What are the standards for an energy-efficient furnace?

man fixing energy efficient furnace

When it comes to heating our homes, many people worldwide have no other option during the cold winter. Whether they choose an energy source of wood, gas, electricity, or another option depends on various factors, including location. In the United States, most people heat their homes with an energy-efficient furnace powered by gas or electricity. However, some still rely on burning wood or coal.

Regardless of the fuel source, heating properties can be an expensive endeavor. Not only is the equipment a costly investment, but many furnaces – especially older models – are not as energy efficient as property owners would prefer, causing fuel bills to rise while they are in use. Since heating is hardly optional when temperatures drop below freezing levels, choosing the most efficient furnace is in every property owner’s best interest.

Likewise, the U.S. Department of Energy has a vested interest in conserving the energy used by people around the country. It sets standards for various equipment and appliances, requiring that they meet minimum efficiency standards and other metrics. Periodically, the DOE revises these standards in its efforts to boost Americans’ energy conservation.

What are the current energy efficiency standards for furnaces, and will they increase more in the future? How do they affect HVAC professionals and property owners? Read on for these answers and more.

History of Energy-Efficient Furnaces

Americans have been heating their homes in one form or another throughout history. Still, it’s only been in recent decades that legislation has regulated furnace efficiency. California enacted the first standards in 1974. The following year, the federal government established policies for consumer product test procedures, labeling, and energy targets. In 1979, the government amended the Energy Policy and Conservation Act to direct the DOE to design energy conservation standards for consumer products, including furnaces and other HVAC equipment.

It took a few years, but the National Appliance Energy Conservation Act of 1987 eventually established minimum efficiency standards for household appliances like furnaces. At that time, Congress set the first federal standards for an energy efficient furnace. Changes included a rule that new furnaces be at least 78% efficient, creating a schedule for the DOE to review and update the standards in future years.

Congress made multiple attempts to increase the minimum efficiency of furnaces further over the years, but most were either amended or blocked. In 2007, through the Energy Independence and Security Act, the DOE raised the minimum efficiency for new furnaces from 78% to 80%. That’s when things got a little tricky.

At the time, most furnaces on the market already met the went into effect in 2015. Therefore, the changes wouldn’t drive much difference in the market. Lobbyists pressured Congress for even more stringent standards, especially in climates with greater furnace use. As a result, Congress divided the country into regions and proposed new regional standards: 90% in cooler climates but just 80% in warmer climates. That rule, however, was also challenged, leaving the national standard at 80% until the present day.

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Current U.S. Furnace Standards

Aside from price, efficiency is at the top of most consumers’ lists when shopping for a new furnace. After all, the efficiency will dictate monthly budgets for years as the furnace requires either more or less energy. Unlike many other HVAC appliances that use the Energy Star rating system to define efficiency, furnaces are rated according to their Annual Fuel Utilization Efficiency. Understanding the AFUE rating system will help consumers choose the most cost-effective HVAC equipment and energy efficient furnace to heat their homes and properties.


What is AFUE?

What is the Annual Fuel Utilization Efficiency? The furnace rating system measures how much of the equipment’s fuel is used to heat a building. The higher the AFUE rating, the greater the furnace’s efficiency. For example, if a high-efficiency gas furnace is rated with an AFUE of 96%, it creates 96 BTUs of heat for every 100 BTUs of gas it uses. All electric furnaces have a 100% AFUE.

Minimum Efficiency Ratings

What are the current minimum efficiency standards for U.S. furnaces, and how are most furnaces ranked? Since 2015, residential gas furnaces must have a minimum AFUE of 80%. However, that doesn’t mean most consumers choose furnaces at that rating.
To be considered a high-efficiency furnace and awarded the Energy Star Label, a furnace must have an AFUE of 90% or higher. Many modern gas furnaces have efficiency ratings as high as 98.5%.

Will the Department of Energy increase furnace standards?

Despite many failed attempts over the last few decades, will the DOE again attempt to increase furnace efficiency standards? In 2022, the DOE proposed new residential efficiency standards for gas furnaces. Under the regulation, gas furnaces for use in residential buildings would have to be 95% fuel efficient. The rule would only apply to furnaces manufactured in or imported to the United States starting in 2029. According to the DOE, stricter efficiency standards would save consumers $30.3 billion over 30 years.
A proposal, however, does not mean the new standards will ever become law. At least two major industry organizations objected to the changes, citing potential issues with building modifications, among other concerns. What will happen moving forward? Only time will tell.


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