Choosing a new AC or furnace can feel overwhelming. If you want to find the best HVAC system for your home, it's common to look for models with extremely high efficiency ratings.
Surely the most efficient system provides the most comfort and lowest energy bills, right?
It’s not quite that simple.
High efficiency isn't the only thing to think about when it comes to new air conditioner installation or replacing your furnace. While many homeowners focus only on energy efficiency, proper HVAC system sizing is equally, if not more important for your home's comfort and your energy bills.
Proper sizing directly impacts humidity control and system longevity. The best HVAC system for your home combines energy efficiency and correct sizing.
In this blog, 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 recommending 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), shows how efficiently an AC cools your home over a typical cooling season. A SEER2 rating is the newer version of SEER, using evaluation methods that better simulate real-world operating conditions. Nearly all new air conditioners have a SEER2 efficiency rating, simply because this rating is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is evaluated by an AFUE rating, which is for Annual Fuel Utilization Efficiency. Similar to SEER and SEER2, 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.
That said, high ratings don't automatically guarantee lower utility bills. Real-world heating and air conditioner efficiency depends on many factors, including the installation quality, the state 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 bigger than necessary or undersized 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 new one the same size. Actually, new heating system installation or a new air conditioner should be chosen based on your home's actual heating and cooling needs—not just square footage or the capacity of the old system.
That's why reputable companies perform an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation analyzes many variables that impact your home's heating and cooling load, including:
- Total square footage
- Room height
- Window size and placement
- Home insultation levels
- Air leakage
- Local climate
- Household occupants
- Heat generated by 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 indoor humidity management. It also helps the equipment to operate more effciently, reducing excessive wear and tear that can shorten its lifespan or lead to costly breakdowns.
When your heating or cooling system is properly sized, you get improved comfort and more dependable performance.
Problems with Oversized and Undersized HVAC Equipment
It might be tempting to buy the most energy efficient, largest-capacity air conditioner or heating system on the market. The truth is, that's usually not a great idea.
HVAC systems that are too large or too small 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 heat or cool rapidly, but that doesn't mean it performs efficiently.
- Short cycling: An oversized HVAC system starts and stops often, reducing efficiency and increasing wear and tear.
- Poor humidity removal: Oversized air conditioners reach the set temperature too fast to remove enough moisture from the air.
- Uneven temperatures: Some rooms feel too cool while others aren’t ever cool enough.
- Increased wear and tear: Even though the system heats or cools your home fast, those constant cycles can cause avoidable breakdowns due to the strain.
Cons Associated with Undersized HVAC Systems
An undersized HVAC system also can struggle:
- Long run times: The system runs for long 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 feel too cool during winter.
- Greater energy usage: Running almost constantly can increase utility bills.
- Added strain during extreme weather: HVAC systems that are too small can work harder in extreme temperatures, increasing equipment wear and the chance of failure.
Finding the Right Balance Between Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, don't forget that you don't necessarily need the top-efficiency model on the market.
In many cases, a correctly sized, mid-efficiency heating and cooling system will outperform an oversized premium system because it operates the way it was designed to.
Thebest 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:
- Energy savings: Higher-efficiency and right-sized systems can reduce electricity use.
- Purchase price: High-efficiency AC and heating systems often require a larger upfront investment than mid-range models but can help reduce long-term energy costs.
- Energy prices: Areas with more expensive electricity may see greater long-term savings from higher-efficiency units.
- Climate: It's crucial your heating or cooling system has enough capacity to handle areas with extremely cold winters or intense summer heat.
- Length of home ownership: 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.
- Rebates and tax credits: Manufacturer promotions, {utility|equipment rebates and tax credits can lower the overall cost of high-efficiency HVAC equipment.
Real-World Example: High Seer vs. Right System Size
How does this play out in a real world example?
Imagine 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 only matched the previous unit. At the neighboring home, an HVAC professional installs a correctly sized, mid-efficiency system after completing a Manual J calculation.
Although the second system has a lower efficiency rating on paper, it may provide lower operating costs, better home comfort, improved humidity control and last longer because it's properly matched to the home's needs.
Choose the Local HVAC Professional Who Designs Solutions Tailored to Your Home
An HVAC replacement should involve more than selecting the unit with the top efficiency rating. An ideal system is one that meets your household heating and cooling requirements.
At Polar Air & Mechanical, our knowledgeable technicians 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 right for your home—not simply the largest, most expensive 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 efficient heating and cooling systems more accessible for all budgets.
Schedule an HVAC consultation online with Polar Air & Mechanical to get started. We'll evaluate your home, answer your questions and help you choose the correctly sized energy-efficient system that keeps your family comfortable for the long haul.
