Shopping for a new air conditioner or furnace can feel overwhelming. If you want 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 heating and cooling system provides the most comfort and lowest energy bills, right?
Actually, that’s not always the case.
Energy efficiency isn't the only thing you should consider 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 utility bills.
Proper sizing has a major impact on humidity control and long-term reliability. The best HVAC system for your home delivers efficiency and correct 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 trusted HVAC experts consider both when recommending the best HVAC system for your home.
High Seer Ratings: What Do They Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), indicates how efficiently an AC cools your home over a normal cooling season. A SEER2 rating is the current version of SEER, using test procedures that better represent real-world operating conditions. Nearly all new air conditioners have a SEER2 efficiency rating, simply because this is the updated rating system for cooling equipment.
Fuel-burning heating system efficiency is measured by an AFUE rating, which stands for Annual Fuel Utilization Efficiency. Similar to 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 many factors, including the installation quality, the condition of your ductwork, insulation levels, thermostat settings and, most importantly, HVAC system sizing. Even the highest-rated system cannot deliver peak performance if it is too large or smaller than needed for the home.
Why Correct HVAC System Sizing 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 AC replacement should be sized based on your home's actual heating and cooling needs—not just square footage or the size of the previous unit.
That's why reputable companies perform an HVAC load calculation, also called a Manual J calculation, before suggesting 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 placement
- Home insultation levels
- Drafts and air leakage
- Regional climate
- Number of occupants
- Heat produced from appliances and lighting
- Air duct condition
A properly sized air conditioner runs long enough to cool your home more uniformly while eliminating excess humidity. That means more consistent temperatures, better indoor comfort and improved humidity control. This also allows the equipment to run more effciently, reducing strain that can shorten its lifespan or lead to costly breakdowns.
When HVAC equipment is properly sized, you get greater comfort and more dependable performance.
Problems with Oversized and Undersized Heating and Cooling Systems
Many homeowners are tempted to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. In reality, that's usually not a good investment.
heating and cooling systems that are too large or undersized can create indoor comfort challenges, 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 reach the thermostat setting fast, but that doesn't mean it performs efficiently.
- Short cycling: An oversized HVAC system turns on and off frequently, reducing efficiency and increasing wear and tear.
- Poor humidity removal: Oversized air conditioners cool your home too quickly to remove excess moisture from the air.
- Uneven temperatures: Some rooms become too cold while others never feel comfortable.
- Additional equipment wear: Even though the system heats or cools your home fast, those constant cycles can cause avoidable breakdowns due to the strain.
Issues Created by Undersized HVAC Systems
An undersized HVAC system can have the opposite problem:
- Continuous operation: The system operates almost continuously trying to reach the thermostat setting, which also causes extra strain.
- Difficulty maintaining the desired temperature: Your home may not feel comfortable during hot weather or feel too cool during winter.
- Greater energy usage: Running for extended periods can increase monthly energy expenses.
- Extra stress during severe weather: 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 most efficient model on the market.
More often than not, a professionally sized, mid-efficiency HVAC system will outperform an oversized 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 needs.
When deciding how to choose a new air conditioner or furnace, consider:
- Efficiency savings: Higher-efficiency and right-sized systems can decrease electricity use.
- Purchase price: 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 utility costs may see greater long-term savings from higher-efficiency units.
- Seasonal weather conditions: It's important your heating or cooling system has the right capacity to handle areas with extremely 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 justify the investment.
- Available rebates or tax incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can lower the overall cost of higher-efficiency systems.
Real-World Comparison: High Seer vs. Right System Size
How does this play out in a real world example?
Picture two neighboring homes.
In one, the homeowner chooses a premium high-efficiency HVAC system that's too big for the house because the contractor simply matched the previous unit. At the neighboring home, an HVAC professional installs a right-sized, moderate-efficiency system after completing a Manual J calculation.
While the second system has a lesser efficiency rating on paper, it may deliver lower operating costs, better home comfort, more effective humidity control and last longer because it's appropriately sized to the home's needs.
Work With an HVAC Professional Who Designs the Right Solution
An HVAC replacement should involve much more than selecting a model with the highest efficiency rating. An ideal system is one that meets your heating and cooling requirements.
At America's Green Heating & Air Conditioning, our knowledgeable technicians perform an HVAC load calculation. Our team will evaluate your home's design, your household's comfort goals and recommend equipment that's right for your home—not simply the biggest, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our team will let you know about any available tax rebates and provide information about HVAC financing options that make energy-efficient HVAC systems more accessible for all budgets.
Schedule an HVAC consultation online with America's Green Heating & Air Conditioning today. Our team will evaluate your home, answer any questions and help you choose the properly sized energy-efficient system that keeps your family comfortable for years to come.
