Choosing a new air conditioner or furnace can feel overwhelming. When you're looking to find the best HVAC system for your home, it's natural to focus on models with extremely high efficiency ratings.
After all, the most efficient equipment will provide the most comfort and lowest energy bills, right?
Actually, that’s not always the case.
Efficiency ratings aren’t the only thing that matters when it comes to new air conditioner installation or installing a new furnace. While many homeowners focus only on efficiency ratings, proper HVAC system sizing is equally, if not more important for your home's comfort and your power bills.
Proper sizing has a major impact on humidity control and system longevity. The best HVAC system for your home balances efficiency and correct sizing.
In this guide, we'll explain what an air conditioner's SEER rating or SEER2 rating actually measures, why correct HVAC size is so important and why qualified HVAC contractors consider both when helping you choose the best HVAC system for your home.
What Does a High SEER Rating Actually Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), measures how effectively a cooling system cools your home over a standard cooling season. A SEER2 rating is the newer version of SEER, using testing methods that better reflect real-world operating conditions. Nearly all new air conditioners have a SEER2 designation, simply because that is the updated rating system for cooling equipment.
Fuel-burning heating system efficiency is evaluated by AFUE, which is for Annual Fuel Utilization Efficiency. As with 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.
However, high ratings don't by themselves guarantee lower utility bills. Everyday heating and air conditioner efficiency depends on many factors, including the quality of the installation, the quality of your ductwork, your home's insulation, thermostat settings and, most importantly, system sizing. Even the highest-efficiency system cannot deliver peak performance if it is bigger than necessary or too small for the home.
Why Correct HVAC System Sizing Matters More Than Most Homeowners Realize
Many assume a bigger air conditioner or furnace will heat or cool a home better or that they should just replace their old HVAC system with a same-sized replacement. Actually, new heating system installation or a new air conditioner 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 companies perform an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation considers many details that impact your home's comfort needs, including:
- Total square footage
- Room height
- Window size and placement
- Home insultation levels
- Air infiltration
- Area climate
- Number of occupants
- Heat generated by appliances and lighting
- Ductwork condition
A properly sized air conditioner runs long enough to cool your home more uniformly while removing excess humidity. That means steadier temperatures, better indoor comfort and improved moisture control. Proper sizing also helps the equipment to perform more effciently, reducing excessive wear and tear that can reduce its service life or lead to more repairs and higher repair costs.
When a furnace or AC is correctly sized, you get better comfort and more dependable performance.
Problems Caused by Oversized and Undersized Heating and Cooling Systems
It might be tempting to buy the most energy efficient, biggest air conditioner or heating system on the market. The truth is, that's usually not a good investment.
heating and cooling systems that are too large or too small can create comfort problems, 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 starts and stops often, reducing efficiency and increasing wear.
- Poor humidity removal: Oversized air conditioners cool your home too quickly to remove indoor humidity from the air.
- Hot and cold spots: Some rooms feel too cool while others stay too warm.
- Increased wear and tear: Even though the system works quickly, those repeated on-and-off cycles can cause avoidable breakdowns due to the strain.
Issues Created by Undersized HVAC Systems
An undersized HVAC system has a different set of problems:
- Continuous operation: The system operates almost continuously trying to reach the desired temperature, which also causes extra strain.
- Difficulty maintaining the desired temperature: Your home may feel cool enough during hot weather or feel too cool during winter.
- Higher energy use: Running nonstop can increase monthly energy expenses.
- Extra stress during severe weather: HVAC systems that are too small can run extremely hard in extreme temperatures, increasing wear and the chance of failure.
Balancing Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, keep in mind that you don't automatically need the most efficient model on the market.
More often than not, a properly sized, mid-efficiency heating and cooling system will outperform an overly large premium system because it operates 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 future plans.
As you consider how to choose a new air conditioner or furnace, keep these factors in mind:
- Efficiency savings: Higher-efficiency and right-sized systems can reduce electricity use.
- Initial cost: High-efficiency AC and heating systems often have a higher purchase price than mid-range models but can lower long-term energy costs.
- Local utility costs: Areas with higher electricity rates may see more significant long-term savings from higher-efficiency units.
- Seasonal weather conditions: It's important your heating or cooling system has adequate capacity to handle areas with harsh winter weather or extremely hot summers.
- Time you plan to 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.
- Available rebates or tax incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can offset the overall cost of qualifying equipment.
Real-World Example: High Seer vs. Right System Size
What does this look like in a real world scenario?
Suppose there are two neighboring homes.
In the first, the homeowner chooses a premium high-efficiency HVAC system that's too big for the house 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, 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 Personalized Solutions
HVAC replacent or installation should involve more than selecting a model with the top efficiency rating. An ideal system is one that meets your household heating and cooling requirements.
At Air Temperature Control, our skilled HVAC experts perform an HVAC load calculation. We'll carefully evaluate your home's design, your household's comfort goals and recommend equipment that's designed specifically for your home—not simply the biggest, latest and greatest unit or the one with the highest AFUE or SEER2 rating.
Our team will connect you with any available rebates or tax incentives and provide information about HVAC financing options that make efficient heating and cooling systems more accessible for all budgets.
Schedule an HVAC consultation online with Air Temperature Control 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 many years.