Shopping for a new AC or furnace can be stressful. If you're trying to find the best HVAC system for your home, it's natural to look for models with extremely high efficiency ratings.
After all, the most efficient equipment provides the most comfort and lowest energy bills, right?
Not necessarily.
Energy efficiency isn't the only thing you should consider when it comes to new air conditioner installation or installing a new furnace. Even though many focus only on energy efficiency, proper HVAC system sizing is just as, if not more important for your home's comfort and your utility bills.
Proper sizing has a major impact on humidity control and lasting performance. The best HVAC system for your home delivers energy efficiency and proper sizing.
In this article, we'll explain what an air conditioner's SEER rating or SEER2 rating actually measures, why proper HVAC system size is so important and why trusted HVAC experts consider both when helping you choose the best HVAC system for your home.
What Does a High SEER Rating Actually Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), shows how efficiently an air conditioner cools your home over a typical cooling season. A SEER2 rating is the current version of SEER, using testing methods that better reflect real-world operating conditions. Nearly all new air conditioners have a SEER2 designation, simply because this is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by something called AFUE, which is for Annual Fuel Utilization Efficiency. Similar to SEER and SEER2 ratings, higher AFUE ratings indicate a high-efficiency HVAC system that uses less electricity to achieve indoor comfort than lower-rated systems under standardized laboratory testing.
However, high numbers don't necessarily guarantee lower utility bills. Everyday heating and air conditioner efficiency depends on several key factors, including the installation quality, the state of your ductwork, how much insulation your home has, thermostat settings and, most importantly, proper HVAC system sizing. Even the most efficient system cannot deliver peak performance if it is oversized or too small for the home.
Why Proper HVAC Sizing Matters More Than You Think
Many assume a higher-capacity air conditioner or furnace will heat or cool a home better or that they should simply replace their old HVAC system with a new one the same size. In reality, new heating system installation or air conditioner replacement should be sized based on your home's actual heating and cooling needs—not just square footage or the size of your existing equipment.
That's why reputable companies perform an HVAC load calculation, also called a Manual J calculation, before selecting replacement equipment. A Manual J calculation considers many factors that impact your home's heating and cooling requirements, including:
- Total square footage
- Ceiling height
- Window size and orientation
- Home insultation levels
- Air infiltration
- Area climate
- Number of occupants
- Heat produced from appliances and lighting
- Ductwork condition
A properly sized air conditioner runs through longer cooling cycles to cool your home evenly while removing excess humidity. That means steadier temperatures, better indoor comfort and improved humidity control. This also allows the equipment to run more effciently, reducing strain that can cause it to wear it out sooner or lead to more repairs and higher repair costs.
When your heating or cooling system is correctly sized, you get better comfort and long-lasting performance.
Problems Caused by Oversized and Undersized Systems
It might be tempting to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. The truth is, that's usually not a great idea.
HVAC systems that are too large or undersized can create indoor comfort challenges, increase utility costs and reduce efficiency regardless of their SEER rating.
Issues Created by Oversized HVAC Systems
An oversized air conditioner or heating system may work quickly, but that doesn't mean it delivers the best comfort.
- Short cycling: An oversized HVAC system turns on and off frequently, reducing efficiency and increasing wear.
- High indoor humidity: Oversized air conditioners finish cooling cycles too soon to remove excess moisture from the air.
- Hot and cold spots: Some rooms become too cold while others stay too warm.
- Additional equipment wear: Even though the system reaches the target temperature rapidly, those constant cycles can cause avoidable breakdowns due to the strain.
Drawbacks of Undersized HVAC Systems
An undersized HVAC system can have the opposite problem:
- Continuous operation: The system stays on for extended periods trying to reach the set temperature, which also causes extra strain.
- Difficulty reaching thermostat settings: Your home may feel cool enough during hot weather or always feel chilly in the winter.
- Higher energy use: Running for extended periods can increase utility bills.
- Greater strain on very hot or cold days: HVAC systems that are too small can struggle in extreme temperatures, increasing component strain and the likelihood of repairs.
Finding the Right Balance Between Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, remember that you don't automatically need the most efficient model on the market.
Often, a professionally sized, mid-efficiency heating and cooling system will deliver better performance than an overly large premium system because it operates the way it was designed to.
Theideal choice is an energy-efficient HVAC system that's matched for your home, your budget, your climate and your long-term needs.
As you think about how to choose a new air conditioner or furnace, keep these factors in mind:
- Energy savings: Higher-efficiency and right-sized systems can decrease electricity use.
- Initial cost: High-efficiency AC and heating systems often cost more initially than mid-range models but can lower long-term energy costs.
- Energy prices: Areas with more expensive electricity may see more significant long-term savings from higher-efficiency units.
- Climate: It's essential your heating or cooling system has enough capacity to handle areas with very cold winters or very hot summers.
- Length of home ownership: If you expect to live in your home for many years, the long-term energy savings of a higher-efficiency unit may offset the investment.
- Available rebates or tax incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can offset the overall cost of qualifying equipment.
Real-World Example: High Seer vs. Right System Size
What does this look like in the real world?
Suppose there are two neighboring homes.
In one, the homeowner chooses a premium high-efficiency HVAC system that's too big for the house because the contractor replaced it with the same size system as the previous unit. The other homeowner installs a right-sized, mid-efficiency system after completing a Manual J calculation.
Even though the second system has a lesser efficiency rating on paper, it may provide lower operating costs, better home comfort, improved humidity control and last longer because it's correctly matched to the home's needs.
Choose the HVAC Professional Who Designs the Right Solution
An HVAC replacement should involve more than selecting the unit with the top efficiency rating. An ideal system is one that meets your heating and cooling requirements.
At Pratt Brothers, our knowledgeable technicians perform an HVAC load calculation. Our team will evaluate your home's design, your household's comfort goals and recommend equipment that's properly matched for your home—not simply the largest, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our HVAC experts will help you identify any available tax rebates and provide information about HVAC financing options that make energy-efficient HVAC systems more accessible for all budgets.
Schedule an HVAC consultation online with Pratt Brothers now. We'll gladly evaluate your home, answer your questions and help you choose the correctly sized high-efficiency system that keeps your family comfortable for the long haul.