News

By: Mitch Ross

In the fairy tale “Goldilocks and the Three Bears,” Goldilocks intrudes on the three bears’ home and samples porridge, looking for one that's not too hot, not too cold but just right. This simple story offers a perfect analogy for one of the most critical decisions in home heating, ventilation and air conditioning (HVAC) systems: proper sizing.

For homeowners, choosing an HVAC unit that’s the ideal fit can mean the difference between energy efficiency, comfort and unnecessary costs. An improperly sized system wastes electricity, causes maintenance issues and can lead to comfort issues in a home.

The System That’s Too Big

Let’s start with the “too big” scenario, akin to Papa Bear’s scalding porridge. An oversized HVAC unit might seem appealing (it cools or heats a home quickly), but it comes with significant drawbacks. These systems cycle on and off frequently in short bursts, known as short cycling. This inefficiency leads to uneven temperatures, with rooms feeling clammy because the unit doesn’t run long enough to properly dehumidify the air. 

In humid Arkansas, this often leads to discomfort and can even lead to mold growth in a home. Electrically, short cycling spikes energy consumption during startups, which causes units to use more energy overall. Moreover, the constant on-off stress accelerates wear and tear on components like compressors and fans, shortening the system’s lifespan and leading to costly repairs. In my experience, oversizing units is more the norm than the exception. Don’t have a “the bigger, the better” mentality when replacing your unit!

The System That’s Too Small

On the flip side, an undersized unit is like Mama Bear's chilly porridge — it’s never quite enough. These systems run almost continuously, struggling to reach the desired temperature, especially during extreme weather. Homeowners endure persistent discomfort, with hot or cold spots throughout the house. Energy-wise, this constant operation devours electricity without delivering results, causing bills to be 10-15% higher than a properly sized unit. Over time, the strain can cause premature failure of parts.

The System That’s Just Right

So, what makes a unit “just right,” like Baby Bear’s perfect bowl? Proper sizing, typically determined by a professional load calculation using methods like Air Conditioning Contractors of America’s Manual J, accounts for factors such as home square footage, insulation, windows and local climate. A right-sized HVAC maintains consistent temperatures, effectively controls humidity and operates efficiently, reducing energy use by 20% or more compared to mismatches. This translates to lower electric bills, extended equipment life (often 15-20 years) and higher comfort.

In today’s era of rising energy costs, skipping proper sizing is a missed opportunity. Homeowners should consult certified HVAC professionals for accurate assessments. Like Goldilocks, settling for “just right” ensures a comfortable, cost-effective home.

Mitch Ross is the energy efficiency manager for the Electric Cooperatives of Arkansas.