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Virginia HVAC and Plumbing Companies for Hire Explain Systems Functions

In CategoryTim Whitcombe
ByGardenAdvice Tim Whitcombe


A HVAC unit is an essential device for your home because it heats and cools your home. When you install a first-rate HVAC unit, you can say goodbye to extreme summer and winter temperatures. 

Have you have ever wondered how the HVAC in your home works? Well, let the professionals at  https://www.dmselectservices.com/fairfax-station-va-hvac-repair explain. 


Types of Heating and Cooling Distribution Structures

Knowing how each type of distribution structure works, will give you a clearer understanding of how the one in your home works.

Forced Air – This mechanism uses a blower to push cold and hot air through metal ducts. The hot and cold breeze are pushed through different ducts but that is dependent on whether you’re using the air conditioner or furnace. 

These systems are prone to blowouts and as they malfunction or stop working as they get closer to their lifespan. There are volume issues with the cheaper ones. 

Gravity Systems – These function along with the “hot air rises and cold air sinks” theory. Therefore, gravity and air conditioning mechanisms cannot be used jointly. Gravity mechanisms are installed in basements. When turned on, the hot wind goes the ceiling, heats your home then falls when it cools. The cycle continues. 

Radiant Systems – These are similar to gravity systems in that you can’t use them along with air conditioning ones. Radiant heating heat rooms via heat devices such as radiators, which circulate heat throughout a room. The main disadvantage of using these is that the pipes used to carry hot water tend to breakdown because they deteriorate or there’s a buildup of mineral residues.  

HVAC System Parts and their function

Understanding how the different parts of your HVAC unit works is important. Although there are several models with special features, there are few differences between them. Each unit has four major parts.

  1. Furnace: The furnace contains a heat exchanger that burns oil or natural gas that heats the air to the correct temperature. The furnace is usually placed inside in the basement, attic or a closet space designed solely for it.  
  2. Air conditioner: This device is placed outside. Electricity and coolant liquid in the air conditioner lower the temperature
  3. Ductwork: This is the transport mechanism whereby both hot and cold air are carried to every section of your home.
  4. Thermostat: This is the core of the HVAC unit. It works like a switch to turn the unit on and turn it off. It also regulates the temperature and controls other special features you might have installed with your HVAC.   

The core of the HVAC System

The thermostat is the heart of your heating system. It is heat-sensitive. It controls the temperature in your home and responds automatically to the present temperature.

When you establish the set point, the temperature is set manually and the thermostat will respond by turning off the furnace if the temperature does not correspond with the set point. The bimetallic element is the key component that either contracts or expands when there is a change in the temperature inside your home.

Older thermostats models have two visible contacts. The bimetallic element bends as the room cools and contact electronically before the second contact is made. The second contact results in activating the system, and this starts the heating mechanism.  For more info check this URL: https://en.wikipedia.org/wiki/Heating,_ventilation,_and_air_conditioning

Modern thermostats

Modern thermostats don’t function like the older ones since the contacts are closed to the elements. They are protected behind glass.  As the temperature falls, the contacts straighten. A steel bar and a set of magnets close the contacts to complete the electrical circuit whenever the temperature gets too low.

It works directly in the opposite way when you have to turn off the furnace.

Modern thermostats are more accurate than the older models. They also last longer because the electrical contacts are protected behind glass.


A HVAC system is not a complicated device. Basically, it is a furnace and an air conditioning system. The thermostat controls the way your unit works.

If you are planning to install a new HVAC unit in your home, you need to do a thorough research. Select several companies and ask for quotes and get a professional to come and do an inspection of your home. The costs will be dependent on the type of house you have and its layout.  







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