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.
After all, the most efficient equipment should deliver the most comfort and lowest energy bills, right?
Not necessarily.
High efficiency isn't the only thing that matters when it comes to new air conditioner installation or replacing your furnace. Although many people focus only on efficiency ratings, proper HVAC system sizing is often even 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 combines efficiency and proper sizing.
In this blog, we'll explain what an air conditioner's SEER rating or SEER2 rating actually measures, why correct HVAC size is so important and why experienced HVAC professionals 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 an AC cools your home over a standard cooling season. A SEER2 rating is the newer version of SEER, using testing methods that better simulate real-world operating conditions. Today’s new air conditioners have a SEER2 designation, simply because this rating is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is evaluated by AFUE, which stands for Annual Fuel Utilization Efficiency. Like SEER and SEER2, 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.
That said, high numbers don't necessarily guarantee lower utility bills. Everyday 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 most efficient system cannot operate at its best if it is bigger than necessary or too small for the home.
Why HVAC System Size Matters More Than You Probably Think
Many assume a larger air conditioner or furnace will make their home the most comfortable or that they should simply replace their old HVAC system with a same-sized replacement. The truth is, new heating system installation or a new air conditioner should be sized based on your home's true heating and cooling needs—not just square footage or the size of the previous unit.
That's why reputable contractors conduct an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation analyzes many details that affect your home's comfort needs, 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
- Air duct condition
A properly sized air conditioner runs for enough time to cool your home evenly while removing excess humidity. That means more consistent temperatures, better indoor comfort and improved moisture control. This also allows the equipment to perform more effciently, reducing strain that can cause it to wear it out sooner or lead to costly breakdowns.
When a furnace or AC is correctly sized, you get better comfort and long-lasting performance.
Problems Caused by Oversized and Undersized Systems
Many homeowners are tempted to buy the most energy efficient, largest-capacity air conditioner or heating system on the market. The truth is, that’s rarely a good investment.
HVAC systems that are bigger than your home needs or too small can create comfort problems, 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 reach the thermostat setting fast, but that doesn't mean it works well.
- Short cycling: An oversized HVAC system starts and stops often, reducing efficiency and increasing wear and tear.
- Poor humidity removal: Oversized air conditioners cool your home too quickly to remove indoor humidity from the air.
- Uneven temperatures: 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.
Drawbacks of Undersized HVAC Systems
An undersized HVAC system can have the opposite problem:
- Continuous operation: The system stays on for extended periods trying to reach the thermostat setting, which also causes extra strain.
- Difficulty reaching thermostat settings: Your home may not feel comfortable during hot weather or always feel chilly in the winter.
- Increased energy consumption: Running for extended periods can increase energy costs.
- Greater strain on very hot or cold days: HVAC systems that are too small can struggle in extreme temperatures, increasing equipment 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 properly sized, mid-efficiency heating and cooling system will outperform an oversized premium system because it runs the way it was designed to.
Thesmartest choice is an energy-efficient HVAC system that's matched for your home, your budget, your climate and your future plans.
As you think about how to choose a new air conditioner or furnace, consider:
- Efficiency savings: Higher-efficiency and right-sized systems can lower electricity use.
- Upfront investment: High-efficiency AC and heating systems often have a higher purchase price than mid-range models but can help reduce long-term energy costs.
- Electricity rates: Areas with higher electricity rates may see greater long-term savings from higher-efficiency units.
- Your local climate: It's essential your heating or cooling system has the right capacity to handle areas with harsh winter weather or intense summer heat.
- Length of home ownership: If you intend to remain 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 offset the overall cost of high-efficiency HVAC equipment.
Real-World Comparison: High Seer vs. Right System Size
How does this play out in the real world?
Suppose there are two neighboring homes.
At the first home, the homeowner chooses a premium high-efficiency HVAC system has far more capacity than the home needs because the contractor simply matched the previous unit. Next door, the second homeowner installs a properly 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, more effective humidity control and have a longer lifespan because it's correctly matched to the home's needs.
Work With an HVAC Professional Who Designs the Right Solution
Replacing your HVAC system should involve more than selecting a system with the top efficiency rating. The right system is one that meets your household heating and cooling requirements.
At Mountain Air, our knowledgeable technicians perform an HVAC load calculation. We'll evaluate your home's layout and construction, your household's comfort goals and recommend equipment that's right for your home—not simply the highest-capacity, latest and greatest unit or the one with the highest AFUE or SEER2 rating.
Our heating and cooling specialists will help you identify 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 Mountain Air now. 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.