HVAC Supplies Blog

Thermostats are important devices in millions of homes around the world providing the necessary comfort indoors all year round. Basically, a thermostat is a device that adjusts your heating system to the preferred temperature.

There are plenty of thermostats out in the market to choose from. Some people still prefer traditional thermostats while some like their smart counterparts. Traditional thermostats are still very capable of catering to your basic heating and cooling needs but there is no denying that smart thermostats offer a lot of conveniences since you can access them remotely keeping your house in perfect temperature while you are away. Most of them also allow you to heat specific sections of your home.

What Is Line Voltage?

Before we dive into line voltage thermostats, it is important to understand the term “line voltage”. Line voltage refers to the amount of voltage that is going through an electrical socket that then is used to power all our electrical appliances and devices. 

Most electrical equipment will function at 120V or 240V which facilitates the way we use our appliances: just plug it in, and turn it on with no effort. When your home has line voltage wiring, it eliminates the need for any additional equipment such as transformers or extra hardwires. Line voltage thermostats, also known as a voltage thermostats, run on line voltage as well.

What Is a Line Voltage Thermostat?

A line voltage thermostat also referred to as high voltage thermostat, runs on direct line voltage and is commonly used to regulate baseboard heaters or any type of heating systems that work on direct electricity.

A line voltage thermostat often has two or four thick wires coming out of its back. If you want to know if your heating system is compatible with a line voltage thermostat, just check the back of your current one. If you have a line voltage system, the thermostat will have 2 or 4 wires coming out of its back. If it has more than four wires then your system is not compatible with line voltage and you should purchase a low voltage thermostat for your home instead.

Line Voltage Thermostats vs Low Voltage 
Thermostats

Line voltage thermostats run on direct line voltage while low voltage thermostats which run on fuel like oil, propane, gas or other sources. Between the two, low voltage thermostats are the more common type and are typically used for central heating systems.

Just like what the name suggests, low voltage thermostats run on low voltage (24 volts) and because of this, the installation process is relatively safe - in fact, many homeowners can perform it themselves without hassle. On the other hand, installation of line voltage thermostats are more complicated and often needs professional help. This is because you are dealing with high voltage wires that can potentially knock you down, burn you, and even kill you.

If you have appliances like baseboard heaters, radiant heaters, or electric room heaters, low voltage thermostats are not suitable for them and you should buy a line voltage thermostat for these appliances.

Single Pole vs Double Pole

Line voltage thermostats have two variety: the single pole and the double pole. The single pole line voltage thermostat has two wires coming out of its back while the double pole one has four wires.

In electronics, "pole" refers to the number of separate circuits that the switch operates off one circuit. That means that a single pole thermostat operates on one circuit which means that the power to the unit can only run in one direction. This is the reason why single pole thermostat cannot be turned off, it can only be turned to low. The only way to turn it off is to shut the power from the breaker. One the other hand, double pole thermostats operate in two directional currents and they can be turned off completely.

How Do I Know If I Have a Line Voltage Thermostat?

It is important to know if you have a line voltage thermostat. You must get to know your heating system and check the voltage of your thermostat.

Learn about Your Home Heating System

There are numerous heating systems available on the market, and finding the right system for your home widely depends on your location and the requirements of your heating system. For example, if you live in a much colder climate, you will need a heater that will cater to your heating needs. 

Your needs will be directly linked to how you are heating your home and whether you have a line voltage thermostat. If your home heater runs on electricity, then you most likely have an electric line voltage thermostat. On the other hand, if your home heating system requires ductwork and uses radiators, then you probably don’t have a line voltage thermostat.

Check the Voltage of Your Thermostat

To determine whether your thermostat is a line voltage thermostat, you should check the voltage:

• Voltage meter: Use a voltage meter to measure how much electric voltage runs through your thermostat. It is important to follow strict safety guidelines when using this method of investigation.

• Label: An easy and safe way to check your thermostat’s voltage is to simply read the label. If your thermostat is a line voltage thermostat, then the label will have some type of “high voltage” warning. The label typically will be visible and situated under the cover of high voltage thermostats.

Inspect the Wiring of the Thermostat

Another way to inspect your thermostat and identify your thermostat type is to inspect the wires. The wires of your thermostat are located inside a metal box called a “gang box”. If you can’t find a gang box, you might not have a line voltage thermostat. 

When looking inside the box, you should thoroughly examine the wires that connect to your thermostat. The different colors can be red, black, or white, and there could be 2, 4, or 6 small wires. It is important to turn off the power from the circuit breaker that feeds into your heating system and thermostat before touching the wires to avoid a dangerous situation.

Smart Thermostats

Tradition thermostats were able to provide comfort to countless of homes for many years and there is no denying that going “smart” is the new trend to not only in heating but in other home devices. Smart TVs, smart speakers, smart refrigerators, smart lights, and any other appliance you can possibly think of. This is due to the rising popularity of the idea of smart homes, where homeowners can control every home device they have through voice command and artificial intelligence.

That means it that it is now possible to turn on the lights, lock the doors or adjust the thermostat just by using your voice!

People have different reasons why they would want a smart home but mostly, going “smart” is a great way to make your home more energy efficient.

Line Voltage Smart Thermostats

Smart thermostats have been in the market for several years now but did you know that the line voltage variety became available to the public only recently? This is because one in ten homes in the United States makes use of them and due to the small market size, manufacturers didn’t bother to make them.

Thankfully, there are now several line voltage smart thermostats available for you to purchase from several brands

Why Go Smart?

If you have a traditional thermostat that still works well, you might be wondering why you would need a smart one. Here are a few reasons to consider buying a smart thermostat for your line voltage system:

• Minimize energy usage

Smart thermostats are made and designed to be energy efficient providing only the needed heat then turns off when the ideal temperature is already achieved thus reducing energy consumption. According to a study conducted by Nest, thermostats reduce energy costs; there is ten to twelve percent savings on heating and fifteen percent savings on cooling. That's about $131-145 in savings a year.

• Scheduling

Line voltage systems are typically multi-zone systems which means that each thermostat works independently from the other. But adjusting all of your thermostats every morning and night is tiresome. With a line voltage smart thermostat, you can schedule these daily adjustments at the same time using their app which saves you a lot of time.

• Remote access

You can schedule a temperature change remotely with a smart thermostat because they usually have apps that can be installed on your mobile device. Some doesn't have an app, but you can access your devices through a web console. That means if you are away from home for a long time, you can still adjust and monitor your devices no matter where you are in the world!

Line Voltage WiFi Thermostats

People usually avoid WiFi-enabled smart home products because they require more energy. But with line voltage thermostats, you won't have this problem since they are connected to the main line of power. With a line voltage WiFi thermostat, the device directly connects to your WiFi router allowing you to control your thermostat remotely from your mobile device.

Converts pulse width modulated signals into a four (4) or an eight (8) relay output. The DMUX features the following:

1. Multiplexes a single output to eight (or 4), reducing output point cost
2. 4 or 8 relay versions, each relay has N.O. and N.C. contacts (Form C)
3. Accepts a relay, dry contact closure, transistor or triac signal
4. Individual Hand/Off/Auto override jumpers are standard, switches are optional.
5. Use DMUX to control multiple valves, lighting contactors, or any on/off electrical or pneumatic (through e/p relay) load.

Its triac compatible. Has a removable resistance card. Converts Floating Point (digital up/down), Pulse, or Analog signals to Resistance.

The DRN3.1 incorporates features many requested. Converts Anal og, Floating Point, and Pul se Wi dth Modulated signals to a Modulating Resistance Signal, and mounts in a plastic snap track (provided). The DRN3.1 features:

1. No Wrap Around! Increasing the input beyond upper range will not cause the output to start over at lowest value
2. If your digital output is triac that's OK with the DRN3.1.
3. Output is electrically isolated from input. Minimizes connection problems.
4. Power LED and two signal LED indicators. You can tell at a glance what the DRN3.1 is doing.
5. Lose power? Its Fail-safe! Control reverts to original controller or a fixed resistance
6. Floating Point Input has 3 field selectable ramping times.
7. Offset is field selectable

See All DRN3.1 Products

Splitting a 4-20 mA Signal into Two Different Rescaled Outputs

Method #1: For individual rescaling of the two outputs use two (2) ARMs

The 1st ARM interface converts the 4-20 mA signal into a voltage (1-5 VDC) from the input impedance of the 250 ohm resistor. Therefore the 2nd ARM interface should be setup for a voltage input signal. If isolation is a concern in your application, please consider the AIM1 Analog Isolation Module with a similar wiring setup. 

Method #2: If the two rescaled outputs can be the same use one (1) ARM2

 See ARM2 Product

The temperature differential is not a new concept - we experience it every day. We experience it the moment we step inside a mall or the moment we step off a bus; you feel it the moment you step outside during winter from your warm and toasty house or each time you come into your home where your air conditioner is running after walking under the heat of the sun during the summer. All of these are good examples of thermostat temperature differential.

Temperature Differential Definition

Temperature differential, as the name implies, is the difference between two varying conditions in terms of their temperature. In HVAC terms, the temperature differential refers to the difference between the indoor and outdoor temperature values of the house. 

The Significance of Knowing the Temperature Differential 

The temperature differential is a very important concept because of heat transfer and the existence of temperature gradients.

In science, we learn about how all things strive to achieve equilibrium. Even in the absence of external forces acting on an object, the object will still strive to achieve equilibrium on its own. The movement always occurs from portions with higher concentrations to portions with lower concentrations to achieve equilibrium on all sides. This movement also applies to heat transfer.

In objects with varying temperatures or temperature changes, heat transfer will always occur due to the existence of temperature gradients. For instance, if you are heating one end of a steel bar to 200ºC and cooling the other end to 0ºC, heat will move from the heated end to the cooled to achieve an equilibrium temperature of 100ºC for the entire bar.

Now, what does all of this have to do with your home and temperature differential? A lot, actually. Because conditions inside and outside your home will always be different, a temperature gradient will always occur in the walls of your home. More extreme weather conditions will result in more extreme temperature adjustments within your home, which also results in a higher gradient in the walls.

Take this for example. A home typically maintains its inside temperature at 20ºC. More energy is used to maintain that temperature during winter when the outside temperature is at -5ºC, than in summer when the outside temperature is at 25ºC. That is because the temperature gradient is greater in winter than in summer, which results in a higher rate of heat transference.

So what does knowing all of this have to do with my house, you ask? An energy-efficient space translates to energy savings.

What Is Temperature Differential for Thermostat?

Understanding how temperature differentials work allows you to understand how large of a temperature gradient it creates and how much “pressure” is exerted on your system. This knowledge arms you with the ability to understand what temperatures to set based on outside temperatures so you have lower temperature differentials.

Why would you need this? Because you'll need to set your differential thermostat to lower settings while you're away or while you're sleeping to levels that are still acceptable to you but are less than the temperatures you are used to. This exerts a lower “pressure” on your HVAC system by creating less of a gradient while still remaining closer to acceptable levels. Not to mention, your electric bills will thank you when your air conditioners aren't set to super-low temperatures.

For instance, the average temperature in the US during the winter is 0ºC. In most households, the thermostat is typically maintained at 20-25ºC. When you set your thermostat to 20ºC instead of 25ºC when you sleep, the temperature differential decreases to 20 degrees instead of 25 degrees, exerting less “pressure” on the system to heat up your entire home. Setting a lower temperature and using a thicker comforter for an extra warm bed translates to less energy consumption as less heat is required by the system to maintain your ideal temperature.

This temperature difference can also be used on adjustable cycle rate differential thermostats wherein a temperature differential is set so the thermostat automatically adjusts the cooling equipment and heating equipment to get you back to the correct setting when it deviates without manually changing anything.

In this case, a higher temperature differential from the set temperature can lead to more savings than when the differential is lower. This is because an HVAC system has greater energy usage when the air conditioning unit or heating unit turns on. Increasing the interval between cycles of turning on and off also decreases your energy bills as it uses less power to heat up or cool down the area than to power up the unit.

Programmable Thermostat with Adjustable Temperature Differential

A programmable thermostat allows you to set the temperature to any setting you want. Some of these thermostats, like many Honeywell thermostats, for example, allow you to even set various desired temperature programs for various days of the week. If you anticipate the weather to be a little cooler on Wednesday and hotter on Friday, then you can set different air conditioning and heating system schedules and cycles on a programmable thermostat for both dates.

Other systems already have a built-in temperature differential setting of ±1 degree while others have a ±3 degree temperature differential. For most programmable thermostats, this built-in three or one-degree temperature differential is already set and cannot be changed.

But there is also an option for a programmable thermostat that allows you to adjust the temperature differential. This allows you to choose a heating and cooling system setting that's more comfortable for you. Remember that a higher temperature differential means high efficiency and savings but would also take more time to heat back up or cool back down. On the other hand, a lower differential will mean it takes less time to cool down or heat up, but would also mean less energy saved.

Before you purchase a programmable thermostat, be sure to check the manual for any indications if these differentials are changeable and if different schedules for the air conditioning and heater are an option.

Blackhawk Supply Thermostats

For all of your thermostat needs, Blackhawk Supply has you covered. From programmable thermostats to mechanical thermostats, there will always be something for you. Choose from a variety of high-quality thermostats from ACI, Braeburn, Veris, KMC, Viconics, Johnson Controls, or Honeywell thermostat options that are sure to be the perfect fit for your home or office's HVAC system.