A Guide to High-Efficiency Furnaces

by | Apr 5, 2024 | HVAC, Heating, Furnace

High-efficiency gas furnaces have improved technology compared to standard-efficiency ones. In the following, we will examine their differences. 

The purpose of this article is to demystify the HVAC process. Technicians and salespeople use industry terms regularly. However, sometimes the lingo can go over a customer’s head. 

Two-stage. Variable-speed. AFUE. BTUs. Modulating. Air Handler.

When we meet with a homeowner, we always define unfamiliar terms. We do this because purchasing expensive heating or cooling equipment should make perfect sense. Customers should know every step of the process, or they will not know what we’re talking about and will not be able to make an informed purchase. 

First, we will explain one of the more common terms and why it matters: high efficiency. 

What Is a High-Efficiency Furnace?

There are two main furnace types: gas furnaces and electric furnaces. 

Although propane and oil furnaces are still available, they both fall into the “gas furnace” category. If you still have a propane or oil furnace and access to natural gas, switching to gas would go a long way toward lowering your heating costs. 

Electric furnaces are, by definition, high-efficiency furnaces — even though we don’t really call them that. The reason it’s considered high efficiency is because every cent you put into getting the hot air is used. There’s nothing wasted, nothing to exhaust away from the furnace or the home. Everything is used.  

Most electric furnaces consist of an air handler that has heating coils added to it (it is sometimes called a heat package or heat strips). Electric furnaces work similarly to a toaster, only on a much larger scale. The heated coils act in much the same way, glowing red when they’re hot. If there were an airstream flowing through your toaster, pushing the warm air into your home, you’d have a miniature electric furnace. 

Additionally, gas furnaces can also be high efficient depending on the model and make. 

So when we talk about the definition of efficiency, we’re talking about the differences in gas furnaces: There’s the standard-efficiency furnace versus a high-efficiency unit. High-efficiency furnace rates typically fall anywhere between 90% and 98% AFUE. Anything less than 90% is standard efficiency. 

How is Furnace Efficiency Measured?

Furnace efficiency is typically measured by its Annual Fuel Utilization Efficiency (AFUE). The AFUE rating is a percentage that reflects how much fuel a furnace converts into usable heat over the course of a year. For instance, a furnace with an AFUE of 80% means that 80% of the fuel is utilized for heat, while the remaining 20% is lost in the combustion process, often as exhaust. Thus, the higher the AFUE rating, the more energy-efficient the furnace is considered to be. 

AFUE is an important factor to consider when purchasing a furnace. A higher AFUE rating can mean significant cost savings in the long run, as it indicates that the furnace is using less fuel to produce the same amount of heat. This not only reduces energy costs but also helps to reduce carbon footprint and promote environmental sustainability. 

How Does a High-Efficiency Furnace Work?

A high-efficiency furnace operates by making optimal use of fuel to generate heat, thereby reducing wastage and maximizing output. Unlike traditional models, these furnaces incorporate a secondary heat exchanger to extract heat from the exhaust gases that would otherwise be vented outside. This condensation process releases additional heat, which is then circulated through the house. Furthermore, high-efficiency furnaces often feature sealed combustion, meaning air from outside is used for combustion, resulting in safer operation and reduced heat loss. Thus, through these advanced mechanisms, high-efficiency furnaces achieve superior performance, reducing energy consumption and lowering utility bills. 

High-efficiency furnaces benefit homeowners in terms of cost savings and have a positive impact on the environment. By using less fuel to produce the same amount of heat, these furnaces emit fewer greenhouse gases and reduce their carbon footprint. In fact, according to the U.S. Department of Energy, replacing an older furnace with a high-efficiency model can reduce carbon emissions by up to 1.5 tons per year. 

Moreover, high-efficiency furnaces often have a longer lifespan compared to traditional models, making them a more sustainable option in the long run. They also require less maintenance and repair, reducing the overall environmental impact. 

In addition to being environmentally friendly, high-efficiency furnaces offer improved comfort. 

Standard-Efficiency vs. High-Efficiency Gas Furnaces

Furnace efficiency is measured by the ability of the heating system to generate warm air that is being used to heat your home versus how much is being exhausted as waste. In furnaces, we’re trying to keep as much of the BTUs as possible, BTU stands for British Thermal Unit; One BTU refers to the amount of energy required to increase the temperature of a pound of water by 1° F. 

While no gas furnace is 100% efficient, the higher the number, the more efficient the unit. To be considered high efficiency, the rating needs to be between 90 percent and 97 percent.  

The best high-efficiency furnaces are up to 97 and 98 percent efficient. The standard efficiency is only 80 percent. This means 80 percent of the heat is used, while 20 percent is being exhausted as waste. 

If it’s more efficient, on the other hand, it won’t have to generate as much heat to do the same job. 

What Is the Waste Created by a Gas Furnace?

While efficient in heating, a gas furnace does generate various types of waste. Most notable is the production of carbon dioxide (CO2), a greenhouse gas contributing to climate change. Incomplete combustion can also lead to the formation of carbon monoxide (CO), a hazardous gas. Additionally, a gas furnace produces water vapor and small amounts of sulfur dioxide and nitrogen oxides, which can contribute to acid rain. It’s essential to have efficient and well-maintained furnaces to minimize these waste products. 

For decades, gas furnaces have been a popular choice for heating homes and buildings. They are relatively low-cost, efficient, and can quickly heat large spaces. However, as with any type of fuel combustion, some form of waste will always be produced. 

One of the most significant concerns with gas furnaces is their contribution to greenhouse gas emissions. Carbon dioxide (CO2) is the primary greenhouse gas responsible for trapping heat in the Earth’s atmosphere, leading to climate change. Gas furnaces produce CO2 as a byproduct of combustion, contributing to the overall emissions from residential and commercial buildings. 

Moreover, incomplete combustion in gas furnaces can produce carbon monoxide (CO), a colorless and odorless gas that can be deadly in high concentrations. This is why it’s crucial to have regular maintenance and inspections for gas furnaces to ensure they are burning fuel efficiently and not producing dangerous levels of CO. 

Which Furnace Heats Better: Gas or Electric?

When it comes to heating efficiency, both gas and electric furnaces have their advantages. A gas furnace uses natural gas to heat your home and is considered more energy-efficient, as it can quickly heat up a room without using a lot of fuel. On the other hand, electric furnaces are more efficient in terms of converting energy to heat. However, the cost of electricity tends to be higher than natural gas in many regions, making electric furnaces a more expensive option in the long run. Therefore, the choice between a gas and electric furnace often boils down to the specific requirements of your home, as well as the relative costs of gas and electricity in your area.  

Gas furnaces are typically recommended for larger homes or colder climates, as they provide a higher heating capacity and can heat up your house quickly. Additionally, gas furnaces are more reliable in terms of providing consistent heat, as they do not rely on electricity to operate. This is especially important in areas prone to power outages during winter storms. 

On the other hand, electric furnaces are a better option for smaller homes or milder climates, as they do not require a lot of space for installation and can be easily accessed for maintenance. Electric furnaces also have fewer moving parts, making them less prone to breakdowns and requiring less maintenance overall. 

Learn more about Gas Furnaces vs. Electric Furnaces

What Is the Environmental Impact of Gas Furnaces?

Gas furnaces, while efficient in heating homes, have a considerable environmental impact. The combustion process in gas furnaces releases carbon dioxide, a potent greenhouse gas that contributes to global climate change. Additionally, natural gas extraction and transportation can lead to methane leaks, another powerful greenhouse gas. Moreover, inefficient furnaces or those in need of maintenance can produce carbon monoxide, a harmful gas, when inhaled. Despite advancements in technology making gas furnaces more efficient and eco-friendly, their operation still contributes to greenhouse gas emissions and global warming. 

A significant factor in gas furnaces’ environmental impact is their reliance on fossil fuels. As we now know, burning fossil fuels releases large amounts of carbon dioxide into the atmosphere, where it traps heat and contributes to global warming. With a growing awareness of climate change and its consequences, it’s becoming increasingly crucial to consider alternative ways to heat our homes. 

Will a High-Efficiency Furnace Save Me Money in the Long Run?

A high-efficiency furnace can indeed save you money in the long run. These types of furnaces are designed to minimize energy waste, using less fuel to heat your home compared to traditional models. This results in lower heating bills over time. Moreover, they are often eligible for energy efficiency rebates, which can further offset their initially higher purchase cost. However, the exact amount of savings will depend on various factors, such as the size of your home, the climate in your area, and the cost of fuel. Therefore, it is recommended to consult with a professional HVAC technician to determine the best solution for your specific needs. 

Additionally, high-efficiency furnaces are also better for the environment. As they use less fuel, they produce fewer emissions and contribute less to air pollution. This can significantly reduce our carbon footprint and preserve the planet’s natural resources. By opting for a high-efficiency furnace, you are not only saving money but also doing your part in promoting sustainability and reducing greenhouse gas emissions. 

In terms of performance, high-efficiency furnaces provide better temperature control and even heat distribution throughout your home. This is because they have advanced technologies such as variable-speed blowers and modulating burners, which adjust the amount of fuel burned based on the heating demand. This results in a more consistent and comfortable indoor temperature without any sudden spikes or drops. 

Moreover, high-efficiency furnaces often come with additional features such as smart thermostats and zoning systems. These systems allow you to customize your home’s heating usage according to your schedule and preferences. These features not only add convenience but also contribute to further energy savings. 

Lastly, investing in a high-efficiency furnace can also increase the value of your home. As energy efficiency becomes increasingly important for homeowners, having a high-efficiency furnace can make your property stand out in the market. This can potentially lead to a higher resale value and attract potential buyers. 

In conclusion, while high-efficiency furnaces may have a higher upfront cost, they offer numerous benefits in the long run. From cost savings and environmental impact to performance and home value, they are a wise investment for homeowners looking to upgrade their heating systems. So why wait? Consult with an HVAC professional today and see how a high-efficiency furnace can improve your home’s comfort, efficiency, and overall value.  

A High-Efficiency Furnace Doesn’t Always Mean Better Comfort

Some people just want high efficiency because it sounds nicer. Nevertheless, it may not solve the concerns you have about your current home heating system, especially if you have cold spots in your home in the winter. Installing a high-efficiency furnace isn’t going to solve that. Efficiency doesn’t always matter when it comes to comfort. Two-stage or variable-speed furnaces circulate air better and create less dry heat. Air blowing over the heat strips tends to produce dry air. You get more control over the circulation of the airflow so that you can adjust better. 

Cost of a Furnace Replacement

So, what are the actual price ranges? 

Mid-Efficiency Furnace (~80%) 

  • Single-stage: $3,495-$5,995 
  • Two-stage: $4,095-$7,395 
  • Two-Stage Variable-speed: $4,995-$9,395 

High-efficiency Furnace (90%+) 

  • Single-stage: $4,795-$8,395 
  • Two-stage: $5,295-$8,795 
  • Two-Stage Variable-speed: **$6,195-$10,295** 
  • Modulating 98% (variable-speed): $6,695-$11,595 

This includes installation and related fees. It does not include ductwork, ventilation modification, or indoor air quality add-ons. 

Take the Next Steps

Hiring a local, experienced, and trusted HVAC partner like Five Star Home Services makes all the difference! We can help you make the best decision if you are looking to install a new furnace in your home. Call us today at (833) 405-8009.

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