Guide to the Different Types of Thermostats for Homes

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Submitted by Mohammad A on Saturday, February 16, 2019.
Guide to the Different Types of Thermostats for Homes

Home Thermostat Basics

A thermostat regulates your home temperature, humidity and can benefit you in controlling energy conservation. So, your optimal choice of a thermostat hinges on the type of heating and cooling system you have in your house, and how you would like to use its basic and additional features.

Contents

1) Identifying the Correct Thermostat Type

Before choosing the correct thermostat, as a house owner you need to make sure your thermostat is attuned with your heating and cooling system. The most common system categories related to central heat and air are ones powered by electric, gas or oil. Other, house-hold thermostats include floor/ wall furnace, fireplace, electric baseboard, and heat pump.

1.1) Remote Energy Thermostat (RET)

This kind of thermostat allows you to program, and monitor your heating and cooling arrangement directly from your tablet, smartphone and a laptop. This thermostat allows you to connect via a hub to your home broadband network, countenancing you to access it over Wi-Fi from anywhere (sitting in any location).

1.2) Digital Non-Programmable & Programmable Thermostat

A non-programmable thermostat with a digital read-out is the optimal choice for you people who might select manually controlled settings with the accessibility of easy-to-read LCD display. A programmable thermostat is an effective system through which we can automatically regulate the set temperature throughout the whole day, monthly or year. With this system, you can set your preferred temperature for different times of the day or night and let the thermostat control system to control it by itself.

1.3) Smart Thermostat

A smart thermostat, occasionally called a connected thermostat, is mainly used in homes. It can either be connected / hooked up to your internet connection and can be accessed/ controlled through an application which can be downloaded from the vendor’s website. This type of thermostat can also calculate the temperature and humidity and you can also adjust the air conditioner temperature accordingly such that you can have optimum relaxation in your house.
These thermostats can work similar to programmable thermostats as you can program them to turn your temperature up/ down depending on your presence in your home. As you are aware that such thermostats are typically more expensive due to their complexity as you can control it from anywhere even when away from home.

1.4) Wi-Fi/ Bluetooth Thermostat

With the breakthroughs and advancements in the field of wireless technology, devices are getting wire-free, portable and smarter. These devices are now connected with the wireless protocols like Bluetooth and Wi-Fi with the more common type being Wi-Fi. The wireless connection is usually for your phone, pad or computer to connect to the thermostat rather than the thermostat itself wirelessly connecting to your HVAC appliances.

1.5) Touchscreen Thermostat

These are typically hard-wired to your HVAC system and provide a display with a touch screen for programming your thermostat. They usually have all the features of a programmable thermostat.

1.6) Manual/ Outlet Thermostat

A manual thermostat is also called as mechanical thermostat. It is a type of Line-voltage thermostat which are easy to mount or set-up. It operates by triggering through the metal bar which is cool-down or heat-up. They are in fact the easiest and cheapest thermostat available in market. Somehow, these thermostats are regarded as unreliable and its bi-metallic strips response might cause variations in the temperature, below or above the preferred set-point.
Note that these are an older type that often contain mercury which is a toxic metal and many states have regulations about the proper disposal of old ones- see this article for further information.

2) HVAC Thermostats

While all the types of thermostats above can be used for controlling individual heating or cooling appliances, HVAC (Heating, Ventilation and Air Conditioning) thermostats are designed to control all systems simultaneously and can take the form of the types referred to above.

One most important things they have in common, is that practically all such kind of thermostat are low-voltage and power-driven by a transformer which is coupled to the air conditioner/ furnace through series of low-voltage cables.

So the question is when to choose between a programmable or non-programmable thermostat for your HVAC system.

A non-programmable thermostat has the capacity to control the room temperature to only one-desired point, and its setting can manually be changed if you require a new set-point. Whereas, for programmable thermostats can be set to change temperatures at specific times of the day, week or month.

Programmable Vs Non-Programmable HVAC Thermostats
HVAC Thermostat Specification Programmable Thermostat Non-Programmable Thermostat
Mechanical Thermostat This type has a mechanical timer and few switches having a manual user setting which offers basic functions for programmable thermostats. It usually uses a mercury switch in order to complete the circuit. These thermostat uses primarily mercury bulb that uses mercury in order to make contacts/ energize the cooling/ heating. Some mechanical thermostats do not have mercury and uses a regulated magnetic/ Bi-metallic strip.
Digital Thermostat This kind of thermostat offers multiple functions, settings for a whole range and combination of HVAC equipment. Most programmable thermostats are very easy to program. They are typically solid-state which uses temperature sensing device called as thermistor. These thermostats are relatively easy to hook-up, however if you have trouble understanding the instructions then it's best to get a technician who understands HVAC control wiring.
Data-logging This kind of thermostat records the temperature over Intervals in order to maintain a record of the temperature. They're often used by professionals to troubleshoot issues over a period of time to find irregularities in a certain area. They are also used by modern building management systems to control the temperature all over the rooms to make discover if unwanted temperatures are taking place. It can be either mechanical or digital. Note that some smart thermostats provide this functionality by storing this information in the cloud.

3) Types of Thermostat

Some kinds of thermostats work with all heating and cooling systems, but some have special requirements and only work with specific systems.

3.1) Bulb Thermostat

Bulb ThermostatThese have a single/ double-stage, heating or cooling temperature controller which uses a liquid-filled sensing element and also has a capillary. It contains concealed set point-deals with regulating differential and it will switch line voltages. This unit uses 120 VAC or 240 VAC to operate. These are less common that the other types for home use.

3.2) Fan Coil / Proportional Thermostat

Honeywell Fan Coil Thermostat
Fan-coil/ proportional thermostats can work with 24v DC, 120v and 240v AC systems. They are designed for Building Automation systems and used in residential buildings. It can be used in both manual/ automatic modes in order to change the remote thermistor temperature sensor. They typically have the following features:
  • Fan & system switching models
  • Remote sensor capability
  • Control multiple fans

3.3) Heat-Pump Thermostat

Honeywell Heat Pump Thermostat
These usually have a digital or multistage 7-day programmable/ non-programmable Proportional-Integral thermostat. These can be used to control a heat-pump for both cooling/ heating applications. Different brands have diverse function like fan switching with Internal or remote sensor capabilities. They tend to have a simple menu with around 10-20 configurable parameters to play with. Other features include:
  • Three status LEDs (fan, heating & cooling)
  • System switching (Off/ auto/ cooling/ heating)
  • LCD display
  • Cycles per hour for cooling/ heating
  • Fahrenheit/ Celsius Operation
  • Engaging the set-points
  • Supply voltage 20 to 25 VAC.

Note that many regular thermostats cannot be used with a Heat-Pump system.

3.4) Line-Voltage Thermostat

Line-Voltage ThermostatThese are installed in series with heaters and it mostly run on 120v or 240v AC mains power. They work in a way that current flows through the thermostat and into the heater. They use thick wires (2 or 4 wire) which is coming out from its back. As well as being used with regular systems, they are also used with electric heaters that draw large amount of current and voltage.

3.5) Low-Voltage Thermostat

Emerson Low-Voltage Thermostat
This is the most common type of thermostat used with home HVAC systems, furnaces, boilers, air-conditioners, and humidifiers. They run off of voltage around 6-30v. They come in a variety of types like electronic programmable, digital and bimetallic. The low voltage means they only need thin wires like 18 AWG in order to operate.

3.6) Low / High Limit Thermostat

Low / High Limit ThermostatThese incorporate a vapor charged sensing element. They are designed in order to transfer a set-point such that when the main contact opens, auxiliary contact closes instantaneously. Important applications of Low/ high limit thermostats include shutdown of a ventilation system, and Building Automation Systems that indicate low/ high temperature. They're not typically used in home systems.

4) Pros and Cons of Smart Thermostats

Pros and Cons of Smart Thermostats

A Smart thermostat helps in reducing the overall energy usage through controlling home’s temperature at any Interval. Although we have many positive things related to a thermostat but these items also have some drawbacks as well. In the following table we will give some Pros and Cons in deciding whether to go for Smart thermostat or not.

Pros Cons
Adjusting and controlling the temperature in your home at any time from any location. Opens up the possibility of hackers gaining access to your system.
Many smart thermostats learn from your behavior and adjust accordingly. If in the morning you are going for work each day, it will identify your habit and will reduce energy usage while you're out and start cooling or heating prior to you arriving home. Smart Thermostats tend to be more costly, so you may be able to get all the scheduling you need from a simpler programmable option.
They usually allow you to monitor your energy usage in real-time. This allows you to better manage your energy consumption and can help you to save money on your energy bills. Due to the added upfront cost, it will take time before you realize a net saving.
Smart thermostats can signal when it’s time to change the filter for your air-conditioner or furnace. You can also do this simply by setting a reminder to change your filters according to the manufacturer's recommendations without the added cost.

Conclusion

These days in market we have wide variety of brands to pick from, all you need is to consider your budget, your schedule and temperature preferences. Most people opt for a smart thermostat or programmable one with a digital display.

You might also like to read:
• Guide to Understanding the Different Types of Garage Heaters
• 5 Practical Ways to Save on your Energy Bills
• A Look at the History of Modern Air Conditioning
• The Pros and Cons of Technology's March into our Homes

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