Shopping for a new AC or furnace can feel overwhelming. If you want to find the best HVAC system for your home, it's natural to focus on models with extremely high efficiency ratings.
After all, the most efficient equipment should deliver the most comfort and lowest energy bills, right?
Not necessarily.
Energy efficiency isn't the only thing to think about when it comes to new air conditioner installation or furnace replacement. While many homeowners 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 combines energy efficiency and correct sizing.
In this blog, we'll explain what an air conditioner's SEER rating or SEER2 rating actually measures, why proper HVAC system sizing is so important and why trusted HVAC experts consider both when helping you select 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), indicates how efficiently a cooling system cools your home over a typical cooling season. A SEER2 rating is the current version of SEER, using evaluation methods that better represent real-world operating conditions. Nearly all new air conditioners have a SEER2 designation, simply because this is the current rating system for cooling equipment.
Fuel-burning heating system efficiency is evaluated by something called AFUE, which is 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.
That said, high ratings don't by themselves guarantee lower utility bills. Actual heating and air conditioner efficiency depends on more than just efficiency ratings, including the way the system is installed, the condition of your ductwork, how much insulation your home has, thermostat settings and, most importantly, system sizing. Even the highest-rated system cannot perform as intended if it is bigger than necessary 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 a new air conditioner should be chosen based on your home's true heating and cooling needs—not just square footage or the size of your existing equipment.
That's why reputable companies complete an HVAC load calculation, also called a Manual J calculation, before selecting 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 orientation
- Insulation
- Air infiltration
- Area climate
- Household 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 eliminating excess humidity. That means steadier temperatures, better indoor comfort and improved moisture control. Proper sizing also helps the equipment to perform more effciently, reducing unnecessary wear that can reduce its service life or lead to more repairs and higher repair costs.
When HVAC equipment is correctly sized, you get greater comfort and long-lasting performance.
Problems with Oversized and Undersized Systems
Many homeowners are tempted to buy the most energy efficient, biggest air conditioner or heating system on the market. In reality, that’s rarely a good investment.
HVAC systems that are bigger than necessary or too small 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 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.
- Humidity problems: Oversized air conditioners reach the set temperature too fast to remove excess moisture from the air.
- Uneven temperatures: Some rooms feel too cool while others aren’t ever cool enough.
- Additional equipment wear: Even though the system reaches the target temperature rapidly, those constant cycles 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.
- Trouble reaching the thermostat setting: Your home may feel cool enough during hot weather or always feel chilly in the winter.
- Higher energy use: Running nonstop can increase utility bills.
- Added strain during extreme weather: HVAC systems that are too small can struggle in extreme temperatures, increasing wear and the chance of failure.
Why You Should Balance HVAC System Efficiency and Size
When trying to decide between a high SEER vs right-sized system, keep in mind that you don't necessarily need the most efficient model on the market.
Often, a correctly sized, mid-efficiency HVAC system will outperform an oversized premium system because it operates the way it was designed to.
Thebest choice is an energy-efficient HVAC system that's properly sized 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 reduce electricity use.
- Initial cost: 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 electricity rates may see better long-term savings from higher-efficiency units.
- Climate: It's important your heating or cooling system has adequate capacity to handle areas with very cold winters or intense summer heat.
- How long you'll own the home: If you plan to stay in your home for many years, the long-term energy savings of a higher-efficiency unit may justify the investment.
- Available rebates or tax incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can reduce the overall cost of higher-efficiency systems.
Real-World Example: High Seer vs. Right System Size
How does this work in the real world?
Imagine two neighboring homes.
In one, the homeowner chooses a premium high-efficiency HVAC system has far more capacity than the home needs because the contractor only matched the previous unit. The other homeowner installs a correctly sized, mid-efficiency system after completing a Manual J calculation.
Although the second system has a more modest 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 the Right Solution
HVAC replacent or installation should involve more than selecting the unit with the highest efficiency rating. The best system is one that meets your home’s heating and cooling requirements.
At Miller Climate Control LLC, our skilled HVAC experts perform an HVAC load calculation. We'll 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 HVAC experts will help you identify any available rebates and tax incentives and provide information about HVAC financing options that make efficient heating and cooling systems more accessible for all budgets.
Schedule an HVAC consultation online with Miller Climate Control LLC now. We'll gladly evaluate your home, answer your questions and help you choose the properly sized high-efficiency system that keeps your family comfortable for years to come.
