Shopping for a new air conditioning system or furnace can be intimidating. When you're looking to find the best HVAC system for your home, it's understandable to focus on models with extremely high efficiency ratings.
After all, 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. Although many people focus only on energy efficiency, proper HVAC system sizing is just as, if not more important for your home's comfort and your utility bills.
Proper sizing also influences humidity control and lasting performance. The best HVAC system for your home delivers 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 qualified HVAC contractors 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), indicates how effectively an air conditioner cools your home over a normal cooling season. A SEER2 rating is the updated version of SEER, using testing methods that better represent real-world operating conditions. Today’s 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 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.
Even so, high ratings 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, your home's insulation, thermostat settings and, most importantly, proper HVAC system sizing. Even the highest-rated system cannot perform as intended if it is too large or too small for the home.
Why HVAC System Size Matters More Than You Think
Many assume a bigger air conditioner or furnace will make their home the most comfortable or that they should just 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 true heating and cooling needs—not just square footage or the size of the previous unit.
That's why reputable contractors complete an HVAC load calculation, also called a Manual J calculation, before suggesting replacement equipment. A Manual J calculation evaluates many variables that affect your home's heating and cooling requirements, including:
- Overall square footage
- Ceiling height
- Window size and direction
- Home insultation levels
- Air infiltration
- Local climate
- Number of occupants
- Heat produced from appliances and lighting
- Air duct condition
A properly sized air conditioner runs through longer cooling cycles to cool your home more uniformly while removing excess humidity. That means more even temperatures, better indoor comfort and improved moisture control. It also helps the equipment to run more effciently, reducing strain that can cause it to wear it out sooner or lead to frequent or expensive repairs.
When HVAC equipment is correctly sized, you get greater comfort and long-lasting performance.
Problems with Oversized and Undersized Systems
It might be tempting to buy the most energy efficient, largest-capacity air conditioner or heating system on the market. However, that’s rarely a great idea.
heating and cooling systems that are bigger than necessary or undersized can create indoor comfort challenges, increase operating 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 performs efficiently.
- Short cycling: An oversized HVAC system starts and stops often, reducing efficiency and increasing equipment strain.
- High indoor humidity: Oversized air conditioners cool your home too quickly to remove excess moisture from the air.
- Inconsistent temperatures: Some rooms become too cold while others stay too warm.
- More wear and tear: 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 has a different set of problems:
- Long run times: The system operates almost continuously trying to reach the desired temperature, which also causes additional wear.
- Difficulty maintaining the desired temperature: Your home may never feel as cool as you want during hot weather or always feel chilly in the winter.
- Increased energy consumption: Running nonstop can increase energy costs.
- Added strain during extreme weather: HVAC systems that are too small can work harder in extreme temperatures, increasing component strain and the risk of breakdowns.
Finding the Right Balance Between 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.
More often than not, a correctly sized, mid-efficiency HVAC system will deliver better performance than an overly large premium system because it operates the way it was designed to.
Theideal 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 consider how to choose a new air conditioner or furnace, think about:
- Efficiency savings: Higher-efficiency and right-sized systems can decrease electricity use.
- Initial cost: High-efficiency AC and heating systems often require a larger upfront investment than mid-range models but can lower long-term energy costs.
- Electricity rates: 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 the right 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 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 Comparison: High Seer vs. Right System Size
What does this look like in a real world example?
Picture two neighboring homes.
At the first home, the homeowner chooses a premium high-efficiency HVAC system that's too big because the contractor only matched the previous unit. At the neighboring home, an HVAC professional installs a right-sized, moderate-efficiency 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, improved humidity control and have a longer lifespan because it's appropriately sized to the home's needs.
Choose the Local HVAC Professional Who Designs the Right Solution
HVAC replacent or installation should involve much more than selecting the unit with the highest efficiency rating. An ideal system is one that meets your heating and cooling requirements.
At Franklin's Heating & Air Conditioning, Inc, 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 properly matched for your home—not simply the largest, latest and greatest unit or the one with the highest AFUE or SEER2 rating.
Our team will let you know about 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 Franklin's Heating & Air Conditioning, Inc to get started. We'll evaluate your home, answer any questions and help you choose the properly sized efficient system that keeps your family comfortable for the long haul.