Shopping for a new AC or furnace can be stressful. If you're trying 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 system will provide the most comfort and lowest energy bills, right?
It’s not quite that simple.
Efficiency ratings aren’t the only thing you should consider when it comes to new air conditioner installation or replacing your furnace. While many homeowners focus only on {energy efficiency|efficiency ratings, proper {HVAC system sizing is often even more important for your home's comfort and your power bills.
Proper sizing has a major impact on humidity control and long-term reliability. The best HVAC system for your home combines energy efficiency and correct sizing.
In thisguide, 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 helping you choose the best HVAC system for your home.
What Does a High SEER Rating Actually Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), shows how efficiently an AC cools your home over a standard cooling season. A SEER2 rating is the current version of SEER, using evaluation methods that better represent real-world operating conditions. Most new air conditioners have a SEER2 designation, simply because that is the updated rating system for cooling equipment.
Fuel-burning heating system efficiency is evaluated by AFUE, which stands for Annual Fuel Utilization Efficiency. As with SEER and SEER2, higher AFUE ratings indicate a high-efficiency HVAC system that uses less electricity to achieve indoor comfort than lower-rated systems under standardized laboratory testing.
However, high ratings don't automatically guarantee lower utility bills. Actual heating and air conditioner efficiency depends on several key factors, including the way the system is installed, the condition of your ductwork, your home's insulation, thermostat settings and, most importantly, proper HVAC system sizing. Even the highest-rated system cannot deliver peak performance if it is oversized or undersized for the home.
Why Proper HVAC Sizing Matters More Than Most Homeowners Realize
Many assume a bigger air conditioner or furnace will work the best or that they should just replace their old HVAC system with a new one the same size. The truth is, 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 size of your existing equipment.
That's why reputable contractors conduct an HVAC load calculation, also called a Manual J calculation, before selecting replacement equipment. A Manual J calculation considers many variables that impact your home's comfort needs, including:
- Home square footage
- Room height
- Window size and placement
- 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 for enough time to cool your home more uniformly while removing excess humidity. That means more even temperatures, better indoor comfort and improved humidity control. This also allows the equipment to perform more effciently, reducing excessive wear and tear that can reduce its service life or lead to more repairs and higher repair costs.
When HVAC equipment is properly sized, you get improved comfort and more reliable operation.
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. However, that’s rarely a great idea.
heating and cooling systems that are bigger than necessary 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 reach the thermostat setting fast, but that doesn't mean it performs efficiently.
- Short cycling: An oversized HVAC system starts and stops often, reducing efficiency and increasing equipment strain.
- Poor humidity removal: Oversized air conditioners reach the set temperature too fast to remove indoor humidity from the air.
- Uneven temperatures: Some rooms get too cold while others stay too warm.
- 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.
Drawbacks of Undersized HVAC Systems
An undersized HVAC system has a different set of problems:
- Long run times: The system runs for long periods trying to reach the set temperature, which also causes additional wear.
- Difficulty reaching thermostat settings: Your home may feel cool enough during hot weather or never feel warm enough in cold weather.
- Increased energy consumption: Running nonstop can increase utility bills.
- Added strain during extreme weather: HVAC systems that are too small can run extremely hard 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 automatically need the most efficient model on the market.
In many cases, a correctly sized, mid-efficiency heating and cooling system will provide better results than an oversized premium system because it operates 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.
When deciding how to choose a new air conditioner or furnace, consider:
- Lower energy costs: Higher-efficiency and right-sized systems can lower electricity use.
- Purchase price: High-efficiency AC and heating systems often have a higher purchase price than mid-range models but can help reduce long-term energy costs.
- Local utility costs: Areas with higher utility costs may see greater long-term savings from higher-efficiency units.
- Climate: It's essential your heating or cooling system has adequate capacity to handle areas with extremely 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 be worth the investment.
- Financial incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can reduce the overall cost of higher-efficiency systems.
Real-World Comparison: High Seer vs. Right System Size
How does this work in a real world example?
Imagine two neighboring homes.
At the first home, 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, mid-efficiency system after completing a Manual J calculation.
While the second system has a more modest efficiency rating on paper, it may deliver lower operating costs, better home comfort, more effective humidity control and have a longer lifespan because it's properly matched to the home's needs.
Choose the HVAC Professional Who Designs Solutions Tailored to Your Home
An HVAC replacement should involve more than selecting the unit 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 needs and recommend equipment that's right for your home—not simply the biggest, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our heating and cooling specialists will help you identify any available rebates and 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 Diedrick's Heating and Air Conditioning to get started. We'll gladly evaluate your home, answer your questions and help you choose the properly sized energy-efficient system that keeps your family comfortable for many years.