Choosing a new air conditioner or furnace can be intimidating. If you want to find the best HVAC system for your home, it's understandable to focus on models with the highest efficiency ratings.
After all, the most efficient equipment provides 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 replacing your 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 also influences humidity control and lasting performance. The best HVAC system for your home delivers 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 size 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), measures how efficiently an air conditioner cools your home over a typical cooling season. A SEER2 rating is the current version of SEER, using test procedures that better reflect real-world operating conditions. Nearly all new air conditioners have a SEER2 efficiency rating, simply because this is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by AFUE, which is for Annual Fuel Utilization Efficiency. Like 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.
Even so, high numbers don't necessarily guarantee lower utility bills. Real-world heating and air conditioner efficiency depends on more than just efficiency ratings, including the way the system is installed, the condition 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 too small for the home.
Why Proper HVAC 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. Actually, new heating system installation or AC replacement should be sized based on your home's current heating and cooling needs—not just square footage or the size of the previous unit.
That's why reputable contractors 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 heating and cooling load, including:
- Total square footage
- Ceiling height
- Window size and direction
- Insulation
- Drafts and air leakage
- Local climate
- Household occupants
- Heat generated by appliances and lighting
- Air duct condition
A properly sized air conditioner runs long enough to cool your home more uniformly while eliminating excess humidity. That means more even temperatures, better indoor comfort and improved humidity control. This also allows the equipment to run more effciently, reducing unnecessary wear that can cause it to wear it out sooner or lead to more repairs and higher repair costs.
When your heating or cooling system is properly sized, you get greater comfort and long-lasting performance.
Problems Caused by Oversized and Undersized HVAC Equipment
Many homeowners are tempted to buy the most energy efficient, largest-capacity air conditioner or heating system on the market. In reality, that often isn't a great idea.
heating and cooling systems that are bigger than your home needs or undersized can create comfort problems, 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 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 wear and tear.
- Poor humidity removal: Oversized air conditioners finish cooling cycles too soon to remove enough moisture from the air.
- Uneven temperatures: Some rooms feel too cool while others aren’t ever cool enough.
- Additional equipment wear: Even though the system reaches the target temperature rapidly, those repeated on-and-off cycles 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 stays on for extended periods trying to reach the thermostat setting, which also causes additional wear.
- Difficulty maintaining the desired temperature: Your home may not feel comfortable during hot weather or always feel chilly in the winter.
- Greater energy usage: Running almost constantly can increase energy costs.
- Greater strain on very hot or cold days: HVAC systems that are too small can work harder in extreme temperatures, increasing wear and the chance of failure.
Finding the Right Balance Between Efficiency and Size
When trying to decide between a high SEER vs right-sized system, remember that you don't automatically need the most efficient model on the market.
In many cases, a properly sized, mid-efficiency heating and cooling system will provide better results than an oversized premium system because it functions the way it was designed to.
Thesmartest choice is an energy-efficient HVAC system that's correctly 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 lower electricity use.
- Initial cost: High-efficiency AC and heating systems often require a larger upfront investment than mid-range models but can lower long-term energy costs.
- Local utility costs: Areas with higher utility costs may see better long-term savings from higher-efficiency units.
- Your local climate: It's essential your heating or cooling system has enough capacity to handle areas with harsh winter weather 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 qualifying equipment.
Real-World Comparison: High Seer vs. Right System Size
How does this play out in a real world example?
Suppose there are two neighboring homes.
In one, the homeowner chooses a premium high-efficiency HVAC system has far more capacity than the home needs because the contractor replaced it with the same size system as the previous unit. Next door, the second homeowner installs a correctly sized, moderate-efficiency system after completing a Manual J calculation.
Although the second system has a lower efficiency rating on paper, it may deliver lower operating costs, better home comfort, improved humidity control and last longer because it's properly matched to the home's needs.
Choose the HVAC Professional Who Designs the Right Solution
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 Diedrick's Heating and Air Conditioning, our knowledgeable technicians perform an HVAC load calculation. Our team will evaluate your home's design, your household's comfort goals and recommend equipment that's right for your home—not simply the highest-capacity, latest and greatest 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 high-efficiency systems more accessible for all budgets.
Schedule an HVAC consultation online with Diedrick's Heating and Air Conditioning today. We'll evaluate your home, answer your questions and help you choose the right-sized efficient system that keeps your family comfortable for the long haul.