March 1, 2019

HVAC System in St. Louis, MO

What Is Included In Your HVAC System?

HVAC is one of those terms you’ve probably come across if you’ve ever searched for heating and cooling services online. But what exactly do you get with an HVAC system? For starters, HVAC stands for heating, ventilation and air conditioning, which is basically everything you need to stay comfortable throughout the year. Keep reading to discover what’s specifically included with a typical HVAC system.

A Heating Source

If you live in St. Louis or any of the surrounding areas, you’re probably aware that the late autumn and winter days and nights can get cold. This is when you’ll be glad that you have the right heating source for your needs and budget. Heat is often provided by a furnace, boiler or heat pump.

The most common is the forced-air furnace, with gas, oil, propane, and electric models available. Within these units are the burn chamber for fuel-burning models, the heat exchanger, and the circulating fan.

Furnaces typically have a circulating fan built into the unit, which takes the place of an air handler. The job of an air handler is to draw air through the system and push it back out into your home. If you have a heat pump, you’ll need one, which will likely also house your inside coil.

Growing in popularity is the heat pump, which uses refrigerant to pull heat from the air outside and bring it inside. These pumps have similar components to air conditioners, with one key addition: the reversing valve. It’s this valve that allows the heat pump to both cool and heat your home.

Less popular in modern residential buildings is the boiler system. This has a boiler burner, boiler tank, and radiators in each room.

Air Conditioning

Air conditioning refers to any type of cooling system or unit that removes warmer air from your home while also generating and circulating cooler air. What an HVAC system does is allow you to combine the air conditioning operations with the heating functions all in one convenient system. Heat pumps are a bit unique in that they can keep your home both cool and warm. If set up correctly, a heat up pump can function without the need for a backup system.

Air conditioners and heat pumps are very similar in nature. These systems use refrigerant to absorb heat and transfer it someplace else. As for air conditioners, the refrigerant absorbs the heat from inside to transfer it outside.

To transfer the heat to and from the air, it has two coils, the evaporator coil inside and the condensing coil outside. The refrigerant works by the system adjusting the pressure up and down, which is controlled by the compressor and evaporator valve. The system also has a condensing fan, which draws air through the condensing coil outside.

Ventilation and Filtration

A common forced air system works by literally forcing heated or cooled air through a series of ducts and vents with fans and blowers. This type of ductwork is collectively referred to as ventilation. Many modern HVAC systems also include air filtration and cleaning elements. The purpose of these components is to improve your indoor air quality.


A critical component to your system is the air filter, which may be in your cool air return vent, in your unit, or in the ductwork near your unit. The purpose of the filter is to remove airborne contaminants before they can clog the internal components of your system.

Of all the components of your system, the air filter requires the most attention. Depending on your air quality and the size of your air filter, you may need to change this monthly, or it may last several months. Check with your owner’s manual for the recommended replacement schedule, but plan to check it every month. You can get a boost in your system’s efficiency by vacuuming off the filter between changes when you check it.

Be careful to only use the size and kind of filter intended for your system. Putting the wrong size of filter in may cause air to leak through that isn’t properly filtered. Using a specialty filter, like a HEPA filter, may choke your system, preventing enough air from flowing through.

Ducts and Vents

Standard systems won’t work properly without the ducts and vents. The ducts transport the conditioned air out to your rooms.

It’s important to seal and insulate these ducts to maintain your system’s efficiency. Leaks in your ducts prevent the right volume of conditioned air from reaching its destination. Likewise, if those ducts run through unconditioned rooms, they can work to transfer heat to and from the conditioned air. Both of these reduce your system’s efficiency, increasing your utility bills and the number of repairs.

Your vents are the key to not only bringing conditioned air into your rooms but also circulating it around your home. Your system creates low pressure at the cool air return vent while creating high pressure at your supply vents. This pressure difference creates circulation in your home, which helps it heat or cool evenly.

Blocked or closed vents inhibit circulation, causing some areas to be hotter and cooler than others. Make sure each of your supply vents has at least 2 inches clear around and above it to allow the air to circulate. Your cool air return may need more, depending on its size, so double-check with your HVAC technician or with your owner’s manual.


You may not naturally consider your thermostat to be part of your HVAC system, but it is the brain that makes everything work properly. Beyond that, it’s also the key to getting the best efficiency from your system throughout the year.

The thermostat senses the temperature in your home and signals for your system to turn on and off. It can also control the circulating fan, allowing it to move air throughout your home even when the system isn’t cycling.

There are a variety of thermostats available, with the most common being digital programmable and smart models. It’s the programming capability that makes your system function at its peak efficiency.

There’s no need to heat and cool your home to the same degree all daylong when there’s no one there to enjoy it. The Department of Energy recommends rolling back your temperature by 7 to 10 degrees during these periods to reduce the strain on your system. They’ve found that doing this for about eight hours each day may save you up to about 10% off your annual heating and cooling utilities.

A smart thermostat helps make managing those programs and your entire system easier. Smart-learning models learn when you’re home versus when you’re not based on when you adjust the temperature. It then creates a program for you that automatically runs. Remote-access smart thermostats allow you to control your home’s HVAC system from your smartphone, even when you’re away.

Exhaust Outlets

Part of the circulation necessary for your furnace to run properly is the exhaust outlet, or flue. This allows the gases produced by burning fuel to escape safely into the air outside, rather than leaking out into your home.

However, if this becomes clogged or blocked, which happens thanks to animals or malfunctioning dampeners, it will cause your system to shut down. In severe cases, it may cause your system to overheat, damaging sensitive components.

The exhaust outlet for most fuel-burning furnaces is through the roof of your home. If your furnace is near a fireplace, it may actually run up through the chimney. A high-efficiency furnace has cooler exhaust that isn’t as likely to cause damage, so it usually vents out through the side of the house.

Optional Components

There are several optional components that you may want to consider adding to your HVAC system as well. These additional components either help manage your air quality or help boost your system’s efficiency. Options you may want to consider include a system-wide humidifier, a dehumidifier, an air scrubber, a UV light purifier, and an energy recovery ventilator.

For more than 40 years, when people around St. Louis need HVAC service, they turn to Scott-Lee Heating Company. Heating and air conditioning repairs, installation, and maintenance and indoor air quality are what make our team shine. Call to schedule your HVAC service with one of our NATE-certified technicians today.