👋 Hey folks — Jake Lawson Here
Let me shoot straight with you. Picking the right 5-ton AC and furnace combo is one of the most important home investments you’ll ever make. Get it right, and you’ll enjoy years of affordable, comfortable heating and cooling. Get it wrong, and you might end up with higher energy bills, expensive repair calls, or even a system that doesn’t keep up with your home’s needs.
That’s why I want to highlight some of the most common — and most costly — buying mistakes I see homeowners make all too often. Trust me: a bit of careful planning up front can save you years of frustration.
Let’s jump into the big pitfalls you want to sidestep.
❌ Mistake #1: Oversizing or Undersizing the System
This one’s at the top of my list because I see it all the time. Bigger isn’t better — and smaller definitely isn’t cheaper if it doesn’t do the job.
Why It’s a Mistake:
Oversizing an AC and furnace combo will cause short cycling (frequent on/off), higher utility bills, more wear and tear, and terrible humidity control. Undersizing means your system will run non-stop and struggle to hit the temperature you set.
How to Avoid It:
Get a proper load calculation — often called a Manual J — done by a pro. This takes into account your home’s size, insulation, windows, and other factors. You can read more about why correct sizing matters at the ACCA’s Manual J standards page.
❌ Mistake #2: Ignoring Efficiency Ratings
That upfront price tag can be tempting — but if you buy purely on cost and ignore efficiency ratings like SEER2 and AFUE, you’re losing money every single month.
Why It’s a Mistake:
A lower-SEER2 AC and lower-AFUE furnace might cost less at the outset but will draw more electricity and gas year after year. It’s the classic “penny-wise, pound-foolish” decision.
How to Avoid It:
Prioritize systems with high SEER2 and AFUE ratings — ideally SEER2 14.5+ for the AC and AFUE 95%+ for the furnace. Check the U.S. Department of Energy EnergySaver guide for an overview of SEER2, and use that to make an informed decision.
❌ Mistake #3: Forgetting About Ductwork
No matter how good your new 5-ton combo is, if your ductwork is leaky or too small, you’re going to waste energy and leave rooms unevenly heated or cooled.
Why It’s a Mistake:
Poor duct design leads to insufficient airflow, increased dust, noisy operation, and higher utility bills.
How to Avoid It:
Have your ducts inspected — and if they’re undersized, damaged, or leaking, repair or replace them before installing your new combo. The EPA’s guide on duct sealing is a good place to brush up on best practices.
❌ Mistake #4: Going Cheap on Installation
A bargain installation might feel good initially, but a poorly installed system is going to cost you a lot more in the long run.
Why It’s a Mistake:
Your new combo depends on proper refrigerant charge, electrical connections, flue venting, and startup checks. Cut-rate installers often rush or skip key steps — leading to equipment failures or voiding your warranty.
How to Avoid It:
Work with a licensed, experienced contractor who follows all manufacturer guidelines. Many pro installers offer a labor warranty alongside the manufacturer’s part warranty.
❌ Mistake #5: Ignoring Refrigerant Type
More and more, R-32 refrigerant is becoming the go-to option due to its higher efficiency and lower global warming potential.
Why It’s a Mistake:
Older refrigerants like R-410A may be phased out and become more expensive to service over the years. Choosing R-32 means you’ll be future-ready, and you’ll probably gain a few points in system efficiency too.
How to Avoid It:
Always look for R-32 systems — especially when you want to future-proof your home. Check out the overview of R-32 refrigerant at ACHR News to learn what makes it such a game-changer.
❌ Mistake #6: Missing Rebates and Incentives
There are often utility company rebates and tax credits you could qualify for — especially if you pick a high-efficiency 5-ton combo.
Why It’s a Mistake:
Passing on these incentives could mean missing out on hundreds (sometimes thousands) of dollars in savings.
How to Avoid It:
Always check the DSIRE Database of State Incentives before you buy to see what rebates and tax credits are available for your zip code.
❌ Mistake #7: Getting Hung Up on Brand Alone
Brand loyalty can be good — but not at the expense of making a smart choice for your home.
Why It’s a Mistake:
Every major HVAC manufacturer has different series and product lines. Going for a famous name might mean you miss a model that’s a better fit for your specific situation.
How to Avoid It:
Look at features, efficiency ratings, and warranties first. Brands matter, but a well-matched system matters more.
❌ Mistake #8: Waiting Too Long to Replace
If your existing system is over 12–15 years old and starting to fail, it’s often smarter to plan your replacement before it breaks.
Why It’s a Mistake:
When your AC or furnace breaks mid-season, you’ll face long wait times for service and probably end up paying a premium for emergency replacement.
How to Avoid It:
Start shopping for a replacement before you’re desperate. This gives you time to shop smart — and catch any deals at reputable retailers like The Furnace Outlet’s R-32 5-ton collection — instead of making a rushed decision.
❌ Mistake #9: Not Asking the Right Questions
It might seem obvious, but don’t be shy — you deserve straight answers about your HVAC purchase.
Why It’s a Mistake:
If you don’t understand the scope of the install, the warranties, or even the rebate process, you could wind up disappointed after the fact.
How to Avoid It:
Have a list of questions prepared before signing anything. Ask about labor warranties, refrigerant handling certifications, the install process, and who you’ll call if you need service.
🎯 Conclusion — Jake’s Final Words
Avoiding these mistakes will put you in a much better position when buying a 5-ton AC and furnace combo. Focus on proper sizing, high-efficiency ratings, good ductwork, and a top-notch pro install. Be sure you pick a future-proof refrigerant like R-32, and don’t leave money on the table when it comes to rebates.
When you take your time and do your homework, you’ll end up with a system that keeps you and your family comfortable — without draining your wallet — for years to come.
And remember, your home’s HVAC setup is an investment in your daily comfort. Plan smart, shop smart, and you’ll be set for the long haul. 💪
