Shopping for a new AC or furnace can feel overwhelming. When you're looking to find the best HVAC system for your home, it's understandable to focus on models with extremely high efficiency ratings.
Surely the most efficient equipment will provide the most comfort and lowest energy bills, right?
Not necessarily.
Efficiency ratings aren’t the only thing you should consider when it comes to new air conditioner installation or furnace replacement. Even though many focus only on energy efficiency, proper HVAC system sizing is equally, if not more important for your home's comfort and your power bills.
Proper sizing directly impacts humidity control and long-term reliability. The best HVAC system for your home balances energy efficiency and proper sizing.
In this guide, we'll explain what an air conditioner's SEER rating or SEER2 rating actually measures, why proper HVAC system sizing is so important and why qualified HVAC contractors 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), shows how effectively an air conditioner cools your home over a normal cooling season. A SEER2 rating is the newer 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 rating is the current rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by an AFUE rating, which stands for Annual Fuel Utilization Efficiency. Similar to 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 numbers don't by themselves guarantee lower utility bills. Actual heating and air conditioner efficiency depends on more than just efficiency ratings, including the way the system is installed, the quality of your ductwork, your home's insulation, thermostat settings and, most importantly, HVAC system sizing. Even the most efficient system cannot deliver peak performance if it is too large or too small for the home.
Why Correct HVAC System Sizing Matters More Than You Probably Think
Many assume a bigger air conditioner or furnace will make their home the most comfortable or that they should simply 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 selected based on your home's true 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 evaluates many factors that affect your home's comfort needs, including:
- Home square footage
- Ceiling height
- Window size and direction
- Insulation
- Air infiltration
- Local climate
- Household occupants
- Heat produced from appliances and lighting
- Ductwork condition
A properly sized air conditioner runs for enough time to cool your home consistently while removing excess humidity. That means more even temperatures, better indoor comfort and improved moisture control. This also allows the equipment to operate more effciently, reducing unnecessary wear that can reduce its service life or lead to costly breakdowns.
When a furnace or AC is correctly sized, you get improved comfort and more dependable performance.
Problems Caused by Oversized and Undersized HVAC Equipment
You may be tempted to buy the most energy efficient, biggest air conditioner or heating system on the market. However, that often isn't a good investment.
heating and cooling systems that are too large or too small can create indoor comfort challenges, 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 cycles repeatedly, reducing efficiency and increasing wear and tear.
- Humidity problems: Oversized air conditioners reach the set temperature too fast to remove excess moisture from the air.
- Inconsistent temperatures: Some rooms become too cold while others aren’t ever cool enough.
- Increased wear and tear: Even though the system reaches the target temperature rapidly, those constant cycles can cause avoidable breakdowns due to the strain.
Cons Associated with Undersized HVAC Systems
An undersized HVAC system can have the opposite problem:
- Continuous operation: The system stays on for extended 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 feel too cool during winter.
- Increased energy consumption: Running for extended periods can increase utility bills.
- Greater strain on very hot or cold days: HVAC systems that are too small can struggle in extreme temperatures, increasing component strain and the risk of breakdowns.
Why You Should Balance HVAC System Efficiency and Size
When trying to decide between a high SEER vs right-sized system, don't forget that you don't always need the highest-efficiency model on the market.
More often than not, a properly sized, mid-efficiency heating and cooling system will outperform an overly large premium system because it functions the way it was designed to.
Thesmartest choice is an energy-efficient HVAC system that's matched for your home, your budget, your climate and your long-term goals.
As you think about how to choose a new air conditioner or furnace, think about:
- Lower energy costs: Higher-efficiency and right-sized systems can reduce electricity use.
- Upfront investment: High-efficiency AC and heating systems often require a larger upfront investment than mid-range models but can lower long-term energy costs.
- Electricity rates: Areas with higher utility costs may see better long-term savings from higher-efficiency units.
- Climate: It's essential your heating or cooling system has enough capacity to handle areas with harsh winter weather or very hot summers.
- Time you plan to own the home: If you expect to live in your home for many years, the long-term energy savings of a higher-efficiency unit may justify the investment.
- Financial incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can offset the overall cost of qualifying equipment.
Real-World Example: High Seer vs. Right System Size
What does this look like in the real world?
Picture two neighboring homes.
At the first home, the homeowner chooses a premium high-efficiency HVAC system that's too big for the house because the contractor replaced it with the same size system as the previous unit. At the neighboring home, an HVAC professional installs a correctly 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 provide lower operating costs, better home comfort, more effective humidity control and have a longer lifespan because it's appropriately sized to the home's needs.
Work With an HVAC Professional Who Designs the Right Solution
Replacing your HVAC system should involve much more than selecting the unit with the highest efficiency rating. An ideal system is one that meets your heating and cooling requirements.
At Ilten's, our skilled HVAC experts 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 largest, most expensive unit or the one with the highest AFUE or SEER2 rating.
Our heating and cooling specialists will let you know about any available rebates or 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 Ilten's today. We'll gladly evaluate your home, answer any questions and help you choose the properly sized efficient system that keeps your family comfortable for many years.