and other smart thermostats are designed to work with central home heating systems. Those are controlled by low voltage thermostats, which use 24 volts. Electric baseboard and fan heaters work with line-voltage thermostats, which can be either 120 or 240 volts.

What are the major differences between the line and low voltage thermostats?

A line voltage thermostat ranges from 120 to 240 volts. It uses more power than low voltage thermostats because it delivers power directly to your heater. Line voltage is more commonly used with radiant, convention, or resistance heat sources. If you have baseboard or wall heaters, you likely have line voltage.

What voltage does a low voltage thermostat operate?

The low voltage thermostat is the one found in most homes. Their voltage usage is much lower than that of line voltage thermostats, hence the name. Low voltage thermostats run off of voltage somewhere around 6-30, with 24 being the average.

Why low voltage operating controls are used in heating systems?

Low-voltage thermostats are smaller and cheaper to install and maintain, and the wiring does not need to have as high a voltage and power rating as their line-voltage counterparts. This is why low-voltage control circuits are favoured for central heating units.

Can I use a line voltage thermostat for low voltage?

Put simply — no. A low voltage thermostat like Nest or ecobee is not compatible to replace a line voltage thermostat for electric heat. Line voltage systems deliver power directly to your heating system rather than powering an intermediary furnace like a gas burner.

Will a line voltage thermostat work with low voltage?

A low voltage thermostat will not work with line voltage wiring.

How do I know if I need a low voltage thermostat?

A quick recap ,if you are looking for a thermostat: if you are using a Cadet or other radiant heater in your home, you will need a line voltage thermostat. If you are using a central system, you will want a low voltage thermostat.

How do you wire a low voltage thermostat?

Quote from the video:
Quote from Youtube video: All right and snug down the other one where you have this connector at which connects it from R to R six you want to have a decent thermostat.

Why are line voltage thermostats less accurate than low voltage thermostats?

Why is low voltage thermostat normally more accurate than a high voltage thermostat? Because unanticipated thermostat cycles shows system overshoot causing larger temp swing low voltage is acts faster.

What is the difference between low voltage and line voltage?

Low voltage lighting systems uses 12 or 24 volts to power its fixtures. As line voltage systems come in at 120 volts, low voltage systems require a transformer so as not to immediately burn out the bulbs. The transformer itself needs to be installed relatively close to the light fixture in order to function properly.

How do you wire a line voltage thermostat?


  1. Attach a Wire Nut to Ground and White Wires. …
  2. Wire-Nut One Hot Wire to Bypass the Thermostat. …
  3. Attach the Line and Load Black Wire to Thermostat. …
  4. Push the Green, White, and Red Wires Into the Box. …
  5. Line Up the Screws on the Box. …
  6. Screw the Thermostat Into the Box. …
  7. Replace the Thermostat Faceplate.

What is a millivolt thermostat?

Millivolt Thermostats

Unlike low-voltage systems, they do not require a step-down transformer and are not connected to the household wiring system. Instead, they are self-powered by a special thermocouple device called a powerpile or thermopile generator that produces direct current (DC) electricity.

Is there a millivolt thermostat?

A millivolt heating system is commonly found in floor heaters and wall heaters that have no external electrical power source. Such heaters include gas-fueled wall heaters or gas fireplaces. This millivolt heating system can only be regulated by a millivolt thermostat.

How do I know if I have a millivolt thermostat?

Quote from the video:
Quote from Youtube video: To find out which kind you have simply remove your thermostat from the wall and just look at the wires that are connected to it it's not hard all you need is a screwdriver.

Can you use any thermostat with any furnace?

Know Your Equipment & Your Wiring

Not all thermostats are compatible with existing HVAC systems, especially smart thermostats! Some thermostats work only with furnaces and air conditioners, for example. Others may be designed to monitor heat pumps or multiple-stage heating and cooling systems.

How do I know if my thermostat is compatible?

Quote from the video:
Quote from Youtube video: Then select your country at the compatibility checker main screen tap get started then power off your hvac. System and remove the cover from your thermostat.

Can I use a 2 stage thermostat with a single stage furnace?

Yes, I meant to say any two stage furnace… Using a 2 stage thermostat will not harm the furnace. And because the control board is compatible with a single stage thermostat, the furnace will still operate both stages. The control board would, as you say, start the second stage after about 10 minutes.

Can you use any thermostat?

You’ll need to get a thermostat that is compatible with your system’s voltage requirements. Most thermostats work with low voltage systems. And the good news is, unless you have wall/floor heaters or an electric baseboard heating system, you most likely have a low voltage system because they are the most common.

Can smart thermostats ruin your furnace?

Smart Thermostats Can Short-Circuit Old Furnaces

If the smart thermostat takes too much it can short-circuit the furnace. Overtime, this can lead to serious damage and even complete failure of the furnace. However, this is almost exclusively a problem for old furnaces.

Can I install any thermostat in my house?

Purchase a replacement thermostat that will work with your system. Review the compatibilities listed on the packaging of the replacement thermostat. Most replacement thermostats are compatible with all common systems. However, if your system is unique, finding a replacement thermostat may be difficult.