Natural gas is the most common way to power a furnace.
That’s why all major brands – from Carrier, Trane, American Standard to Lennox – are racing to create the best gas furnaces.
That race is pretty much just about one thing:
Energy-efficiency. Why?
Well, the biggest selling point of gas furnaces is that they have the lowest running cost. For example, to create 1,000,000 BTU of heating, we need:
- Electricity: $38.66. Average heating season cost: $2,226.82.
- Heating oil: $27.16. Average heating season cost: $1564.42.
- Natural gas: $13.05. Average heating season cost: $751.68.
Just by using natural gas, we can save almost $1,500 per heating season compared to the electric furnace heating.
The very low running cost is due to the low price of natural gas compared to heating oil and, especially, electricity.
The best way to create a superior gas furnace is to design one which can extract as much energy as possible from every single cubic inch of natural gas. The race to increased efficiency started in the 50s. Here is how we got here:
- The 1950s: Old standing pilot oil furnaces have 50% – 60% energy-efficiency (top AFUE rating was 60).
- The 1970s: Natural draft gas furnaces have a 65% energy-efficiency (65 AFUE rating).
- The 2000s: Forced vent furnaces increase energy-efficiency to 80% (which was outstanding at the time).
- The 2010s: Invention of condensing gas furnaces capable of up to 90% energy-efficiency.
- 2015 and on: Upgraded condensing unit (multi-stage burners, outside combustion air, multi-speed fans) skyrocketed the energy efficiency to at much as 97% (97 AFUE rating).
Basically, we live in the golden age of gas furnaces. The most advanced units have come extremely close to 100% efficiency.
For every 1$ of gas, we get $0.97 of heating energy.
Before, people had to upgrade their gas furnaces. Now, with 97% efficiency units, you know you won’t have to upgrade your unit, and it will easily serve you well for 20 years.
The best example of how gas furnaces have advanced is the Goodman 80, 000 BTU 96% efficiency upflow/horizontal gas furnace (GMSS960803BN model). It’s a masterpiece of modern gas furnace engineering and arguably the best affordable gas furnace in 2023:
Here’s the deal:
We will quickly go over the 3 vital things you need to know before calling an installer for estimates. In the end, you’ll find a table of the best gas furnaces, with unit prices and installation costs. We’ll also reveal how you can easily get 4 free estimates from gas furnace installers in your area.
3 Things To Know Before Calling A Gas Furnace Installer
Before you start getting estimates for furnace installation, it’s important to understand the basic principles that affect the overall heating costs.
We’ve also figured out that energy-efficiency is the most important specification. We’ll calculate how much better the 97 AFUE gas furnace is compared to the 80 AFUE one.
Additionally, we’ll look at key features to look for when buying a new gas furnace. Most of them are designed to increase energy-efficiency and to stabilize the indoor temperature during the winter.
What is even more important, we’ll check which are the most reliable HVAC brands that offer gas furnaces.
Gas Furnace Energy Efficiency (AFUE Rating)
The intense race to create the most high-efficiency gas furnace might not be apparent at first. As will all furnaces, this is how we can calculate the overall cost of a gas furnace:
Total Gas Furnace Cost = Unit Cost + Installation Cost + Gas Cost
When we’re looking for a new gas furnace, we usually focus on the unit price and installation price. But what really matters in the long-turn (10-25 years) is how efficient the unit is.
The reason is simple. Here is the distribution of costs:
- Unit cost: 10%.
- Installation cost: 20%.
- Gas cost: 70%.
Those $3,000-$6,000 costs of a gas furnace and $6,000-$10,000 installation cost is nothing compared to the gas cost. If we buy a very ineffective unit, we’re looking to spend $50,000 just on gas in 20 years. How much can we save by investing in a high-efficiency furnace? Let’s look at the following example.
Example: We have two 100,000 BTU gas furnaces. The first one has 80% efficiency (80 AFUE) and the second one has 97% efficiency (97 AFUE). If we run them for 720 hours per season, with an average price of residential natural gas (source: statista.com, 2019 prices) $10.60 per 1,000 cubic feet, we get:
- 80 AFUE gas furnace: 86.79 thousand cubic feet, which costs $919.97/season.
- 97 AFUE gas furnace: 71.58 thousand cubic feet, which costs $758.75/season.
According to the US Energy Information Administration, 1,000 cubic feet of natural gas contains 1,037,000 BTU of energy. 80 AFUE can extract 80% of that or 829,600 BTU. 97 AFUE can extract 97% of that or 1,005,890 BTU.
That results in a $161,22/season difference in natural gas cost in favor of 97 AFUE furnace. Here is how much you can save in 10 years and 20 years just by switching from 80% to 97% efficiency gas furnace:
- 10-year savings: $1,612.20.
- 20-year savings: $3,224.40.
It’s no wonder why so many people are replacing their old gas furnaces with new ones. Plus, the new ones have some extra features:
Features Of 2020 Gas Furnaces
To achieve +90% efficiency, the gas furnaces needed significant improvements. For 90% efficiency, the condensing unit is enough. To jump that extra 7 % (which can save you more than $1,000 in 20 years), the modern gas furnaces had to be equipped with extra features. These include:
- Variable-Speed Blower. In old furnaces, you one had 1 or, at best, 2 airflow settings. With a variable-speed blower, you can have several lower airflow settings. This adds to energy-efficiency and also reduced the noise levels.
- 2-Level Heating Capacity. In the 2000s, if you bought a 100,000 BTU gas furnace, you always had to run it on 100,000 BTU. Modern furnaces offer additional lower heat capacity settings. For example, you can run a 100,000 BTU unit on 100,000 BTU or 60,000 BTU (for sunnier winter days).
- Secondary heat exchanger. In addition to the primary heat exchanger, modern furnaces have a stainless steel second heat exchanger that pumps out additional BTUs from burning gas.
- HEPA Filters. People with lung diseases might be sensitive to a very low concentration of air pollutants. A HEPA filter is attached to the exhaust to minimize pollutants that might come out of a gas furnace.
When comparing gas furnaces, be mindful of these features. They are a true testament to the quality and good engineering that went into the design of the furnace.
Best Gas Furnace Brands
When checking the best electric furnace or best oil furnace brands, most homeowners expect to see big reliable brand names such as Lennox, Carrier, and Trane.
These big brands primary focus is the most popular type of furnace: the gas ones. When talking with your installer about gas furnaces, you can rest assured that you’ll already know all of the big brands with the longest tradition and best reliability scores.
The best big brands that sell gas furnaces are:
- Lennox. Unit price: $5,400. They have a 99 AFUE model SLP99UH090XV60C- that is even featured on ENERGY STAR for the most efficient furnaces.
- Trane. Unit price: $4,500.
- Ruud. Unit price: $4,400.
- American Standard. Unit price: $4,200.
- Carrier. Unit price: $3,900.
- Rheem. Unit price: $2,800.
It makes sense that only the big companies had enough resources to develop high-efficiency models. That why we don’t see many new and low-price gas furnace manufacturers. One lower price manufacturer worth mentioning is Bryant.
In recent years, Bryant has made some incredible leaps in designing high-efficiency gas furnaces. Their unit price can be as low a $2,500.
Gas Furnace Brand Comparison Table With Unit Prices And Installation Costs
As promised, we have summarized the best brand in a neat table. With each one, you’ll see the unit price to give you an idea of the prices you can expect.
What is more, we have called a few gas furnace installers to get free advice and quotes. The rough estimates of gas furnace installation costs are included in the table.
If you decide to buy a gas furnace, you can turn to these experts and ask them about a specific unit price and installation costs. They can even give you a discount if they are working with a certain brand. You can fill in a short form here and get 4 free quotes.
| Gas Furnace Brand | Unit Cost | Installation Costs |
|---|---|---|
| Lennox | $5,400 | $7,200 |
| Trane | $4,500 | $6,800 |
| Ruud | $4,400 | $6,400 |
| American Standard | $4,200 | $6,000 |
| Carrier | $3,900 | $5,400 |
| Rheem | $2,800 | $4,400 |
| Bryant | $2,500 | $3,900 |
If you have any questions regarding the energy efficiency of gas furnaces, you’re welcome to use the comment section below.
Since Bryant now gets a mention alongside Lenox, Rheem, etc, what are the cons? $3to4K In price is a REAL pro
Hello Jan, looking at the specs of Lennox vs Bryant furnaces, there is very little difference indeed. The one thing that’s a real con for Bryant is the tradition. HVAC devices such as gas furnaces last for 20+ years; we can evaluate how good they are if we’ve been using them for 30 or so years. More established brands do have a good track record while Bryant’s record is not truly there as of yet.
I think The best way to create a superior gas furnace is to design one which can extract as much energy as possible from every single cubic inch of natural gas. The race to increased efficiency started in the 50s. Also, It makes sense that only the big companies had enough resources to develop high-efficiency models. That why we don’t see many new and low-price gas furnace manufacturers. One lower-price manufacturer worth mentioning is Bryant.
Hi. I have an old furnace from 1984. It’s has 4 zones, with double 50gal boilers. It’s 38yrs old and still working.
So far I only had to replace 2 leaky zone valves. My gas bills fluctuate on what I set my thermostat.
I’d like to get a newer system but if it’s not broke why fix it.
I guess my question is, when should it be replaced? Do the new high efficiency furnaces use boilers also?
Do the new high efficiency furnaces last over 30yrs?
Thanks in advance.
Hello Michael, if it’s not broken why fix it is a good sentiment. The gas bill with the newer high-efficiency gas furnaces will definitely be lower (by quite a lot). Should it be replaced right now? Well, it doesn’t have to be, but in 10 years, you’ll probably have to replace it. During that time you can burn quite a lot of gas; with the newer furnace, you would start saving on gas right away.
High-efficiency furnaces can last for 30 years, they’re quite reliable. Of course, you can use a boiler with it. It would be best if you get some practical calculations; you can use this form here and talk to the furnace installation experts.
My furnace is the original from 1950; I moved in in 1994. I have never replaced it or even needed to repair it. Now it does heat only the downstairs of a small Cape and I have a different zone upstairs ( a boiler for heats the upstairs) so I can turn it down all night. It’s big and bulky and noisy and 60% efficient. I’m replacing it now since I want central air. It is true though that they don’t make anything like they used to. I replaced all the appliances- the refrigerator still chugging after 30+ yrs -but I know they won’t be around in decades as these were (neither will I;)
Not that I see. My Tempstar is 4 years old quite messed up. Tonight, it’s worthless as it isn’t running at all. So now that I’m doing research on models there are many “high-efficiency” models that have a lot of complaints about them. If I have to replace this (after 4 years!), I’m going to assume anything I purchase following will best last maybe 5 years before needing some sort of repair. Efficiency seems to have gone up a lot, but quality has dropped like a stone in water.
What are the 97 % gas furnaces that you listed above?
Hello Charles, Goodman is a good brand that is known for their 97% (AFUE 97) gas furnaces. Here is an example of their best selling 97% efficiency 60,000 BTU model: Goodman GCVM970603BN.
Looking to replace my oil furnace & received quotes on 2 different furnaces; Amana & Trane with both 80% & 96% efficiency. Prices are comparable but don’t know which a better furnace. Trane model is S9x1C080U5PS & Amana AMEC960603BN for 96% efficiency are the ones I’m leaning towards. Trane is a single draft blower & Amana is a double. Any recommendations?
Hello Dorene, definitely go for a 96% efficiency gas furnace, that’s a no brainer. Trane vs Amana is a hard choice, both are brilliant brands, maybe the Trane has a bit of an edge here.
As much as I would like to believe that efficiency is the number one goal in a furnace and air conditioning replace I am concerned about the quality in the products inside these units. We all know what manufacturers do to cut corners chasing the god of efficiency. $2000 difference in a furnace or air conditioning unit package tells me somethings are different. As a service tech for 40 years in the mechanical trades I made my living replacing inferior quality and poor installations that cost thousands with lawsuits in the millions. I want to purchase a new package but what components are made to a quality standard in a mid-level company that’s different in a low or high name brand company.
What components are in these units that have a history of failure or longevity? That’s what I think is important and no body says that on the web. Coils, fans, burners, blowers regulators, etc made by whom and where. Warranties are the same give or take but labor of $1000 to replace a part under warranty still cost $1000 in 2-10 years. Reliability in a car is similar.
An Audi is wonderful but the fixing it is expensive! The Saturn was cheap to drive but had numerous problems.
Hello Mark, this situation is well-understood and you’re right, it’s difficult to precisely go from unit to unit, break it apart and check it part by part. Chasing the god of efficiency is great but not if it comes at a cost of reliability and longevity. The best advice we can give you is to check bigger brands; they usually produce more reliable units than no-name brands and have a track-record for their models. It’s not much, hope it helps.
Is the installation cost shown above strictly installation or is it the unit and installation together?
Hello Kathy, the installation and unit cost are, unfortunately, separate. To get the most realistic idea how much unit + installation would cost, you can use this form and get 4 free quotes from vetted HVAC experts in your area.
Great article! Comparatively, Lennox is more expensive than Trane because of its exceptional quality and efficiency. So if you value efficiency & the environment then Lennox may be a better choice for you. When it comes to Lennox vs Trane, both are exceptional ac brands. Thanks
Hello, my installer want to use Fujitsu HVAC system, 75000 btu gas
furnace, 3 ton evaporator coil 3 ton outdoor condenser, 86% efficiency rating, for a 1650 square foot home in Massachusetts. He is charging me $7000 for all the work and the unit. First is Fujitsu a good HVAC system? will a 3 ton system be enough and is $7K a good price?
Hello George, Fujitsu is considered quite a reliable brand overall; they offer pretty decent furnaces. 75,000 BTU heating output is enough for a 1650 sq ft home. That comes down to about 45 BTU per sq ft, pretty much in line with how big a heater you need according to heating BTU calculator. All in all, $7000 for both the unit and the work is reasonable.
I have a Williamson Gas Saver furnace that was installed in 1986. It still works fine, but I’m not sure how efficient it still is. I live in zone 4 (southeastern Michigan) in a single story 696 square foot house. I wonder, since my house is small, if the prices of a new furnace will be lower.
Hello Kathy, most probably you have below 80% efficiency. Efficiency also decreases with years and right now you have a 35-year old furnace. This is pretty much how long furnaces last. Replacement seems like a good choice. You will most probably get a 95+ AFUE furnace which will decrease your heating costs by 20% or even 30%. The con is the upfront cost of the new gas furnace. The best thing is to put all the heating savings and new furnace costs on paper and see if it makes financial sense to replace it.
How good are carrier Furnaces? I don’t see much discussion. Are the not efficient?
Why is there such a discrepancy in the installation cost for different brand furnaces? Regardless of brand, wouldn’t the installation be pretty much the same?
Hello James, common sense would say that the installation prices should be the same. However, there are other factors to consider, such as installation difficulty, the number of HVAC experts with the knowledge of how to install a particular brand, and so on. It’s not just a simple ‘getting paid for the same job’ thing, it’s a bit of a supply and demand dynamics with these installation prices.
I’m building a 4200 sq ft house in Seattle, zone 4. What size natural gas forced air unit do I need and can I buy one and install it? It will be inside in the basement.
Hello Lori, that’s quite a big house in a colder climate. You will likely require a 120,000+ BTU furnace. For a more precise evaluation as well as buying and installing a furnace, you should fill out this form and you will get adequate furnace sizing, prices, and so on. Hope this helps.
My question contains several parts: 1) the furnace will be used at an elevation over 7200 feet using propane. Will a high AFUE rating merit consideration? I will install a wood burning stove in the house, both first floor and basement, how will that affect the selection of a furnace?
Hi William, the high altitude can affect the efficiency of burning propane due to lower oxygen. You can expect slightly lower than specified efficiency at 7200 feet. Still, it is a good idea to go for a higher AFUE rating furnace.
The wood burning stove would serve as a secondary heating system? From the heating BTU output point of view, the type of furnace doesn’t really matter; it just needs to deliver adequate BTU output. If you need 50,000 BTU output, for example, you can choose between 50,000 BTU propane, gas, and electric furnace.
Great report and feedback – thanks.
I have a 2-level 1950 house with the original workhorse HydroTherm furnace (110K btu and 79K btu heating capacity). Ground level is 1,000sf, 1st level is 500sf and basement is 900sf. We’re planning to stay 5-7yrs longer in this house so don’t want to over-invest but seeking efficiency and maintain resale value with a reputable system. I’m thinking 96% efficiency rating, 2-level heating and heat exchanger but feel price will be high – would Goodman/Ruud/Carrier be fair options or would you suggest stay with high efficiency and drop the 2-level heating and exchanger?
Hi Fabrizio, well, in the short term, electric furnaces are a more sensible investment since the up-front cost is lower. Gas furnaces are usually a better long term investment since heating with gas is much cheaper than heating with electricity (furnace-wise, heat pumps are another matter).
However, having a gas furnace will increase the resale value, since the initial investment is already paid, and you can increase the cost of the house due to this.
You have quite a dilemma here. Namely, 1 heat exchanger will be significantly cheaper than a 2 heat exchanger furnace. For a 20-year investment, 2-level heating makes a lot of sense. However, the real question here is if the future buyer will understand the advantages 2-level heating gives (lower gas costs in the next 15 years) and be willing to pay extra for that 2-level heating.
From our experience, not a whole lot of homeowners understand that extra efficiency the 2-level heating gives you, and are not all that enthusiastic to pay a premium for that. The safe choice here would be to go for high efficiency 1-level heating. You will pay less for it now, and, as far as future buyer is concerned, they care a lot more about location, condition of the house, and so on. 1-level vs 2-level heating is, I dare say, never a deal breaker. Hope this helps at least a bit in your decision making.