Everything You Need To Know About Furnaces

How A Furnace Works


When it comes to winter seasons, your day-to-day comfort depends on the performance and quality of your furnace system. Furnaces are an essential part of the home that needs regular maintenance and upgrades to sustain the longevity of your system. Whether you’re replacing a furnace, wondering how to maintain a furnace, or just simply curious about how a heating system works—this is your ultimate guide. Let’s take a look at everything you need to know about furnaces.

First things first, how does a furnace operate?

Simply explained, a furnace begins with the thermostat. Whatever desired temperature you set for your home, the thermostat will then detect when that temperature has dropped. From there, the thermostat signals the furnace to activate. The furnace will run until the temperature has reached the set comfort level.

There are different variants of furnaces, however, most homeowners commonly use either electricity or natural gas to warm the air.

For a gas furnace, when a thermostat triggers the furnace to turn on, a valve will open and supply fuel to the pilot light. The pilot light ignites, lighting the burners in the combustion chamber. This heats up the heat exchanger.

Perhaps the most critical part of your furnace, the heat exchanger gets hotter and hotter. Once the air is heated up sufficiently, the air is moved into the plenum and exits through the supply ducts. From there, the air heats the home to the set temperature.

Working parts of the gas furnace include the burner, heat exchanger, ductwork, ventilation pipes or flue, return ducts, air filter, blower motor, supply plenum, and hot surface ignitor.

For an electric furnace, the air is drawn into the furnace system and through a heat exchanger. From there, heating elements heat the air; the blower pushes the air into your home’s ductwork. The ductwork will then distribute air evenly throughout the areas of your home.

Working parts of the electric furnace include electric heating elements, air filter control, cold air return, air filter, blower, belt, motor, and ductwork.

Furnace Maintenance: 4 Simple Ways To Maintain Your Furnace System

The longevity and performance of your furnace largely depend on regular maintenance. We can not stress enough the importance of keeping your system maintained. This prevents spiked utility bills and detrimental damages that’ll lead to replacing your furnace system long before the end of its lifespan.

Generally speaking, we recommend you schedule routine maintenance with an HVAC professional to get thorough inspections on your system. However, if you’re looking for simple things you can do on your own, here are four ways to maintain your system easily between your annual furnace maintenance.

Replace Or Clean Air Filter

Whichever your system requires to run properly, cleaning or replacing the air filters to your furnace is a simple sure way to maintain your system. Although it may seem like a minor component of your unit, air filters serve the critical job of delivering warm air throughout your home.

Furnace filters are usually located where the return duct enters your furnace. Here, these filters work to remove contaminants from your air: bacteria, dust mites, pollen, pet dander, spores, particles, and many more. When air filters become dirty over time, this will block airflow causing your home to not heat effectively—which means your system is straining to heat the home.

For standard air filters, we recommend changing your air filters anywhere from 30 to 90 days. For more expensive disposable air filters, you may only need to change your system every three to six months. Take a look at your manufacturer’s recommendations or contact a certified technician to find out what’s best for your system.

Ensure All Household Vents Are Free

This is another simple but crucial component of maintaining your system. Please remove furniture, boxes, and any other household items that may block household vents.

To warm your home, air must circulate throughout your system to work properly. If household items are blocking your air vents, this impedes airflow, causing your system to overwork itself.

Inspect And Lubricate The Blower Motor

When maintaining your system, inspect and lubricate the blower motor. The blower is powered by an electric motor in order to propel heated air through the ductwork and into your home.

To prevent excess friction between the oil and the bushing of the blower motor, it’s important to ensure that the blower is frequently lubricated.

In addition, inspect the blower belt for wear and tear. If the belt appears loose, tighten it by sliding the motor back. If the belt appears frayed, tethered, or damaged, contact an HVAC professional right away to get a blower motor replacement.

Check The Flue Pipe For Leaks

Inspect the flue pipe coming out the top of the furnace to make sure it’s venting properly. If you discover any holes in the flue pipe, patch small holes temporarily with foil tape and contact an HVAC professional right away. A flue pipe leak can release dangerous chemicals such as carbon monoxide, nitrogen dioxide, and sulfur dioxide.

A flue pipe can threaten the safety and wellbeing of you and your family. If you do have a flue pipe leak, your family may experience the following:

  • Headaches
  • Nausea
  • Dizziness
  • Collapse
  • Fatigue
  • Heart palpitations
  • Unconsciousness

Flue pipe leakage is dangerous and should be repaired immediately. If you suspect that you’re experiencing this, speak with an HVAC technician as soon as possible.

What Is The Cost Of A Furnace?

So what’s the price tag on your furnace system, you wonder? The cost of your furnace can depend on many variables such as local climate, location, unit type, size of home, the brand of the unit, the quality of the install—the list goes on. For instance, your furnace installation may increase if your home needs extensive electrical or ductwork.

Also, depending on where you live, certain towns may need a permit for a furnace installation. This can vary in price from as little as $50 to hundreds of dollars. Please also keep in mind that an expectation may need to be completed by the municipality or city. It’s always best to check on your local bylaws.

As a general rule of thumb, when purchasing a furnace, the cheapest option isn’t always the best. We know—cheaper furnaces are rather tempting. However, your furnace has a significant duty to maintain your family’s comfort within the home. Purchase a furnace worthwhile that’ll not only keep you comfortable but save you money in the long run on repairs, maintenance, and so forth.

This refers to the furnace installer as well. It’s super important that your furnace is installed properly to ensure the safety of your loved ones and maintain your system’s performance. You’ll want a certified technician that not only installs your furnace to the highest standard but also can maintain it for years to come.

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The Different Types Of Furnaces

As discussed at the beginning of the article, there are a variety of furnace types: primarily natural gas and electric furnaces, but oil is another heating selection. Along with your furnace type, you also have to consider whether you want a forced-air or radiant heating system. This manages how your heating system distributes heat throughout your home.

A common heating method, the forced air system pushes air through the ducts and vents that connect to a unit. Considered this a closed loop formula: heating is constantly being pulled and pushed from your home.

On the other hand, radiant heat systems may have several variants and will rely on boilers to send heater water through a series of pipes to radiators. Wherever the radiators or baseboard are installed is where they’ll provide heat. Radiant heating systems may also exchange heat to a floor through installed hot water tubing beneath the flooring surface!

For this article, however, we’ll discuss the different variants of forced air furnaces since this is the most popular choice out of the two. Forced air furnaces are also more eco-friendly. Let’s take a look at the three most common heating systems: gas, electricity, and oil.


As the most popular furnace type, gas furnaces are the best solution for areas with harsher winter weather. Although gas furnaces have a higher initial cost than electric units, this cost equals out by having a lower monthly operating cost.

In addition, gas furnaces are more efficient and heat the home faster. Contrary to electric furnaces, a gas furnace will need additional maintenance, installation, and replacement costs. For instance, a gas system will need annual inspections, replacement filters, and ductwork cleaned regularly to perform to its best standard. A gas furnace’s general lifespan is around 15 years.


For those who don’t experience brutal winters, electric furnaces are the perfect solution. When compared to the gas furnace, the electric furnace will have the lowest upfront cost. However, due to the cost of electricity, this system will be more expensive to operate on a monthly basis.

Along with a cheap initial cost comes the perks of low maintenance, meaning, it’ll be cheaper to maintain an electric system. Electric systems are fairly energy efficient and don’t require a lot of moving parts to operate, hence, the low maintenance cost. Generally, temperatures above freezing are good for these furnace types. Due to its relatively small size, furnace installations are mostly easy and won’t require special piping or venting. The average lifespan of an electric furnace is 15-20 years.


Last, and quite frankly least, you have the oil furnace. Oil furnaces aren’t typically sought after due to its high fluctuating oil prices. On the bright side, oil furnaces are good choices for those who experience intense winter weather. Oil furnaces will require a storage tank, along with spacious accommodations, so you’ll have to consider additional install costs for this one.

With an oil furnace, there’s no monthly cost. You instead only pay oil when your storage tank needs refilling. Depending on the tank, this purchase will occur quarterly, semi-annually, or maybe even annually if you have a high-quality storage tank.

Keep Your Home In Quality Condition

With over 60 years in the industry, Air-Rite Heating & Cooling can maintain the quality of your home with our expert furnace repair, furnace installation, and in-depth knowledge regarding heating systems. Our team of certified experts will gladly answer any questions or concerns you may have about your system. For any heating and cooling repairs, installations, and maintenance, contact us today!

We provide the finest in HVAC installation, maintenance, and repair across The Greater Chicago land area including Burr Ridge, Wheaton, Huntley, Aurora, Vernon Hills, Naperville, and more.

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