Shopping for a new AC or furnace can be stressful. When you're looking to find the best HVAC system for your home, it's understandable to look for models with the highest efficiency ratings.
Surely the most efficient heating and cooling system should deliver the most comfort and lowest energy bills, right?
Actually, that’s not always the case.
Energy efficiency isn't the only thing to think about when it comes to new air conditioner installation or furnace replacement. Although many people focus only on efficiency ratings, proper HVAC system sizing is just as, if not more important for your home's comfort and your power bills.
Proper sizing has a major impact on humidity control and long-term reliability. The best HVAC system for your home delivers energy efficiency and correct sizing.
In thisguide, 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 qualified HVAC contractors 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 efficiently a cooling system cools your home over a standard cooling season. A SEER2 rating is the updated version of SEER, using testing methods that better simulate real-world operating conditions. Today’s new air conditioners have a SEER2 rating, simply because this rating is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is evaluated by 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 heat your home than lower-rated systems under standardized laboratory testing.
That said, high numbers don't by themselves guarantee lower utility bills. Real-world heating and air conditioner efficiency depends on more than just efficiency ratings, including the installation quality, the quality of your ductwork, how much insulation your home has, thermostat settings and, most importantly, system sizing. Even the highest-efficiency system cannot deliver peak performance if it is oversized or undersized for the home.
Why Proper HVAC Sizing Matters More Than Most Homeowners Realize
Many assume a bigger air conditioner or furnace will work the best or that they should just replace their old HVAC system with a unit of the same capacity. In reality, new heating system installation or AC replacement should be selected 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 technicians perform an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation considers many factors that affect your home's heating and cooling requirements, including:
- Total square footage
- Ceiling height
- Window size and direction
- Home insultation levels
- Drafts and air leakage
- Area climate
- Household occupants
- Heat generated by appliances and lighting
- Air duct 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. This also allows the equipment to run more effciently, reducing excessive wear and tear that can cause it to wear it out sooner or lead to frequent or expensive repairs.
When a furnace or AC is properly sized, you get better comfort and long-lasting performance.
Problems Caused by Oversized and Undersized Systems
You may be tempted to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. In reality, that's usually not a smart choice.
heating and cooling systems that are bigger than necessary or too small can create indoor comfort challenges, increase utility costs and reduce efficiency regardless of their SEER rating.
Drawbacks of 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 wear.
- Poor humidity removal: Oversized air conditioners reach the set temperature too fast to remove excess moisture from the air.
- Inconsistent temperatures: Some rooms get 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 runs for long periods trying to reach the set temperature, which also causes additional wear.
- Trouble reaching the thermostat setting: Your home may not feel comfortable during hot weather or always feel chilly in the winter.
- Increased energy consumption: Running almost constantly can increase monthly energy expenses.
- Extra stress during severe weather: HVAC systems that are too small can work harder in extreme temperatures, increasing wear and the likelihood of repairs.
Balancing Efficiency and Size
When trying to decide between a high SEER vs right-sized system, don't forget that you don't necessarily need the highest-efficiency model on the market.
Often, a professionally sized, mid-efficiency HVAC system will outperform an oversized 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 long-term goals.
As you consider how to choose a new air conditioner or furnace, keep these factors in mind:
- Lower energy costs: Higher-efficiency and right-sized systems can lower electricity use.
- Purchase price: High-efficiency AC and heating systems often require a larger upfront investment than mid-range models but can lower long-term energy costs.
- Energy prices: 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 adequate capacity to handle areas with very cold winters or very hot summers.
- Time you plan to own the home: If you expect to live 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 reduce the overall cost of qualifying equipment.
Real-World Situation: High Seer vs. Right System Size
How does this work in the real world?
Imagine two neighboring homes.
At the first home, 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, moderate-efficiency system after completing a Manual J calculation.
While the second system has a more modest efficiency rating on paper, it may provide lower operating costs, better home comfort, improved humidity control and last longer because it's appropriately sized 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 system with the top efficiency rating. An ideal system is one that meets your household heating and cooling requirements.
At JTech Mechanical, 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 designed specifically for your home—not simply the biggest, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our HVAC experts will connect you with 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 JTech Mechanical today. We'll evaluate your home, answer any questions and help you choose the correctly sized high-efficiency system that keeps your family comfortable for years to come.