Shopping for a new AC or furnace can feel overwhelming. When you're looking to find the best HVAC system for your home, it's understandable to focus on models with extremely high efficiency ratings.
Surely the most efficient system should deliver the most comfort and lowest energy bills, right?
It’s not quite that simple.
Efficiency ratings aren’t the only thing that matters when it comes to new air conditioner installation or furnace replacement. Even though many focus only on efficiency ratings, proper HVAC system sizing is equally, if not more important for your home's comfort and your power bills.
Proper sizing also influences humidity control and lasting performance. The best HVAC system for your home delivers energy efficiency and correct 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 helping you choose the best HVAC system for your home.
What Does it Mean if an AC Has a High SEER Rating?
A SEER rating, (Seasonal Energy Efficiency Ratio), measures how efficiently a cooling system cools your home over a normal cooling season. A SEER2 rating is the current version of SEER, using testing methods that better reflect real-world operating conditions. Most new air conditioners have a SEER2 designation, simply because this is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is measured by an AFUE rating, which stands for Annual Fuel Utilization Efficiency. As with cooling efficiency ratings, higher AFUE ratings indicate a high-efficiency HVAC system that uses less electricity to heat your home than lower-rated systems under standardized laboratory testing.
That said, high numbers don't by themselves guarantee lower utility bills. Actual heating and air conditioner efficiency depends on several key factors, including the quality of the installation, the condition of your ductwork, how much insulation your home has, thermostat settings and, most importantly, system sizing. Even the most efficient system cannot deliver peak performance if it is too large or smaller than needed for the home.
Why Proper HVAC Sizing Matters More Than You Probably Think
Many assume a higher-capacity air conditioner or furnace will heat or cool a home better or that they should just replace their old HVAC system with a new one the same size. In reality, new heating system installation or AC replacement should be chosen based on your home's actual heating and cooling needs—not just square footage or the size of the previous unit.
That's why reputable contractors perform an HVAC load calculation, also called a Manual J calculation, before selecting replacement equipment. A Manual J calculation analyzes many factors that impact your home's comfort needs, including:
- Home square footage
- Ceiling height
- Window size and direction
- Home insultation levels
- Air leakage
- Local climate
- Number of occupants
- Heat generated by appliances and lighting
- Ductwork condition
A properly sized air conditioner runs through longer cooling cycles to cool your home more uniformly while removing excess humidity. That means more even temperatures, better indoor comfort and improved indoor humidity management. It also helps the equipment to run more effciently, reducing unnecessary wear that can reduce its service life or lead to costly breakdowns.
When your heating or cooling system is correctly sized, you get greater comfort and long-lasting performance.
Problems with Oversized and Undersized Heating and Cooling Systems
Many homeowners are tempted to buy the most energy efficient, biggest air conditioner or heating system on the market. The truth is, that’s rarely a great idea.
HVAC systems that are bigger than necessary or smaller than your home requires can create indoor comfort challenges, increase operating 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 performs efficiently.
- Short cycling: An oversized HVAC system starts and stops often, reducing efficiency and increasing wear.
- Reduced humidity control: Oversized air conditioners finish cooling cycles too soon to remove excess moisture from the air.
- Inconsistent temperatures: Some rooms get too cold while others aren’t ever cool enough.
- More wear and tear: Even though the system reaches the target temperature rapidly, those frequent starts and stops can cause avoidable breakdowns due to the strain.
Drawbacks of Undersized HVAC Systems
An undersized HVAC system also can struggle:
- Long run times: The system operates almost continuously trying to reach the set temperature, which also causes unnecessary wear and tear.
- Trouble reaching the thermostat setting: Your home may not feel comfortable during hot weather or always feel chilly in the winter.
- Higher energy use: Running nonstop can increase energy costs.
- Extra stress during severe weather: HVAC systems that are too small can struggle in extreme temperatures, increasing component strain and the likelihood of repairs.
Why You Should Balance HVAC System Efficiency and Size
When trying to decide between a high SEER vs right-sized system, remember that you don't automatically need the highest-efficiency model on the market.
Often, a professionally sized, mid-efficiency heating and cooling system will outperform an overly large premium system because it operates the way it was designed to.
Theideal choice is an energy-efficient HVAC system that's correctly sized for your home, your budget, your climate and your future plans.
When deciding how to choose a new air conditioner or furnace, consider:
- Energy savings: Higher-efficiency and right-sized systems can reduce electricity use.
- Upfront investment: High-efficiency AC and heating systems often require a larger upfront investment than mid-range models but can help reduce long-term energy costs.
- Electricity rates: Areas with higher utility costs may see better long-term savings from higher-efficiency units.
- Your local climate: It's essential your heating or cooling system has adequate capacity to handle areas with extremely cold winters or extremely hot summers.
- Length of home ownership: If you plan to stay in your home for many years, the long-term energy savings of a higher-efficiency unit may be worth the investment.
- Rebates and tax credits: Manufacturer promotions, {utility|equipment rebates and tax credits can offset the overall cost of higher-efficiency systems.
Real-World Example: High Seer vs. Right System Size
How does this play out in a real world scenario?
Suppose there are two neighboring homes.
In the first, the homeowner chooses a premium high-efficiency HVAC system that's too big for the house because the contractor simply matched the previous unit. The other homeowner installs a correctly sized, mid-efficiency system after completing a Manual J calculation.
Even though the second system has a more modest efficiency rating on paper, it may provide lower operating costs, better home comfort, more effective humidity control and have a longer lifespan because it's properly matched to the home's needs.
Work With an HVAC Professional Who Designs Solutions Tailored to Your Home
An HVAC replacement should involve more than selecting a model with the top efficiency rating. The best system is one that meets your heating and cooling requirements.
At Better Air, our skilled HVAC experts perform an HVAC load calculation. We'll carefully evaluate your home's layout and construction, your household's comfort goals and recommend equipment that's designed specifically for your home—not simply the biggest, most expensive unit or the one with the highest AFUE or SEER2 rating.
Our team will help you identify any available tax rebates and provide information about HVAC financing options that make high-efficiency systems more accessible for all budgets.
Schedule an HVAC consultation online with Better Air to get started. Our team will evaluate your home, answer your questions and help you choose the right-sized efficient system that keeps your family comfortable for years to come.