Choosing a new air conditioner or furnace can be stressful. If you're trying to find the best HVAC system for your home, it's understandable to focus on models with the highest efficiency ratings.
Surely the most efficient system will provide 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 replacing your furnace. Even though many 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 directly impacts humidity control and system longevity. The best HVAC system for your home balances energy 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 sizing is so important and why qualified HVAC contractors consider both when helping you select the best HVAC system for your home.
High Seer Ratings: What Do They Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), indicates how effectively an AC cools your home over a normal cooling season. A SEER2 rating is the current version of SEER, using test procedures that better simulate real-world operating conditions. Nearly all new air conditioners have a SEER2 designation, simply because that is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by AFUE, which is short for Annual Fuel Utilization Efficiency. Like SEER and SEER2 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.
Even so, high numbers don't automatically guarantee lower utility bills. Real-world heating and air conditioner efficiency depends on many 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-rated system cannot perform as intended if it is oversized or too small for the home.
Why HVAC System Size Matters More Than You Probably Think
Many assume a bigger air conditioner or furnace will heat or cool a home better or that they should simply replace their old HVAC system with a unit of the same capacity. In reality, new heating system installation or air conditioner replacement should be chosen based on your home's current heating and cooling needs—not just square footage or the size of the previous unit.
That's why reputable technicians conduct an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation considers many details that affect your home's heating and cooling requirements, including:
- Total square footage
- Ceiling height
- Window size and orientation
- Insulation
- Drafts and air leakage
- Area climate
- Household occupants
- Heat produced from appliances and lighting
- Ductwork condition
A properly sized air conditioner runs for enough time to cool your home more uniformly while eliminating excess humidity. That means more consistent temperatures, better indoor comfort and improved moisture control. It also helps the equipment to perform more effciently, reducing unnecessary wear that can reduce its service life or lead to costly breakdowns.
When your heating or cooling system is properly sized, you get greater comfort and long-lasting performance.
Problems with Oversized and Undersized HVAC Equipment
It might be tempting to buy the most energy efficient, biggest air conditioner or heating system on the market. The truth is, that often isn't a good investment.
HVAC systems that are bigger than your home needs or undersized can create comfort problems, increase operating costs and reduce efficiency regardless of their SEER rating.
Drawbacks of 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 cycles repeatedly, reducing efficiency and increasing equipment strain.
- Poor humidity removal: Oversized air conditioners finish cooling cycles too soon to remove indoor humidity from the air.
- Hot and cold spots: Some rooms feel too cool while others stay too warm.
- Additional equipment wear: 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 has a different set of problems:
- Continuous operation: The system runs for long periods trying to reach the thermostat setting, which also causes unnecessary wear and tear.
- Difficulty maintaining the desired temperature: Your home may not feel comfortable during hot weather or never feel warm enough in cold weather.
- Increased energy consumption: Running almost constantly can increase utility bills.
- Greater strain on very hot or cold days: 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 automatically need the top-efficiency model on the market.
Often, a correctly sized, mid-efficiency heating and cooling system will provide better results than an overly large premium system because it runs 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, think about:
- Efficiency 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 reduce long-term energy costs.
- Energy prices: Areas with higher utility costs may see greater long-term savings from higher-efficiency units.
- Your local climate: It's important your heating or cooling system has adequate capacity to handle areas with very cold winters or very hot summers.
- How long you'll 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.
- Available rebates or tax incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can lower the overall cost of high-efficiency HVAC equipment.
Real-World Situation: High Seer vs. Right System Size
What does this look like in a real world scenario?
Picture two neighboring homes.
In the first, the homeowner chooses a premium high-efficiency HVAC system has far more capacity than the home needs because the contractor replaced it with the same size system as the previous unit. The other homeowner installs a correctly sized, moderate-efficiency system after completing a Manual J calculation.
Although 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 correctly matched to the home's needs.
Work With an HVAC Professional Who Designs the Right Solution
An HVAC replacement should involve 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 Evenaire Heating & Air Conditioning, our experienced professionals perform an HVAC load calculation. Our team will evaluate your home's layout and construction, your household's comfort goals and recommend equipment that's properly matched for your home—not simply the largest, latest and greatest unit or the one with the highest AFUE or SEER2 rating.
Our HVAC experts will let you know about any available rebates or tax incentives and provide information about HVAC financing options that make high-efficiency systems more accessible for all budgets.
Schedule an HVAC consultation online with Evenaire Heating & Air Conditioning to get started. Our team will evaluate your home, answer any questions and help you choose the correctly sized efficient system that keeps your family comfortable for the long haul.
