Shopping for a new air conditioner or furnace can be intimidating. If you're trying to find the best HVAC system for your home, it's natural to look for models with extremely high efficiency ratings.
After all, the most efficient equipment will provide the most comfort and lowest energy bills, right?
Not necessarily.
Efficiency ratings aren’t the only thing to think about when it comes to new air conditioner installation or installing a new furnace. Even though many focus only on energy efficiency, proper HVAC system sizing is just as, if not more important for your home's comfort and your power bills.
Proper sizing also influences humidity control and system longevity. The best HVAC system for your home balances energy efficiency and correct sizing.
In this guide, 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.
High Seer Ratings: What Do They Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), indicates how effectively a cooling system cools your home over a typical cooling season. A SEER2 rating is the current version of SEER, using test procedures that better represent real-world operating conditions. Most new air conditioners have a SEER2 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. Like SEER and SEER2 ratings, 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 ratings don't by themselves guarantee lower utility bills. Real-world heating and air conditioner efficiency depends on many factors, including the quality of the installation, the state of your ductwork, how much insulation your home has, thermostat settings and, most importantly, system sizing. Even the highest-rated system cannot deliver peak performance if it is bigger than necessary or smaller than needed for the home.
Why Correct HVAC System Sizing Matters More Than You Think
Many assume a higher-capacity air conditioner or furnace will heat or cool a home better or that they should simply replace their old HVAC system with a same-sized replacement. The truth is, new heating system installation or air conditioner replacement should be selected 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 contractors complete an HVAC load calculation, also called a Manual J calculation, before suggesting replacement equipment. A Manual J calculation considers many factors that impact your home's heating and cooling load, including:
- Total square footage
- Ceiling height
- Window size and direction
- Home insultation levels
- Air infiltration
- Regional climate
- Household occupants
- Heat generated by appliances and lighting
- Ductwork condition
A properly sized air conditioner runs through longer cooling cycles to cool your home consistently while pulling out excess humidity. That means more consistent temperatures, better indoor comfort and improved moisture control. This also allows the equipment to operate more effciently, reducing strain that can shorten its lifespan or lead to frequent or expensive repairs.
When your heating or cooling system is the right size for your home, you get greater comfort and more dependable performance.
Problems Caused by Oversized and Undersized Heating and Cooling Systems
Many homeowners are tempted to buy the most energy efficient, biggest air conditioner or heating system on the market. In reality, that's usually not a good investment.
HVAC systems that are bigger than necessary or undersized can create comfort problems, increase utility costs and reduce efficiency regardless of their SEER rating.
Drawbacks of Oversized HVAC Systems
An oversized air conditioner or heating system may heat or cool rapidly, but that doesn't mean it works well.
- Short cycling: An oversized HVAC system starts and stops often, reducing efficiency and increasing equipment strain.
- Humidity problems: Oversized air conditioners cool your home too quickly to remove enough moisture from the air.
- Uneven temperatures: Some rooms get too cold while others aren’t ever cool enough.
- More wear and tear: Even though the system heats or cools your home fast, those frequent starts and stops can cause avoidable breakdowns due to the strain.
Cons Associated with Undersized HVAC Systems
An undersized HVAC system can have the opposite problem:
- Long run times: 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.
- Increased energy consumption: Running nonstop can increase monthly energy expenses.
- Extra stress during severe weather: HVAC systems that are too small can work harder in extreme temperatures, increasing equipment wear and the likelihood of repairs.
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 always need the highest-efficiency model on the market.
More often than not, a properly sized, mid-efficiency HVAC 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.
When deciding how to choose a new air conditioner or furnace, think about:
- Energy savings: Higher-efficiency and right-sized systems can lower electricity use.
- Purchase price: High-efficiency AC and heating systems often cost more initially than mid-range models but can lower long-term energy costs.
- Local utility costs: Areas with higher electricity rates may see greater long-term savings from higher-efficiency units.
- Seasonal weather conditions: It's crucial your heating or cooling system has the right capacity to handle areas with extremely cold winters or very hot summers.
- Length of home ownership: 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.
- Rebates and tax credits: Manufacturer promotions, {utility|equipment rebates and tax credits can lower the overall cost of qualifying equipment.
Real-World Example: High Seer vs. Right System Size
What does this look like in a real world example?
Suppose there are two neighboring homes.
At the first home, the homeowner chooses a premium high-efficiency HVAC system that's too big because the contractor replaced it with the same size system as the previous unit. The other homeowner installs a properly sized, mid-SEER or AFUE system after completing a Manual J calculation.
While the second system has a lower efficiency rating on paper, it may provide lower operating costs, better home comfort, more effective humidity control and last longer because it's appropriately sized to the home's needs.
Choose the HVAC Professional Who Designs Personalized Solutions
An HVAC replacement should involve much more than selecting the unit with the top efficiency rating. The best system is one that meets your home’s heating and cooling requirements.
At Northwest Services, our knowledgeable technicians perform an HVAC load calculation. We'll evaluate your home's size and layout, your household's heating and cooling preferences and recommend equipment that's designed specifically for your home—not simply the biggest, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our HVAC experts will help you identify any available tax rebates and provide information about HVAC financing options that make high-efficiency systems more accessible for all budgets.
Schedule an HVAC consultation online with Northwest Services now. Our team will evaluate your home, answer any questions and help you choose the properly sized high-efficiency system that keeps your family comfortable for many years.