Intro: Avoid Furnace Buyer’s Remorse
Hey there, Jake Lawson here. With over two decades working hands-on in HVAC installation, repair, and system design, I’ve helped hundreds of homeowners choose the right heating system for their needs. One thing I’ve noticed is that buying a gas furnace can be overwhelming, confusing, and—if you’re not careful—costly.
You’re making a major investment in your comfort and your home’s energy future, so it’s critical to avoid the common mistakes that can lead to buyer’s remorse. I’ve seen homeowners overspend on the wrong unit, end up with higher bills, or even compromise safety—all because they didn’t know what to watch out for.
This blog covers the top 5 mistakes you should avoid when buying a new gas furnace—especially important if you’re considering the latest energy-efficient R-32 compatible models like the ones offered at The Furnace Outlet. From sizing to installation and incentives, this guide will help you navigate your purchase like a pro.
Mistake #1: Choosing the Wrong Size Furnace
Why Furnace Sizing Is a Big Deal
A furnace that’s too large or too small for your home can cause a whole host of problems. Many homeowners believe that buying a bigger furnace means better heating—after all, more power equals more heat, right? Not quite.
Furnace sizing is about matching the heating capacity, measured in British Thermal Units (BTUs), to your home's specific needs. Too big? The furnace will heat your home quickly but shut off too often—a problem known as short cycling. Too small? It won’t provide enough heat to keep your space comfortable, running constantly and wearing out prematurely.
Both cases mean higher energy bills, less comfort, and potentially costly repairs.
How HVAC Pros Size Your Furnace
Experts don’t guess—they use a detailed process called a Manual J load calculation. This calculation considers:
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Square footage of your home
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Insulation levels
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Window types and sizes
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Number of occupants
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Climate and outdoor temperatures
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Air infiltration and ductwork condition
The result? An accurate BTU range that matches your home’s actual heating demand.
What Happens If You Skip This Step?
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Oversized Furnace: Short cycles increase wear and tear, reduce efficiency, and create uneven room temperatures. Imagine your furnace turning on and off every few minutes—no good for comfort or your wallet.
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Undersized Furnace: Struggles to keep up with demand, running non-stop, which increases energy costs and causes early failure.
How to Avoid This Mistake
Always request a professional Manual J calculation from a licensed HVAC technician. Some companies may offer this service for free with a purchase.
🔗 Learn more about Manual J from the Air Conditioning Contractors of America (ACCA): Manual J Residential Load Calculation
Mistake #2: Ignoring AFUE Ratings and Efficiency
What Is AFUE?
AFUE stands for Annual Fuel Utilization Efficiency. It’s a percentage that tells you how much of the fuel your furnace burns is converted into heat for your home.
For example:
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An 80% AFUE furnace converts 80% of fuel energy into heat; 20% is lost through exhaust.
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A 96% AFUE furnace converts 96% of fuel energy; only 4% is lost.
The higher the AFUE, the more efficient your furnace, and the less you spend on fuel.
Why This Matters for Your Wallet
The difference between an 80% and 96% AFUE furnace might seem small, but over time it adds up significantly.
Let’s say your annual heating bill is $1,000:
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At 80% AFUE, about $200 worth of fuel is wasted.
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At 96% AFUE, only $40 is wasted.
Over a 15-year furnace lifespan, that’s a potential savings of $2,400 or more just from efficiency.
R-32 Refrigerant and High Efficiency
Many new high-efficiency furnaces are paired with advanced refrigerants like R-32, which have a lower global warming potential (GWP) and better heat transfer properties than older refrigerants. This helps systems run more efficiently and environmentally friendly.
You can find these cutting-edge systems in The Furnace Outlet’s R-32 gas furnace collection.
When to Prioritize High AFUE
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Colder Climates: You’ll use your furnace more, so efficiency saves you more.
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Long-Term Homeowners: The upfront cost pays off with fuel savings over time.
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Higher Utility Costs: If gas prices are high in your area, efficiency matters even more.
🔗 The EPA’s ENERGY STAR program offers detailed info on furnace efficiency: ENERGY STAR Furnaces
Mistake #3: Overlooking Venting Requirements and Installation Costs
Why Venting Matters
Not all furnaces vent the same way. Traditional 80% AFUE furnaces typically use metal vent pipes that expel gases through a chimney or side wall.
High-efficiency models (96%+ AFUE) often require PVC venting with special condensate drainage because these furnaces extract so much heat that exhaust gases condense into liquid water.
The Cost of Ignoring Installation Details
If you choose a high-efficiency furnace but don’t plan for the right venting and drainage, your installation can become complicated and costly.
Common pitfalls include:
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Underestimating labor costs
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Not factoring in vent pipe materials
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Failing to install proper condensate drainage
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Using unlicensed or inexperienced installers
This can lead to:
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Safety hazards like carbon monoxide leaks
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Voided warranties
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Increased risk of system failure
What to Do Instead
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Always hire a licensed, NATE-certified HVAC professional who understands local building codes and furnace venting requirements.
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Ask for a detailed installation quote upfront that includes venting and any modifications.
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Confirm the installer’s experience with R-32 compatible, high-efficiency furnaces.
Mistake #4: Skipping Maintenance and Warranty Details
Maintenance: Your Furnace’s Best Friend
You wouldn’t buy a car without planning for oil changes and tire rotations, right? Same with your furnace.
Regular maintenance:
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Keeps your system running efficiently
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Extends furnace lifespan
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Helps prevent breakdowns and costly repairs
What Maintenance Includes
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Changing or cleaning filters every 1-3 months
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Annual professional inspections and tune-ups
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Checking for gas leaks and proper venting
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Cleaning burners and heat exchangers
Warranty Fine Print: Don’t Get Caught Off Guard
Furnace warranties vary widely. Some cover parts only, some cover labor, and durations can range from 5 years to lifetime.
Tips:
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Read your warranty carefully before buying.
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Ask what voids your warranty (improper installation, lack of maintenance, etc.).
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Consider buying a service plan that includes annual maintenance to keep your warranty intact.
🔗 The Department of Energy provides helpful maintenance guidelines: DOE Heating System Maintenance
Mistake #5: Neglecting Rebates, Incentives, and Utility Programs
Why You Should Always Check for Rebates
Many local and federal programs incentivize upgrading to energy-efficient heating systems. These rebates can significantly reduce your upfront cost and shorten your payback period.
What’s Available?
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State and utility rebates for ENERGY STAR rated furnaces
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Tax credits for high-efficiency equipment
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Special financing or low-interest loans
How to Find Rebates Near You
Use the DSIRE database, the most comprehensive source for renewable energy and efficiency incentives in the U.S.
🔗 Check your eligibility here: DSIRE Incentives and Rebates
Don’t Miss Out!
Many homeowners skip this step and pay full price. Even a few hundred dollars can make a big difference on your final cost.
Jake’s Final Thoughts
Purchasing a new gas furnace can feel daunting, but it doesn’t have to be. Avoid these five common mistakes and you’ll be on track to selecting the right system for your home, your budget, and your comfort.
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Get the right size furnace for your home with a professional Manual J load calculation.
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Don’t skimp on efficiency—higher AFUE means lower bills.
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Plan for proper venting and professional installation to keep your family safe.
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Maintain your furnace regularly and understand your warranty terms.
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Check for rebates and incentives to save even more money.
If you’re ready to explore your options, The Furnace Outlet’s R-32 gas furnace collection offers some of the best high-efficiency, eco-friendly furnaces on the market today.
About Jake Lawson
Jake Lawson is a certified HVAC installer and industry veteran with 20+ years experience helping homeowners across the U.S. make smart heating and cooling decisions. Jake’s practical advice helps homeowners save money while staying comfortable and safe.
