Do I Use RH or RC on Nest Thermostat? [Detailed Guide]

Are you here because you’re unsure whether you use Rh or Rc on your Nest thermostat?

It totally depends upon your thermostat. Note that the Rh indicates the heating unit while Rc indicates the air conditioner. The control centers for the heating and cooling system may be separated but controlled by a single thermostat.

Keep reading to learn about Rc and Rh, such as what it is, their function, and much more.

do i use rh or rc on nest thermostat

Do I use Rh or Rc on Nest thermostat?

Knowing about your appliances’ internal structure is essential for easy work done, especially when something goes wrong. But, unfortunately, it’s pretty confusing to just find out about it without any background knowledge.

The Rc and Rh terminals are the positive connection ports for 24- the volt cooling and heating power supply. So, if you have a supply of 24 V AC, there will be a jumper from the Rh to the Rc.

However, if two power sources are available, then the heating appliance would be connected to the Rh while the cooling to the Rc. Therefore, the red t-stat wire is present at the terminal for such thermostats.

RC vs RH thermostat

What is Rc on the thermostat?

Every thermostat has Rc and Rh wires to obtain the required temperature within the system to keep it functioning. The Rc and Rh may or may not be connected. If yes, then there will be a red wire indicating the jumper between them.

The Rc stands for red cooling. Comparing the Rh wire, it activates the thermostat but supplies the cooling system. So, for its connection, if you have all three wires, such as Rh, Rc, and R, you need to connect the Rc wire to the Nest thermostat R’s connector.

What is Rh on the thermostat?

The Rh stands for red heating. This wire activates the heating system of your air conditioner to maintain the optimum temperature within the system. Just like the Rc wire, it also uses 24 V AC to function well.

As you know, the red indicates the harmful nature of the equipment. However, note that the red here in this name doesn’t represent any such thing. In addition, this wire may or may not be red depending upon the device, as there’s no standard rule for color here.

Also read: How to fix the nest e74 error

Functioning of Rc and Rh wire

To understand the functioning of the Rc and Rh wires, you must know what colors usually represent them.

The red wire specifies the power of 24 V for the Rh and Rc, yellow for the Y terminal of the cooling system, white for the W terminal of the heating system, blue for the C (common) terminal, and green for the G terminal for the fan.

Each thermostat on your air conditioner connects to the furnace, which contains the heating and the cooling system. Such connection is by the Rh and Rc wire to operate the heating and cooling systems efficiently.

Moreover, in some systems, the Rh may be absent; instead, the R wire may be present. Here, the R wire functions similarly to the Rh wire in controlling the heating system. The same goes for the Rc wire as well. So, we can say that the R wire is similar to the Rc or the Rh wire.

Although these wires may seem dangerous due to high power supply, such as 24 Volt, they’re not. However, precaution is the best safety measure, so always turn off the unit before replacing or working on these wires.

Some other relevant wires in the Nest thermostat:

To properly understand your Nest thermostat’s functioning, we suggest you know about the other relevant wires of the Nest thermostat besides the Rc and Rh wires.

Below are some of the other relevant wires of the Nest thermostat:

1. C wire

C wire, also known as the common wire, is present in almost all thermostats. It supplies the main power to all the equipment, enabling the thermostat to function. However, some thermostats may be absent, especially in the ones that get the power from the already present wires.

The main difference between them and Rh and Rc wire is that it supplies power to the thermostat while the Rc and Rh wire supply to the cooling and the heating system, respectively.

2. G wire

The G wire operates the blower fan. It’s not the live wire. Therefore, it’s the safest wire of all.

This wire lets the blower fan push the warm or cool air outside the vent. So, if you don’t have a G wire, this function would be affected; thus, no air will go out of the unit.

3. E wire

The E wire is present in the heat pump, which increases the heat in the surrounding. It functions when your room is super cold, and you don’t have any auxiliary heat pump. So, normally the E wire would not function until needed in any emergency.

4. Y/Y1/Y2 wire

All the wires with Y in their name are connected to the cooling system to increase the air to be pushed out more efficiently. Some systems either have just Y wire, or they may have Y1 and Y2 both.

5. W/W1/W2 wire

These wires are responsible for the cooling system. These wires signal down the heating mechanism whenever your thermostat is super cool, and you aim it to lower a bit. You can find it in single or two wires like the Y wires.

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The most important wires for your thermostat are Rh and Rc wires, which control the heating and cooling systems. Depending upon your device, you may have both wires connected to a single 24 V power supply together or separately. If together, there will be a jumper connecting the Rc and Rh wire.

Read this blog to clearly understand Rh, Rc, and other essential wires on the Nest thermostat. We have discussed their functioning and uses for you.

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