Choosing a new air conditioner or furnace can be intimidating. 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.
Surely the most efficient heating and cooling system provides the most comfort and lowest energy bills, right?
It’s not quite that simple.
Efficiency ratings aren’t the only thing you should consider when it comes to new air conditioner installation or furnace replacement. While many homeowners focus only on energy efficiency, proper HVAC system sizing is equally, if not more important for your home's comfort and your utility bills.
Proper sizing also influences humidity control and long-term reliability. The best HVAC system for your home combines 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 experienced HVAC professionals consider both when recommending 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 effectively an air conditioner cools your home over a standard cooling season. A SEER2 rating is the newer version of SEER, using testing methods that better reflect real-world operating conditions. Today’s new air conditioners have a SEER2 designation, simply because that is the current rating system for cooling equipment.
Fuel-burning heating system efficiency is measured by an AFUE rating, which is short for Annual Fuel Utilization Efficiency. Like cooling efficiency ratings, higher AFUE ratings indicate a high-efficiency HVAC system that uses less electricity to keep you comfortable 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 way the system is installed, the quality of your ductwork, your home's insulation, thermostat settings and, most importantly, HVAC system sizing. Even the highest-rated system cannot perform as intended if it is too large or too small for the home.
Why Correct HVAC System Sizing Matters More Than You Think
Many assume a higher-capacity 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 selected 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 contractors perform an HVAC load calculation, also called a Manual J calculation, before suggesting replacement equipment. A Manual J calculation analyzes many variables that affect your home's heating and cooling load, including:
- Overall square footage
- Room height
- Window size and direction
- Insulation
- Drafts and air leakage
- Local climate
- Number of occupants
- Heat produced from appliances and lighting
- Ductwork condition
A properly sized air conditioner runs long enough to cool your home evenly while eliminating excess humidity. That means more consistent temperatures, better indoor comfort and improved humidity control. It also helps the equipment to operate more effciently, reducing strain that can reduce its service life or lead to more repairs and higher repair costs.
When your heating or cooling system is correctly sized, you get improved comfort and long-lasting performance.
Problems with Oversized and Undersized HVAC Equipment
You may be tempted to buy the most energy efficient, largest-capacity air conditioner or heating system on the market. The truth is, that's usually not a good investment.
heating and cooling systems that are bigger than necessary or smaller than your home requires can create comfort issues, increase energy expenses and reduce efficiency regardless of their SEER rating.
Common Problems With Oversized HVAC Systems
An oversized air conditioner or heating system may reach the thermostat setting fast, but that doesn't mean it delivers the best comfort.
- Short cycling: An oversized HVAC system cycles repeatedly, reducing efficiency and increasing equipment strain.
- Poor humidity removal: Oversized air conditioners finish cooling cycles too soon to remove enough moisture from the air.
- Hot and cold spots: Some rooms get too cold while others aren’t ever cool enough.
- Additional equipment wear: Even though the system works quickly, 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 stays on for extended periods trying to reach the desired temperature, which also causes additional wear.
- Trouble reaching the thermostat setting: Your home may never feel as cool as you want during hot weather or always feel chilly in the winter.
- Greater energy usage: Running nonstop can increase energy costs.
- Greater strain on very hot or cold days: HVAC systems that are too small can struggle in extreme temperatures, increasing component strain and the risk of breakdowns.
Balancing Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, remember that you don't always need the top-efficiency model on the market.
Often, a correctly sized, mid-efficiency heating and cooling system will outperform an oversized premium system because it runs 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 long-term goals.
As you think about how to choose a new air conditioner or furnace, consider:
- Energy savings: Higher-efficiency and right-sized systems can lower electricity use.
- Upfront investment: High-efficiency AC and heating systems often cost more initially than mid-range models but can lower long-term energy costs.
- Electricity rates: Areas with higher electricity rates may see more significant long-term savings from higher-efficiency units.
- Seasonal weather conditions: It's essential your heating or cooling system has the right capacity to handle areas with very 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 offset the investment.
- Available rebates or tax incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can reduce the overall cost of high-efficiency HVAC equipment.
Real-World Situation: High Seer vs. Right System Size
How does this work in the real world?
Picture 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 only matched the previous unit. The other homeowner installs a right-sized, mid-SEER or AFUE system after completing a Manual J calculation.
Although the second system has a lesser efficiency rating on paper, it may deliver lower operating costs, better home comfort, more effective humidity control and last longer because it's properly matched to the home's needs.
Choose the HVAC Professional Who Designs Solutions Tailored to Your Home
HVAC replacent or installation should involve much more than selecting the unit with the top efficiency rating. The best system is one that meets your home’s heating and cooling requirements.
At Air Current AC & Heat, our experienced professionals perform an HVAC load calculation. We'll carefully evaluate your home's size and layout, your household's comfort goals and recommend equipment that's properly matched for your home—not simply the highest-capacity, most expensive unit or the one with the highest AFUE or SEER2 rating.
Our HVAC experts will connect you with 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 Air Current AC & Heat today. Our team will evaluate your home, answer any questions and help you choose the right-sized energy-efficient system that keeps your family comfortable for years to come.