How to Clean a Furnace: 4 Steps to Take Before Winter

how to clean a furnace

Don’t Wait Until the Cold Outside Gets Inside

When it comes to proper and effective furnace cleaning and maintenance, the old adage of “prevention is the best medicine” is key. Your furnace can’t function efficiently without proper and timely maintenance. If you don’t clean your furnace as part of regular maintenance, you can expect to suffer any number of problems, the worst of which is not getting heat when it’s cold outside.

Which is why the best time to clean a furnace is before winter arrives. That way you head off the possibility of a furnace failure that could leave you and your family shivering in the dead of a winter night. Not to mention suffering a hefty bill from your HVAC contractor to provide emergency furnace repair service.

There are additional benefits to cleaning your furnace before the winter heating season. Proper furnace maintenance also helps prolong the service life of your system, increasing your return on investment. Equally important is that an efficiently running furnace helps keep your energy bills as low as possible.

Here is our step-by-step guide to properly cleaning a furnace and preparing for winter:

Step 1: Turn the Power and Fuel Supply Off  

First and foremost, before you do anything else, turn off the electrical power and fuel supply to the furnace. Locate the off-on switch for the electric power and turn it to the off position. Locate the fuel shutoff valve; for an oil furnace the valve is typically near the oil tank, and for a gas furnace the valve is usually on the incoming gas pipe.

Do not, for any reason, skip this step. Your personal safety and the safety of your family depends on it. 

Step 2: Clean the Combustion Chamber and Blower Compartment

Remove the door to the combustion chamber and vacuum it. Inspect for any corrosion or holes. Lift the door to the blower compartment and vacuum. Again, inspect for any holes, then replace the door.

Pro tip: While you are doing this, it’s also a good idea to inspect the ductwork connected to the furnace for any holes or gaps, and patch accordingly. Leaks in the ductwork impair furnace efficiency and performance. In fact, leaks in ductwork throughout your house can cause a great deal of heat loss, as much as 30 percent. Your furnace is forced to work extra hard to make up for this heat loss, using more energy than under better sealed conditions. Sealing leaky ducts is one of the most beneficial furnace maintenance tips for energy savings. 

Step 3: Clean the Furnace Filter

The purpose of a furnace filter is to trap dust, dirt, and other airborne particles so they don’t get into the furnace itself and potentially damage internal components. Which means it gets dirty. A dirty furnace filter makes the furnace work harder, impairing efficiency.

While cleaning and/or replacing the filter is an important part of pre-winter maintenance, it should be performed more frequently than just then. In fact, you need to change fiberglass and paper filter furnace filters every one to two months; electrostatic and HEPA (High Efficiency Particulate Air) filters need to be changed or cleaned every two to four months. If you have pets and/or family members who use tobacco products, the frequency of necessary filter changes increases.

Cleaning or replacing your filters is the best and easiest way not only to maximize furnace efficiency, but also to keep your indoor air as clean and fresh as possible.

STEP 4: Oil the Furnace Motor Bearings

If you have an older furnace, more than likely there are two motor bearings and two blower-shaft bearings. Oil these bearings at least once a year; before winter heating season is a good time to do this. Start by using a clean cloth to wipe the caps over the bearings. Then remove the caps and apply two or three drops of lightweight machine oil to each bearing. Don’t overdo it; overlubricating can actually lead to overheating and potentially damage the bearings.  When you’re finished oiling, restore the caps to their original positions.

Depend on the Furnace Maintenance Experts—Ongaro and Sons 

Even if you are confident that you can change air filters, vacuum furnace compartments, remove debris near the furnace, and oil motor bearings on your own, it’s still a good idea to have a certified HVAC specialist perform regular maintenance on your system. There are certain things only a trained technician knows how to do. These include: 

  • Testing the furnace to ensure it is receiving sufficient power. If the unit doesn’t have sufficient energy to transfer heat from the coils, it makes it more difficult to efficiently reach and maintain desired temperatures throughout the house.
  • Replacing damaged coils. Coils also collect dirt and debris. If they’ve been cleaned regularly, they should last. However, if the coils are for any reason damaged, they need replacement.
  • Checking thermostat heat. Thermostats do wear down over time and malfunctions may stop proper furnace functioning. Checking that thermostats are operating properly ensures furnace efficiency, as does replacing them as needed.
  • Checking fans. To the untrained eye, furnace fans may very well look as if they are functioning. However, only a trained HVAC professional knows what to inspect for and how to ensure efficient fan operation.
  • Repairing/replacing ductwork. Patching gaps in the ductwork leading to the furnace stops leaks. However, if you see gaps in the ductwork, patching it is only a partial remedy. More than likely dust and debris got into the ductwork, which is circulating into your house and impairing furnace performance. Cleaning out ductwork is not a job for your home vacuum cleaner. Your HVAC contractor uses a special high-powered vacuum designed especially for this purpose.

It’s also a good idea to consult with a knowledgeable HVAC expert if you are considering changing or upgrading the air filtration system connected to your furnace. An experienced HVAC technician can help you weigh the pros and cons of different air filtration systems to determine the application that best fits your home and family’s needs.

As we’ve outlined in this guide, most homeowners are capable of performing some basic cleaning of their furnace before winter heating season. However, a regular maintenance plan performed by an experienced and reliable HVAC company best ensures optimum performance. Call the heating and cooling specialists at Ongaro and Sons.