Shopping for a new air conditioner or furnace can feel overwhelming. When you're looking to find the best HVAC system for your home, it's understandable to look for models with the highest efficiency ratings.
Surely the most efficient equipment provides the most comfort and lowest energy bills, right?
Not necessarily.
Efficiency ratings aren’t the only thing that matters when it comes to new air conditioner installation or furnace replacement. While many homeowners focus only on efficiency ratings, proper HVAC system sizing is often even more important for your home's comfort and your power bills.
Proper sizing also influences humidity control and long-term reliability. The best HVAC system for your home balances energy efficiency and proper sizing.
In this blog, 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 trusted HVAC experts 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), measures how efficiently a cooling system cools your home over a typical cooling season. A SEER2 rating is the updated version of SEER, using test procedures that better represent real-world operating conditions. Today’s new air conditioners have a SEER2 designation, simply because this is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is measured by something called AFUE, which is short 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.
Even so, high numbers 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, system sizing. Even the highest-efficiency system cannot operate at its best if it is bigger than necessary or undersized for the home.
Why Correct HVAC System Sizing Matters More Than Most Homeowners Realize
Many assume a larger air conditioner or furnace will make their home the most comfortable or that they should simply replace their old HVAC system with a same-sized replacement. Actually, new heating system installation or air conditioner replacement should be sized based on your home's current heating and cooling needs—not just square footage or the capacity of the old system.
That's why reputable companies complete an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation evaluates many factors that affect your home's heating and cooling load, including:
- Home square footage
- Room height
- Window size and direction
- Home insultation levels
- Drafts and air leakage
- Regional climate
- Household occupants
- Heat produced from appliances and lighting
- Ductwork condition
A properly sized air conditioner runs long enough to cool your home evenly while pulling out excess humidity. That means more even temperatures, better indoor comfort and improved moisture control. This also allows the equipment to perform more effciently, reducing strain that can reduce its service life or lead to frequent or expensive repairs.
When your heating or cooling system is correctly sized, you get better comfort and more reliable operation.
Problems Caused by Oversized and Undersized Heating and Cooling Systems
You may be tempted to buy the most energy efficient, biggest air conditioner or heating system on the market. In reality, that’s rarely a smart choice.
HVAC systems that are bigger than your home needs or undersized 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 work quickly, but that doesn't mean it performs efficiently.
- Short cycling: An oversized HVAC system cycles repeatedly, reducing efficiency and increasing equipment strain.
- Reduced humidity control: Oversized air conditioners reach the set temperature too fast to remove enough moisture from the air.
- Uneven temperatures: Some rooms get too cold while others never feel comfortable.
- More wear and tear: Even though the system reaches the target temperature rapidly, those frequent starts and stops 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 runs for long periods trying to reach the desired temperature, which also causes additional wear.
- Difficulty reaching thermostat settings: Your home may feel cool enough during hot weather or always feel chilly in the winter.
- Higher energy use: 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 wear and the risk of breakdowns.
Why You Should Balance HVAC System Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, don't forget that you don't always need the top-efficiency model on the market.
More often than not, a professionally sized, mid-efficiency HVAC system will deliver better performance than an oversized premium system because it runs the way it was designed to.
Theideal 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, consider:
- Energy savings: Higher-efficiency and right-sized systems can lower electricity use.
- Upfront investment: 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 better 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 very cold winters or intense summer heat.
- Length of home ownership: If you intend to remain in your home for many years, the long-term energy savings of a higher-efficiency unit may offset the investment.
- Rebates and tax credits: Manufacturer promotions, {utility|equipment rebates and tax credits can reduce the overall cost of higher-efficiency systems.
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 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 more modest efficiency rating on paper, it may provide lower operating costs, better home comfort, improved humidity control and last longer because it's appropriately sized to the home's needs.
Choose the Local HVAC Professional Who Designs Personalized Solutions
Replacing your HVAC system should involve more than selecting a system with the top efficiency rating. The best system is one that meets your heating and cooling requirements.
At PS Cool Heat, our knowledgeable technicians perform an HVAC load calculation. We'll carefully evaluate your home's size and layout, your household's heating and cooling preferences and recommend equipment that's right for your home—not simply the largest, latest and greatest unit or the one with the highest AFUE or SEER2 rating.
Our HVAC experts will let you know about any available rebates and tax incentives and provide information about HVAC financing options that make high-efficiency systems more accessible for all budgets.
Schedule an HVAC consultation online with PS Cool Heat today. Our team will 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.
