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Understanding the Difference: 95% vs. 80% Furnaces

Updated: Oct 12, 2023

When it comes to choosing a new furnace for your home, efficiency is a key factor to consider. Furnaces are available in various efficiency ratings, and two common options are 95% and 80% furnaces. Understanding the differences between these two types can help you make an informed decision that aligns with your heating needs and energy-saving goals. In this blog post, we'll explore the disparities between 95% and 80% furnaces, shedding light on their performance, benefits, and considerations.

Trane high efficiency furnace
Trane high efficiency furnace

1. Efficiency Ratings:

The primary distinction between 95% and 80% furnaces lies in their efficiency ratings. Efficiency is measured as the Annual Fuel Utilization Efficiency (AFUE) percentage, which represents the amount of fuel a furnace converts into usable heat. In simple terms, the higher the AFUE rating, the more efficient the furnace is at converting fuel into heat.

- 95% Furnaces: A 95% furnace has an AFUE rating of 95%, meaning it converts 95% of the fuel it consumes into heat, while losing only 5% as waste. These highly efficient furnaces provide exceptional energy savings and can significantly reduce your heating costs compared to less efficient options.

- 80% Furnaces: On the other hand, 80% furnaces have an AFUE rating of 80%. They convert 80% of the fuel into heat, while 20% is lost as waste. Although not as efficient as their 95% counterparts, 80% furnaces still offer considerable energy savings compared to older, less efficient models.

2. Performance and Comfort:

Both 95% and 80% furnaces are capable of effectively heating your home, but there are some performance differences to consider.

- Consistent Heat: 95% furnaces provide more consistent heat output due to their higher efficiency. They can maintain a more stable temperature throughout your home, resulting in improved comfort and reduced temperature fluctuations.

- Enhanced Air Quality: 95% furnaces typically have advanced air filtration systems that can help improve indoor air quality. These systems can trap and filter out dust, allergens, and other pollutants, creating a healthier living environment.

3. Venting Requirements and Installation:

Another key aspect to consider when comparing 95% and 80% furnaces is their venting requirements and installation considerations.

- 95% Furnaces: Due to their higher efficiency, 95% furnaces use a condensing technology that produces condensation during the heating process. As a result, they require a special venting system to handle the acidic condensate. This may involve additional installation costs, but the long-term energy savings can offset these expenses.

- 80% Furnaces: Unlike 95% furnaces, 80% furnaces do not produce condensation and can use a conventional venting system. This makes them easier and less expensive to install, as they can often use the existing venting infrastructure in your home.

4. Cost Considerations:

Cost is an important factor for many homeowners when deciding between 95% and 80% furnaces.

- Purchase Price: 80% furnaces generally have a lower upfront purchase price compared to their higher efficiency counterparts. This can make them an attractive option for those with budget constraints or in milder climates where the heating demands are not as high.

- Long-term Savings: While 80% furnaces may have a lower initial cost, it's essential to consider long-term energy savings. 95% furnaces can provide significant savings on utility bills over their lifespan, potentially making them a more cost-effective choice in the long run.


When choosing between a 95% and 80% furnace, it's important to consider your heating needs, energy-saving goals, and budget. While 95% furnaces offer superior efficiency, improved comfort, and long-term savings, 80% furnaces still provide notable energy savings and a more budget-friendly option. Consulting with a professional HVAC technician can help you assess your specific requirements and make an informed decision that meets both your comfort needs and financial considerations. Remember, no matter which furnace you choose, regular maintenance and proper installation are key to ensuring optimal performance and efficiency.


Salmark HVAC


Lemont, IL

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