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Everything You Need to Know About High Efficiency Furnaces

Mother & daughter making paper snowflakes by the window inside a warm home

If you’re in the market for a new furnace, you may be wondering if a high efficiency model is the right choice for your home and family. The Department of Energy reports that heating your home is about 29 percent of your energy bill which is a big deal for homeowners looking to keep costs down. Efficiency is a key factor in saving money and staying comfortable.

In this guide, we will review all you need to know about high efficiency furnaces to make an informed decision.

What is a High Efficiency Furnace?

A high efficiency furnace is a heating system that converts the majority of its fuel source into energy while minimizing losses or wasted heat.

How does a High Efficiency Furnace Work?

The key to furnace efficiency is the second heat exchanger. A traditional furnace draws in cold air, heats it inside the combustion chamber and blows the warm air out into the home through ductwork. In a traditional furnace, some of the heat that could be used in the home escapes with exhaust gasses.

A high efficiency furnace adds a second heat exchanger that captures more energy from the exhaust gasses before venting them outside. Many high efficiency furnaces are also designed with a sealed combustion chamber that reduces possible heat loss. They also use multi-stage burners and variable speed blowers to run at a range of settings, reducing energy waste. Paired with a smart thermostat, a high efficiency furnace can lower heating bills significantly.

What is AFUE?

Annual Fuel Utilization Efficiency (AFUE) is the measurement that indicates how high efficiency a furnace is. AFUE is calculated by dividing an appliance’s yearly heat output by its yearly fuel consumption over a set time period, usually one year. The higher the percentage of efficiency, the more energy saving your high efficiency furnace.

AFUE ratings range from 0 percent to 100 percent, with higher amounts indicating greater efficiency in converting fuel into useful heat.

Additional reading: AFUE Rating Explained: What is a Good AFUE Rating?

What is the difference between an 80 vs 95 AFUE furnace?

When shopping for furnaces, you’ll often see numbers like 80 percent or 95 percent. These numbers refer to the AFUE that we discussed above. For every dollar spent on heating costs, an 80 percent high efficiency furnace uses eight-tenths of every BTU to heat a home.

A furnace with a 80 to 83 percent AFUE efficiency rating is considered a mid-range efficiency furnace with 80 percent being the minimum allowed by the Department of Energy. High efficiency furnaces are typically between a 90 and 98 percent AFUE rating and include features like two heat exchangers, variable speed fans, sealed combustion chamber, and smart controls.

Reasons to Buy a High Efficiency Furnace

Benefits of high efficiency furnaces include:

  • They use less energy, which can save you money on your monthly utility bills.
  • They help reduce your carbon footprint by emitting less greenhouse gasses, making them environmentally friendly.
  • They are able to run longer and at lower fan speeds, making them less noticeable and offering better overall indoor comfort.
  • They often have longer lifespans than traditional furnaces, as long as they are properly maintained.

What is the Difference Between a Gas furnace and an Oil furnace?

The type of fuel may actually have a big impact on operating costs so it is worth it to consider the differences between a gas furnace and an oil furnace. Both deliver heat to your home but, due to the nature of each fuel, produce warmth in slightly different ways.

Gas Furnaces Pros and Cons

Gas furnaces rely on natural gas as the primary energy source. Here are some things you should know about gas furnaces:

  • Cleaner burning than other types of home heating options
  • Natural gas is typically available and affordable in most Portland areas
  • Across the United States, over 50 percent of homes use natural gas to heat.
  • AFUE ratings are between 80 and 98.5 percent
  • They are less maintenance than oil
  • Produces less BTUs than oil
  • Require regular checks for gas leaks
  • Gas furnaces (with installation) can be more expensive than oil

Oil Furnaces Pros and Cons

Oil furnaces are often less expensive than high efficiency gas furnace models because they tend to be less efficient with AFUE ratings between 84 and 90 percent. Let’s take a look at some other pros and cons of oil furnaces:

  • Provide more heat per BTU than any other fuel
  • Very safe and stable fuel
  • Time-tested fuel and furnaces and can last a long time with regular maintenance
  • Not limited to pipelines like natural gas
  • Lower AFUE ratings
  • Less stable pricing
  • Needs space for a fuel tank
  • Requires additional maintenance and cleaning due to oil residue
  • Need to sign up for regular delivery

What is the Environmental Impact of a Gas Furnace?

Gas furnaces are a high-carbon fuel source and if the combustion chamber is not properly sealed, it can leak carbon dioxide into your home. Also, when natural gas burns, it releases greenhouse gasses that contribute to climate change. However, high efficiency gas furnace models tend to be more environmentally friendly than older, low efficiency options because they waste less energy. Natural gas is also one of the cleanest burning fossil fuels.

Things to Consider for Your Gas Bill

Most people want to know how much their gas bill will go down with a high efficiency furnace. And the answer is: it depends. High efficiency furnaces can certainly bring down your heating bill, but if you keep your house at 75 degrees in the winter you are going to be using a lot of gas. Other factors are:

  • Window insulation. Do your windows leak air?
  • Weather. Is it an extra cold winter?
  • Doors. Does your door have effective weatherstripping?
  • Ductwork. Has your ductwork been inspected for leaks?
  • Filters. Dirty filters will reduce efficiency and make the furnace work harder.

How Much Does a New Furnace Cost?

Costs of high efficiency furnaces vary depending on the make and model, but they tend to be more expensive than traditional models. However, high efficiency furnaces will save you money in the long run.

On average, high efficiency gas furnaces with furnace installation from an HVAC company can cost between $6,000 and $10,000. This number does not include additional costs for any ducting.

Additional reading: How Much Does it Cost to Replace a Furnace?

What Size Furnace Unit Do You Need?

The cost of replacing a furnace can depend on a number of factors including the size of the furnace you need. Determining furnace size means considering:

  • Size of the home.
  • Number of people or pets in the home.
  • How many levels or stories are in the home.
  • Window directions.
  • Where the furnace will be installed.
  • Efficiency/comfort needs.
  • Type of furnace.

A professional HVAC consultant can help determine the right size of furnace for your home and comfort.

Are High Efficiency Furnaces Worth It?

There are many benefits to a high efficiency furnace but whether it is the right investment for you depends on what your goals are. If lower energy bills, reduced carbon footprint, and a longer life span are what you are looking for then the extra upfront cost is worth it.

This is especially true if it is time to replace your furnace and you plan to be in your current home for a long time. Over the high efficiency furnace’s lifetime the continual savings, longevity, and lower heating costs will bring a return to your wallet and you can feel good about reducing your carbon footprint.

How Long Does a Furnace Last?

The average high efficiency furnace lasts between 15 and 20 years. If your furnace is over a decade old, it may be time to consider installing a high efficiency model. You will start to notice an increase in gas bills around this age as the efficiency of older models deteriorates with age.

How Often Should You Service Your Furnace?

Regular maintenance is always going to be the best way to keep your high efficiency furnace working at its highest capacity. We recommend servicing once a year at the beginning of the fall season – before you turn on your furnace for the winter.

Getting your furnace ready to run will ensure you get the most benefit out of high efficiency technology and prevent an emergency repairs from being needed when cold weather is upon us in the Portland area.

Additional reading: 10 Warning Signs Your Furnace Needs to Be Serviced

Should I Replace My Old Unit with a High Efficiency Furnace?

If your current furnace has been around for more than 10 years, it may be time to consider replacing your old furnace with a high efficiency unit. In addition, if you have had frequent repairs or expensive repairs on an older furnace, this is also a sign that it is time to consider a new heating unit.

Signs it is Time to Replace Your Furnace

There are a number of reasons to consider replacing your furnace.

  • Furnace is making unusual noises
  • Energy bill has increased
  • Uneven heating throughout your home
  • Frequent repairs
  • Furnace is over 12 years old
  • Cycling frequently

An HVAC professional can walk you through options and help you decide when it is time to replace your furnace.

Additional reading: How Long Does a Furnace Last & When to Replace It

How Jacobs Can Help

High efficiency furnaces are a great long-term investment saving you on annual heating costs and reducing your carbon footprint.

When it comes to any part of your HVAC system, you want a company that has the experience and knowledge to help you make informed decisions. Jacobs Heating & Air Conditioning experts are here to guide you.

If you’re interested in installing a high efficiency furnace in your Portland, Oregon, or Vancouver, Washington home, contact Jacobs Heating and Air Conditioning to talk to a HVAC consultant about options. No matter what you need we’re always just a phone call away. You are welcome to review our statement on COVID-19 and how we’re taking precautions to protect you, our team, and our communities.

About the Author

Amanda Jacobs portrait

Amanda Jacobs, Internal Project Manager

Amanda Jacobs is an Internal Projects Manager and 3rd generation member of Jacobs Heating & Air Conditioning. She received her MBA from Seattle University and has worked for a leading HVAC training and consulting firm. When not talking HVAC on the Jacobs Blog, you can find her on the golf course or whipping up her famous vegan chili.