Choosing a new air conditioning system or furnace can feel overwhelming. When you're looking to find the best HVAC system for your home, it's common to look for models with the highest efficiency ratings.
Surely the most efficient heating and cooling system provides the most comfort and lowest energy bills, right?
Not necessarily.
Efficiency ratings aren’t the only thing to think about when it comes to new air conditioner installation or installing a new furnace. Even though many focus only on efficiency ratings, proper HVAC system sizing is often even more important for your home's comfort and your energy bills.
Proper sizing has a major impact on humidity control and system longevity. The best HVAC system for your home balances efficiency and proper sizing.
In this guide, 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 recommending the best HVAC system for your home.
What Does a High SEER Rating Actually Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), indicates how effectively a cooling system cools your home over a normal cooling season. A SEER2 rating is the newer version of SEER, using testing methods that better represent real-world operating conditions. Most new air conditioners have a SEER2 rating, simply because that is the updated rating system for cooling equipment.
Fuel-burning heating system efficiency is measured by an AFUE rating, which stands for Annual Fuel Utilization Efficiency. Similar to cooling efficiency 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.
Even so, high ratings don't automatically guarantee lower utility bills. Real-world heating and air conditioner efficiency depends on several key factors, including the quality of the installation, the condition of your ductwork, insulation levels, thermostat settings and, most importantly, proper HVAC system sizing. Even the highest-efficiency system cannot deliver peak performance if it is bigger than necessary or smaller than needed for the home.
Why HVAC System Size Matters More Than You Think
Many assume a larger air conditioner or furnace will make their home the most comfortable or that they should just replace their old HVAC system with a same-sized replacement. The truth is, new heating system installation or AC replacement should be sized based on your home's actual heating and cooling needs—not just square footage or the capacity of the old system.
That's why reputable companies complete an HVAC load calculation, also called a Manual J calculation, before selecting replacement equipment. A Manual J calculation evaluates many details that impact your home's heating and cooling requirements, including:
- Total square footage
- Ceiling height
- Window size and placement
- Home insultation levels
- Air infiltration
- Area climate
- Household occupants
- Heat generated by appliances and lighting
- Ductwork condition
A properly sized air conditioner runs for enough time to cool your home consistently while eliminating excess humidity. That means more consistent temperatures, better indoor comfort and improved indoor humidity management. Proper sizing also helps the equipment to perform more effciently, reducing unnecessary wear that can reduce its service life or lead to frequent or expensive repairs.
When a furnace or AC is correctly sized, you get better comfort and more dependable performance.
Problems Caused by Oversized and Undersized Systems
Many homeowners are tempted to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. In reality, that’s rarely a good investment.
HVAC systems that are bigger than your home needs or too small can create comfort problems, increase utility costs and reduce efficiency regardless of their SEER rating.
Common Problems With Oversized HVAC Systems
An oversized air conditioner or heating system may heat or cool rapidly, but that doesn't mean it delivers the best comfort.
- Short cycling: An oversized HVAC system starts and stops often, reducing efficiency and increasing wear.
- High indoor humidity: Oversized air conditioners cool your home too quickly to remove excess moisture from the air.
- Uneven temperatures: Some rooms become too cold while others never feel comfortable.
- More wear and tear: Even though the system heats or cools your home fast, those frequent starts and stops can cause avoidable breakdowns due to the strain.
Cons Associated with Undersized HVAC Systems
An undersized HVAC system also can struggle:
- Long run times: The system operates almost continuously trying to reach the desired temperature, which also causes unnecessary wear and tear.
- Difficulty reaching thermostat settings: Your home may not feel comfortable during hot weather or feel too cool during winter.
- Greater energy usage: Running almost constantly can increase energy costs.
- Greater strain on very hot or cold days: HVAC systems that are too small can work harder in extreme temperatures, increasing wear and the chance of failure.
Balancing Efficiency and Size
When trying to decide between a high SEER vs right-sized system, remember that you don't automatically need the top-efficiency model on the market.
Often, a properly sized, mid-efficiency HVAC system will deliver better performance than an oversized premium system because it operates the way it was designed to.
Thebest choice is an energy-efficient HVAC system that's correctly sized for your home, your budget, your climate and your long-term goals.
When deciding 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 require a larger upfront investment than mid-range models but can lower long-term energy costs.
- Electricity rates: Areas with more expensive electricity may see greater long-term savings from higher-efficiency units.
- Seasonal weather conditions: It's essential your heating or cooling system has enough capacity to handle areas with extremely cold winters or intense summer heat.
- Time you plan to own the home: If you intend to remain 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
How does this work in a real world example?
Suppose there are two neighboring homes.
In the first, the homeowner chooses a premium high-efficiency HVAC system that's too big because the contractor only matched the previous unit. The other homeowner installs a right-sized, moderate-efficiency system after completing a Manual J calculation.
Although the second system has a lesser efficiency rating on paper, it may provide lower operating costs, better home comfort, improved humidity control and have a longer lifespan because it's appropriately sized to the home's needs.
Choose the Local HVAC Professional Who Designs the Right Solution
An HVAC replacement should involve more than selecting a system with the highest efficiency rating. The best system is one that meets your home’s heating and cooling requirements.
At Rapids Sheet Metal Works Inc, our experienced professionals perform an HVAC load calculation. Our team will evaluate your home's size and layout, your household's comfort needs and recommend equipment that's right for your home—not simply the biggest, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our team will help you identify any available rebates or tax incentives and provide information about HVAC financing options that make energy-efficient HVAC systems more accessible for all budgets.
Schedule an HVAC consultation online with Rapids Sheet Metal Works Inc now. Our team will evaluate your home, answer any questions and help you choose the properly sized high-efficiency system that keeps your family comfortable for many years.