Shopping for a new air conditioner or furnace can be stressful. When you're looking to find the best HVAC system for your home, it's natural to focus on models with the highest efficiency ratings.
After all, the most efficient system should deliver the most comfort and lowest energy bills, right?
It’s not quite that simple.
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 efficiency ratings, proper HVAC system sizing is equally, if not more important for your home's comfort and your utility bills.
Proper sizing also influences humidity control and system longevity. The best HVAC system for your home combines energy efficiency and proper sizing.
In this guide, 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 select the best HVAC system for your home.
High Seer Ratings: What Do They Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), measures how effectively an air conditioner cools your home over a typical cooling season. A SEER2 rating is the current version of SEER, using testing methods that better represent real-world operating conditions. Today’s new air conditioners have a SEER2 rating, simply because that is the current rating system for cooling equipment.
Fuel-burning heating system efficiency is evaluated by something called AFUE, which is short for Annual Fuel Utilization Efficiency. Similar to cooling efficiency 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.
However, high numbers don't necessarily guarantee lower utility bills. Everyday heating and air conditioner efficiency depends on several key factors, including the installation quality, the state of your ductwork, insulation levels, thermostat settings and, most importantly, system sizing. Even the highest-rated system cannot deliver peak performance if it is bigger than necessary or too small for the home.
Why Correct HVAC System Sizing Matters More Than You Probably Think
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 unit of the same capacity. Actually, new heating system installation or a new air conditioner 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 contractors perform an HVAC load calculation, also called a Manual J calculation, before suggesting replacement equipment. A Manual J calculation evaluates many variables that affect your home's heating and cooling requirements, including:
- Home square footage
- Ceiling height
- Window size and orientation
- Home insultation levels
- Air infiltration
- Local climate
- Number of occupants
- Heat produced from appliances and lighting
- Ductwork condition
A properly sized air conditioner runs long enough to cool your home evenly while removing excess humidity. That means more even temperatures, better indoor comfort and improved humidity control. Proper sizing also helps the equipment to perform more effciently, reducing unnecessary wear that can cause it to wear it out sooner or lead to more repairs and higher repair costs.
When HVAC equipment is properly sized, you get better 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. In reality, that's usually not a good investment.
heating and cooling systems that are too large or smaller than your home requires 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 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 and tear.
- High indoor humidity: Oversized air conditioners cool your home too quickly to remove indoor humidity from the air.
- Inconsistent temperatures: Some rooms feel too cool while others stay too warm.
- More wear and tear: Even though the system heats or cools your home fast, those constant cycles can cause avoidable breakdowns due to the strain.
Cons Associated with Undersized HVAC Systems
An undersized HVAC system also can struggle:
- Continuous operation: The system stays on for extended periods trying to reach the thermostat setting, which also causes extra strain.
- Difficulty reaching thermostat settings: Your home may never feel as cool as you want during hot weather or feel too cool during winter.
- Greater energy usage: Running for extended periods can increase utility bills.
- Extra stress during severe weather: HVAC systems that are too small can run extremely hard in extreme temperatures, increasing equipment wear and the chance of failure.
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 necessarily need the most efficient model on the market.
In many cases, a correctly sized, mid-efficiency heating and cooling system will outperform an overly large premium system because it functions the way it was designed to.
Theideal choice is an energy-efficient HVAC system that's matched for your home, your budget, your climate and your future plans.
When deciding how to choose a new air conditioner or furnace, keep these factors in mind:
- Energy savings: Higher-efficiency and right-sized systems can lower electricity use.
- Upfront investment: High-efficiency AC and heating systems often cost more initially than mid-range models but can lower long-term energy costs.
- Electricity rates: Areas with higher electricity rates may see greater long-term savings from higher-efficiency units.
- Your local climate: It's important your heating or cooling system has enough 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
What does this look like in a real world example?
Imagine two neighboring homes.
At the first home, the homeowner chooses a premium high-efficiency HVAC system that's too big because the contractor only matched the previous unit. Next door, the second homeowner installs a properly sized, mid-SEER or AFUE system after completing a Manual J calculation.
Even though 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 last longer because it's properly matched to the home's needs.
Choose the Local HVAC Professional Who Designs the Right Solution
An HVAC replacement should involve more than selecting a system with the top efficiency rating. An ideal system is one that meets your heating and cooling requirements.
At Anderson Heating & A/C, our knowledgeable technicians perform an HVAC load calculation. We'll evaluate your home's size and layout, your household's comfort needs 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 heating and cooling specialists will help you identify any available rebates or tax incentives and provide information about HVAC financing options that make energy-efficient HVAC systems more accessible for all budgets.
Schedule an HVAC consultation online with Anderson Heating & A/C to get started. We'll gladly evaluate your home, answer your questions and help you choose the right-sized energy-efficient system that keeps your family comfortable for years to come.