Where you aware that more than half of your home’s energy costs are for your heating and cooling? That’s why it’s essential to secure an energy-efficient HVAC system.

Furnace efficiency standards were last revised to an Annual Fuel Utilization Efficiency (AFUE) rating of 80% in 2015. This rating system illustrates how effective your furnace is at natural gas into heat. An AFUE rating of 80% means your furnace will waste about 20% of the fuel it uses while producing heat.

In 2022, President Biden revealed new energy-efficiency standards for residential gas furnaces that would significantly decrease emissions, save consumers money and promote sustainability.

This proposal is projected to:

  • Save Americans $1.9 billion annually.
  • Reduce carbon emissions by 373 million metric tons and methane emissions by 5.1 million tons over the next 25 - 30 years, the equivalent of what 61 million homes emit each year.

Starting in 2029, the updated rule would require all new gas furnaces to feature AFUE ratings of 95%. This means furnaces would turn nearly 100% of the gas into usable heat.

Considering these guidelines, you might be asking yourself what does that mean for my existing furnace? Currently, not much, as the proposed rule wouldn’t go into effect until 2029 at the earliest and doesn’t affect furnaces that are already in use.

But if you are considering furnace replacement in soon, highly energy-efficient furnaces are already available. Find out how these furnaces can help you save on energy bills now.

Guide to Condensing Furnaces

How Condensing Furnaces Work

A condensing furnace is a type of heating system that uses a secondary heat exchanger to collect wasted heat from the furnace's exhaust gases. This limits the amount of energy wasted, enhances energy efficiency and lowers CO2 emissions. It also will take less natural gas to create the same rate of heat when comparing one to other types of furnaces.

How Condensing Furnaces Differ from Non-Condensing Furnaces

The main difference between a condensing furnace and a non-condensing furnace is condensing models use a secondary heat exchanger to capture any wasted heat from its exhaust gases, while the latter does not.

Equipment Lifespan

The life span of a condensing furnace will depend on the brand, model and other factors. Generally speaking, a condensing furnace should last between 10-20 years with sufficient maintenance and regular service. If you put off scheduled maintenance, the unit may have a significantly shorter life span.

Why Condensing Furnaces Are More Expensive

Usually, condensing furnaces enhanced precision is much more efficient than traditional furnaces, as it only utilizes the minimum amount of energy necessary to heat your home, which  subsequently saves money on your utility bills.

Most variable-speed furnaces are condensing furnaces, although a handful are available in non-condensing models with lower AFUE ratings. If a manufacturer wants a furnace to be classified as a condensing furnace, it must offer an AFUE rating of 90% or higher.

Do Variable-Speed Furnaces Run All the Time?

A variable-speed furnace doesn’t run all the time. Rather, it runs at different speeds according to the temperature in your home as well as the amount of energy it needs to reach that temperature.

When sufficient energy is required to maintain your set temperature level, the furnace will switch to a higher speed in order to keep up with demand. This allows for more efficient heating in your home while also offering quieter operation.

Guide to Two-Stage Furnaces

Two-Stage Furnaces: What They Are and How They Work

As the name suggests, a furnace with two levels of operating (high or low) is called a two-stage furnace. On the low stage, the furnace runs at a reduced capacity as a way to maintain the chosen temperature in your home more efficiently. During the high stage, the furnace will instead function at peak capacity to meet demands for greater heat. With a two-stage furnace, you can experience greater energy efficiency and consistent temperatures all across your home.

While two-stage furnaces are very efficient, not all all models are condensing furnaces.

Does a Two-Stage Furnace Run All the Time?

A two-stage furnace won’t run all the time. In the low stage of operation, the furnace performs at diminished capacity in order to sustain a desired temperature more efficiently within your home. When additional energy is needed to reach the set temperature, the heating system will switch to its high stage and operates at full capacity. For this reason, two-stage furnaces are proven to help reduce energy costs without operating constantly.

Comparing Two-Stage and Variable-Speed Furnaces

Two-stage furnaces have two stages of operation, low and high. During the low stage, the furnace runs at reduced capacity as a way to sustain a desired temperature within your home. When a greater demand for warmth or cooling is desired, the furnace will switch to its high stage and operate at full capacity.

Variable-speed furnaces, meanwhile, can function at several speeds in order to sustain a more precise temperature at home. Such precise functionality can also help reduce energy costs, as it is not constantly running on full power like many two-stage furnaces do.

Differences Between One- and Two-Stage Furnaces

One-stage furnaces have a single stage motor and operate either at full capacity or not at all. This means that the furnace is always running in order to maintain a desired temperature within your home.

Conversely, two-stage furnaces have two stages of operation, low and high. While in the low stage, the furnace runs at [lower|reduced} capacity in order to maintain the desired temperature more efficiently. When more warmth or cooling is desired, the furnace will shift to its high stage and operate at peak capacity.

Arrange Your Furnace Install Appointment with May's Heating & Air Today

It takes experience and dedication to stay up to date about furnace technology advancements. That’s why May's Heating & Air professionals are here to help with a no-cost, no-pressure estimate for furnace installation. We’ll assess your home, your heating requirements and your budget before helping you find the ideal solution. Get in touch with us at to get started today!