Choosing a new air conditioner or furnace can be stressful. If you're trying to find the best HVAC system for your home, it's common to look for models with the highest efficiency ratings.
Surely the most efficient system provides the most comfort and lowest energy bills, right?
It’s not quite that simple.
Energy efficiency isn't the only thing that matters when it comes to new air conditioner installation or furnace replacement. Even though many focus only on efficiency ratings, proper HVAC system sizing is equally, if not more important for your home's comfort and your energy bills.
Proper sizing also influences humidity control and long-term reliability. The best HVAC system for your home delivers efficiency and proper sizing.
In this article, 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.
What Does a High SEER Rating Actually Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), shows how effectively a cooling system 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. Today’s 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 measured by an AFUE rating, which is short for Annual Fuel Utilization Efficiency. As with SEER and SEER2 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 automatically 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, how much insulation your home has, thermostat settings and, most importantly, HVAC system sizing. Even the highest-efficiency system cannot perform as intended if it is too large or smaller than needed for the home.
Why Correct HVAC System Sizing Matters More Than Most Homeowners Realize
Many assume a bigger air conditioner or furnace will make their home the most comfortable or that they should simply replace their old HVAC system with a new one the same size. In reality, new heating system installation or air conditioner replacement should be sized 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 technicians perform an HVAC load calculation, also called a Manual J calculation, before selecting replacement equipment. A Manual J calculation analyzes many variables that impact your home's heating and cooling load, including:
- Overall square footage
- Room height
- Window size and placement
- Insulation
- Air leakage
- Local 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 evenly while pulling out excess humidity. That means steadier temperatures, better indoor comfort and improved moisture control. Proper sizing also helps the equipment to operate more effciently, reducing excessive wear and tear that can cause it to wear it out sooner or lead to more repairs and higher repair costs.
When a furnace or AC is the right size for your home, you get better comfort and more reliable operation.
Problems with Oversized and Undersized Systems
You may be tempted to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. The truth is, that's usually not a good investment.
HVAC systems that are bigger than necessary or undersized can create indoor comfort challenges, increase operating costs and reduce efficiency regardless of their SEER rating.
Common Problems With Oversized HVAC Systems
An oversized air conditioner or heating system may work quickly, but that doesn't mean it delivers the best comfort.
- 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 aren’t ever cool enough.
- More wear and tear: Even though the system works quickly, those repeated on-and-off cycles can cause avoidable breakdowns due to the strain.
Drawbacks of Undersized HVAC Systems
An undersized HVAC system can have the opposite problem:
- Long run times: The system runs for long periods trying to reach the set temperature, which also causes additional wear.
- Trouble reaching the thermostat setting: Your home may never feel as cool as you want during hot weather or feel too cool during winter.
- Higher energy use: Running nonstop can increase energy costs.
- Added strain during extreme weather: HVAC systems that are too small can struggle in extreme temperatures, increasing equipment wear and the risk of breakdowns.
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 properly sized, mid-efficiency heating and cooling system will provide better results than an overly large premium system because it runs the way it was designed to.
Thesmartest choice is an energy-efficient HVAC system that's properly sized 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 reduce electricity use.
- Purchase price: High-efficiency AC and heating systems often have a higher purchase price than mid-range models but can reduce long-term energy costs.
- Local utility costs: Areas with higher utility costs may see greater long-term savings from higher-efficiency units.
- Your local climate: It's crucial your heating or cooling system has the right capacity to handle areas with extremely cold winters or intense summer heat.
- Time you plan to 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 be worth the investment.
- Rebates and tax credits: Manufacturer promotions, {utility|equipment rebates and tax credits can offset the overall cost of higher-efficiency systems.
Real-World Example: High Seer vs. Right System Size
How does this work in a real world scenario?
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 simply matched the previous unit. Next door, the second homeowner installs a correctly sized, mid-efficiency system after completing a Manual J calculation.
Although the second system has a more modest 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 HVAC Professional Who Designs the Right Solution
HVAC replacent or installation should involve more than selecting a model with the highest efficiency rating. An ideal system is one that meets your heating and cooling requirements.
At Home Comfort Heating & Air, our skilled HVAC experts perform an HVAC load calculation. Our team will evaluate your home's size and layout, your household's comfort goals and recommend equipment that's right for your home—not simply the highest-capacity, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our team 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 Home Comfort Heating & Air to get started. We'll evaluate your home, answer your questions and help you choose the properly sized high-efficiency system that keeps your family comfortable for years to come.
