When the holiday decorations start to come out of storage and the temperature outside drops, the air conditioner switches off for the last time. Soon, you’re switching over to the furnace and enjoying the instant comfort created by having warm air flowing out from the vents around your home. When you dial your thermostat to your preferred heat setting and listen to the equipment turn on, you might find yourself wondering, “what is a furnace, anyway?”
Because of their ubiquity in homes across the nation, forced air furnaces and their newer cousin, the condensing furnace, are often taken for granted and overlooked. However, they are fascinating pieces of technology that today can capture well over 90 to 95% of the heat energy contained within a given fuel. Let’s look at how this hardware works and some of the most important things to know.
What is a Furnace? The Basic Ideas of Operation
Today’s furnace is a descendant of the traditional fireplace — a method of burning fuel to heat the home. Today, most modern furnaces are highly enclosed units that rely on either propane fuel or, more commonly, natural gas. The furnace’s job is to take that fuel, burn it efficiently, and use the heat created from that combustion to warm the air throughout your home — all while ensuring that the harmful combustion byproducts escape into the atmosphere outside your home.
The Parts of the Furnace To Know
The idea is simple enough, but there is a surprising amount of complexity in modern furnace units. Luckily, we can break it down into the individual parts that work together to heat your home. Let’s look at each of the critical stages of heating and how they work.
- First, your thermostat commands the furnace to turn on and provide heat. The system inside the furnace releases fuel from the gas lines feeding the furnace, which ignite inside several burners.
- These flames feed into a long series of metal tubes where additional fuel combustion takes place. These tubes, called the heat exchanger, become extremely hot due to the burning fuel and hot combustion gases inside of them.
- A blower motor forces air across the heat exchanger, cooling the tubes while heating the air simultaneously. This “forced air” then travels through your home, exiting from registers and heating rooms.
- What is a furnace with condensing technology? In condensing furnaces, exhaust gases go through a secondary heat exchanger that air also passes over as before. Water vapor from burned natural gas condenses on this exchanger and releases additional heat, driving up unit efficiency.
To recap, the furnace uses burners to combust fuel, which warms the heat exchanger, which transfers its heat to the air that reaches your home.
Can Furnaces Be Dangerous To Use?
Modern furnaces feature extremely safe designs that make them more reliable. Many even have built-in fail-safes to detect potentially unsafe operating conditions and lock themselves down to prevent danger. However, it’s important to remember that burning any kind of fuel produces carbon monoxide — a toxic gas that can be fatal with heavy exposure. Carbon monoxide can leak from poorly maintained furnaces and cracked heat exchangers instead of escaping to the outside air. For these reasons, you should always invest in both a personal carbon monoxide detector and routine maintenance.
Using a Furnace Effectively
Modern furnaces feature designs that make them highly efficient, so you can enjoy lower energy costs for the same level of comfort and heating that you typically expect. However, there are still steps you can take to ensure that you get the best value for your money from month to month — especially if you still have an older and less efficient unit. Try these tips:
- Consider investing in a programmable or “smart” thermostat. Create a program that heats your home only during the specific hours you need warmth. Don’t heat an empty home.
- Keep your filter clean and change it regularly. Good airflow is essential for effective heating, so don’t let your filter become clogged with dust.
- Seal your home and minimize air leaks. Don’t let that warm air created by your furnace leak out through drafty windows.
- Use a humidifier to maintain a level of humidity that helps you feel warmer and more comfortable. You don’t need to turn your home into a sauna, but a humidity level between 35-40% will make your space feel better.
- Invest in routine maintenance regularly. Having your furnace checked for a tune-up before the start of the heating season provides both peace of mind and the chance to correct any potential issues before they become failure points.
If you wondered “what is a furnace?” we hope this quick overview provided the answers you sought. Remember to contact a licensed and insured HVAC professional if you experience issues with your furnace and never attempt to service the unit independently.
FAQ Section: Understanding Your Furnace and How to Use It Efficiently
1. What is a furnace and how does it work?
A furnace is a home heating system that burns fuel, typically natural gas or propane, to generate heat. This heat warms the air, which is distributed throughout the house by a blower motor via ducts and vents. Modern furnaces can capture over 90% of the heat energy in the fuel, making them highly efficient.
2. How does a condensing furnace differ from a traditional furnace?
Condensing furnaces have an additional heat exchanger that captures more heat from exhaust gases, boosting efficiency to 95% or more. The secondary exchanger condenses water vapor from combustion gases, releasing extra heat that’s used to warm your home, lowering fuel consumption.
3. What are the main components of a furnace?
Key components include the thermostat, burners, heat exchanger, and blower motor. The thermostat signals the furnace to ignite burners, which heat the exchanger. The blower then pushes air over the exchanger, heating the air that flows into your home.
4. Can furnaces be dangerous?
While modern furnaces have built-in safety features, they can still pose risks. Carbon monoxide, a byproduct of fuel combustion, can leak from damaged furnaces. It’s essential to have regular maintenance and install carbon monoxide detectors to prevent exposure to this toxic gas.
5. How can I improve my furnace’s efficiency?
You can increase efficiency by using a programmable thermostat, sealing air leaks, maintaining a clean air filter, and regularly scheduling furnace tune-ups. By improving airflow and reducing heat loss, your furnace can run more efficiently and cut energy costs.
6. How often should I change my furnace filter?
Filters should be checked monthly and replaced every 1-3 months, depending on the type of filter and your home’s conditions. A clogged filter restricts airflow, making your furnace work harder and reducing efficiency.
7. Is routine furnace maintenance necessary?
Yes, regular furnace maintenance ensures optimal performance and safety. Schedule a yearly tune-up before winter to check for leaks, cracks, or other potential problems. Preventative maintenance extends the furnace’s lifespan and helps avoid costly repairs.
8. What is the ideal thermostat setting in winter for comfort and energy savings?
The U.S. Department of Energy recommends keeping your thermostat at 68°F while you’re home and awake and lowering it by 7-10°F while you’re asleep or away to save on heating bills. Using a programmable or smart thermostat can automate this process.
9. What is a heat exchanger, and why is it important?
A heat exchanger is a crucial part of a furnace that transfers heat from the combustion gases to the air blown through your home. If a heat exchanger cracks, it can leak carbon monoxide, so regular inspection is essential for safety.
10. Can a humidifier improve furnace performance?
Yes, maintaining humidity levels of 35-40% can make your home feel warmer without raising the thermostat. Humid air retains heat better, helping you stay comfortable while using less energy, thus reducing heating costs.
