How We Right-Size Your Furnace With Real Load Calculations and Ductwork Checks

Picture this. Your old furnace quits on the coldest night of the year and you rush to replace it with the same size you had before. It seems simple, but that choice can leave you with rooms that never feel right, noisy airflow, and higher utility bills. The truth is, your next furnace probably should not be the same size as the one you have now.

At Forquer Heating & Air Conditioning, we see this all the time. Many older systems were installed without a formal load calculation, and equipment capacities and blower motor speeds have changed a lot over the last 20 years. When you call us for a furnace replacement, we do not just match the old nameplate. We engineer the right solution for your home.

Our Process: Accurate Sizing First, Smart Airflow Second

Step 1: Formal Load Calculation for Your Home

Square footage alone does not size a furnace. We complete a full load calculation that accounts for:

Window type and condition, how much heat they keep in or let out
Insulation location, type, and thickness in walls and ceilings
Construction details and layout that affect heat loss
Special conditions like additions or a finished basement

This gives us the ideal furnace capacity for your home, not a guess. It is the foundation for comfort and efficiency.

Step 2: Can Your Ductwork Handle It

After sizing the furnace, we verify that your existing ductwork can move the air that the system requires. We use a Ductulator and measure:

Trunk and branch sizes
Takeoffs and returns
The return air drop and other key connection points

Our goal is to avoid major ductwork modifications whenever possible. In 99 percent of homes we can improve airflow with targeted adjustments, which helps keep costs under control, especially when ducts run through finished spaces.

Step 3: Common Airflow Improvements We Recommend

If we find restrictions, we focus on high-impact fixes that are practical and cost-effective:

Replace an undersized return air drop. This is the vertical section where air comes back to the furnace. It is often too narrow. A wider drop lets more air reach the blower.
Add a sheet metal return air box under the furnace. This plenum improves airflow at the base of the unit. On systems 3 tons and above, we install this box by default because it prevents common airflow issues.
Fine-tune other connections and transitions to reduce noise and improve comfort.

For reference, many homes around 2,000 square feet land near a 3 ton drive, but the only way to know for sure is to calculate the load and check the ducts.

Why Right-Sizing and Airflow Matter

Comfort in every room. Correct capacity and proper ductwork keep temperatures even and reduce hot and cold spots.
Efficiency you can feel. A right-sized furnace runs steadier and wastes less energy, which helps lower bills.
Longer equipment life. When airflow is correct, the furnace and blower motor do not have to overwork.
Quieter operation. Adequate return air and smooth transitions cut down on whistling and rumbling.
Better air quality. Balanced airflow improves filtration and circulation throughout the home.

What You Can Do Before We Visit

Make note of rooms that are too hot or too cold during winter.
Share any details about your windows and insulation if you know them.
Do not assume your existing furnace size is correct.
Schedule an in-home assessment so we can measure, calculate, and design the right solution.

Why Homeowners Trust Forquer

We take the time to do it right. Led by Jim Forquer, our team brings decades of local experience to every furnace replacement. We perform a formal load calculation, evaluate your ductwork with a Ductulator, and recommend only the upgrades that deliver real results. Most homes do not need extensive ductwork changes, and when small improvements like a wider return air drop or a return air box will solve the problem, we tell you up front.

Key Takeaways

The best replacement furnace is rarely the same size as your old one.
A formal load calculation and a ductwork capacity check are nonnegotiable.
Simple fixes like a larger return air drop or a return air box can make a big difference.
Systems 3 tons and above always get a return air box from us to protect airflow and comfort.

Ready for a Furnace That Fits Your Home

If you are considering a furnace replacement, let us size it correctly and make sure your ductwork can support it. Contact Forquer Heating & Air Conditioning to schedule your in-home load calculation and airflow evaluation. We will design the right system for your home and your comfort, start to finish.