What kind of maintenance does a gas furnace need?

The basic heating cycle for a forced-air furnace heats by way of the following process: 

1. The gas is ignited in the burner.
2. A metal heat exchanger is heated up by the heat of the flames and it exhausts out the flue.
3. The heat is transferred into the air through the exchanger.
4. The heated air is forced by the blower through the ductwork, distributing it through the home.
5. Cold air is denser than warm air, and because of that, it is drawn back in the furnace as the warm air fills the house.

There are several components that, in a gas furnace, work together to make your home comfortable and warm. Some of the components, their functions, and why gas furnace maintenance is important include:

• Thermostat: This is a temperature-activated switch. When the indoor temperature drops below the setting it tells the furnace to cut on. 
• Draft Hood and Fan: As the burners draw air in, the air mixes with the gas and becomes combustible. Today, there are high-efficiency models with a draft-induced fan that makes the combustion leaner and offers better gas furnace efficiency. The fan blows the heat from the burners into the heat exchanger. Exhaust gases are then vented outside.
• Burners: Furnace burners consist of tubes that gas goes through, and then a gas valve, the igniter, and a flame sensor to control the flames. As the heating system requires heat, the gas valves are opened, and the air/gas mixture is ignited. 
• Heat exchanger: There are metal tubes that the burners heat up, and as the gas becomes combustible inside the heat exchanger, metal baffles are heated and transfer the radiant heat to the passing air. If the heat exchanger is damaged in any way, that combustible gas will leak in the house, putting everyone at risk. This is one reason routine gas furnace maintenance and inspection are so important. 
• Blower: The blower motor directs air with a fan, taking the return ducts air into the heat exchanger and forcing the warmed air through the ductwork. 
• Flue: This is where the combustion gases are collected and sent outside, away from your home. They are typically made of galvanized steel. 

How long does a gas furnace usually last?

A quality gas furnace that is professionally installed and has the recommended and needed furnace maintenance performed may last up to 20 years, and perhaps even longer. If your gas furnace is reaching that 15 to 16-year mark, begin shopping around so that you’re better prepared when the time comes and you don’t find yourself making a panic decision with your purchase. 

How much does it cost to replace and install a furnace?

There are multitudes of brands on the market today when it comes to gas furnaces. You want to do some research before purchasing one, which is why you need to start shopping before you need one. Get one that is the right size for your home, and note that too small is just as bad as too large. A gas furnace installation can start around $3,500 and go as high as $10,000, depending on the area where you live and the brand and model of gas furnace you choose. 

If you’re trying to choose between a gas furnace vs heat pump, but not sure which is better for you, consider that here in California, natural gas is cheaper than electricity. With that in mind, operating a gas-powered furnace will cost less than a heat pump. However, the more energy-efficient an HVAC system is, regardless of how it is powered, the less power it will take no matter whether it is electric or gas. 

Will a gas furnace work without electricity? 

You’ve likely heard many say that they like having electricity and gas because they can still keep warm with their gas furnace even if there is a power outage. To clarify, while a gas furnace will need gas to heat your home, it will also need electricity for the blower motor and the igniter. Even if you can get it lit and started without the igniter, it won’t blow the heat out as it should. 

What does a gas furnace that smells like burning mean? 

There are three categories that a gas furnace maintenance call will usually fall under when the complaint is a burning smell:

• Dusty burning smell: This could be because the filter needs to be changed. Try that before you call for a professional gas furnace maintenance service. It can also come from the unit sitting up all summer with dirt and dust accumulating. 

• Rotten egg smell: That is the smell of sulfuric acid that is added to natural gas to give a warning there is a leak. As soon as you smell that, turn the system off, vacate your home, and call for emergency gas furnace maintenance.

• Burning metallic smell: If it isn’t dust burning off or leaking gas, a burning smell could be telling you there is an electrical or mechanical problem that needs immediate gas furnace maintenance service. 

What does a gas furnace blowing cold air mean?

If your gas furnace is giving you the cold shoulder, so to speak, there are several causes. Note that some of them you can fix yourself without needing professional gas maintenance service.

Check the Thermostat Setting

If the thermostat fan setting may be set to ON, the blower motor will run constantly no matter whether you need air conditioning or heat. You want to have it set at AUTO for the best results.

Check the Air Filter

Change the air filter. This should be done every 30 days at the very minimum. When the air filter is dirty, the airflow is blocked from the heat exchanger. This can cause the system to overheat and trip the switch that turns the burner off. After changing the filter, if it is still blowing cold, you’ll need to call for a professional gas furnace maintenance service. 

Check the Pilot Light

If your gas furnace has a pilot light, make sure it is lit. If it is off, then follow these steps: 

Step 1: Turn the furnace 

Step 2: Reset the pilot light assembly switch

Step 3: Turn the assembly knob to “off” and wait 5 minutes

Step 4: Turn the assembly knob to “pilot”, press down hold a lighter to the pilot until you see the flame light up

Step 8: Turn the assembly knob to “on”

Step 7: Turn the thermostat to heat and on

Check the Condensation Line

Check to see if there is water pooled up around the furnace. If so, check that the condensate line is clear and if blocked use can air to clear it.