Choosing a new AC or furnace can be stressful. If you want to find the best HVAC system for your home, it's understandable to look for models with the highest efficiency ratings.
After all, the most efficient system should deliver the most comfort and lowest energy bills, right?
Actually, that’s not always the case.
High efficiency isn't the only thing you should consider when it comes to new air conditioner installation or replacing your furnace. Although many people focus only on energy efficiency, proper HVAC system sizing is just as, if not more important for your home's comfort and your utility bills.
Proper sizing also influences humidity control and lasting performance. The best HVAC system for your home delivers 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 qualified HVAC contractors 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), measures how efficiently an air conditioner cools your home over a typical cooling season. A SEER2 rating is the updated version of SEER, using test procedures that better represent real-world operating conditions. Nearly all new air conditioners have a SEER2 efficiency rating, simply because this rating is the current rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by AFUE, which is for Annual Fuel Utilization Efficiency. Similar to cooling efficiency ratings, 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 by themselves guarantee lower utility bills. Actual heating and air conditioner efficiency depends on more than just efficiency ratings, including the installation quality, the state of your ductwork, your home's insulation, thermostat settings and, most importantly, HVAC system sizing. Even the highest-efficiency system cannot deliver peak performance if it is oversized or too small for the home.
Why Correct HVAC System Sizing Matters More Than You Probably Think
Many assume a higher-capacity air conditioner or furnace will make their home the most comfortable or that they should just replace their old HVAC system with a unit of the same capacity. The truth is, new heating system installation or a new air conditioner should be selected 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 technicians complete an HVAC load calculation, also called a Manual J calculation, before selecting replacement equipment. A Manual J calculation evaluates many factors that impact your home's heating and cooling requirements, including:
- Total square footage
- Ceiling height
- Window size and direction
- Insulation
- Air infiltration
- Regional climate
- Household occupants
- Heat generated by appliances and lighting
- Ductwork condition
A properly sized air conditioner runs for enough time to cool your home more uniformly while eliminating excess humidity. That means more consistent temperatures, better indoor comfort and improved indoor humidity management. Proper sizing also helps the equipment to perform more effciently, reducing unnecessary wear that can reduce its service life or lead to more repairs and higher repair costs.
When a furnace or AC is correctly sized, you get greater comfort and more reliable operation.
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. The truth is, that’s rarely a great idea.
HVAC systems that are bigger than your home needs or too small can create comfort issues, increase utility 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 works well.
- Short cycling: An oversized HVAC system turns on and off frequently, reducing efficiency and increasing wear.
- Reduced humidity control: Oversized air conditioners finish cooling cycles too soon to remove enough moisture from the air.
- Hot and cold spots: Some rooms become too cold while others never feel comfortable.
- More wear and tear: Even though the system works quickly, those repeated on-and-off cycles can cause avoidable breakdowns due to the strain.
Drawbacks of Undersized HVAC Systems
An undersized HVAC system has a different set of problems:
- Continuous operation: The system runs for long periods trying to reach the desired temperature, which also causes unnecessary wear and tear.
- Difficulty maintaining the desired temperature: Your home may never feel as cool as you want during hot weather or feel too cool during winter.
- Increased energy consumption: Running for extended periods can increase monthly energy expenses.
- Greater strain on very hot or cold days: HVAC systems that are too small can struggle in extreme temperatures, increasing equipment 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, don't forget that you don't automatically need the most efficient model on the market.
In many cases, a professionally sized, mid-efficiency heating and cooling system will provide better results than an overly large premium system because it runs the way it was designed to.
Theideal choice is an energy-efficient HVAC system that's properly sized for your home, your budget, your climate and your long-term needs.
As you consider how to choose a new air conditioner or furnace, keep these factors in mind:
- Efficiency savings: Higher-efficiency and right-sized systems can decrease electricity use.
- Upfront investment: High-efficiency AC and heating systems often have a higher purchase price 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.
- Climate: It's essential your heating or cooling system has adequate capacity to handle areas with harsh winter weather or extremely 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 justify the investment.
- Rebates and tax credits: Manufacturer promotions, {utility|equipment rebates and tax credits can offset the overall cost of higher-efficiency systems.
Real-World Situation: High Seer vs. Right System Size
How does this play out in a real world example?
Picture 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. At the neighboring home, an HVAC professional 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 correctly matched to the home's needs.
Work With an HVAC Professional Who Designs the Right Solution
An HVAC replacement should involve more than selecting a model with the highest efficiency rating. The best system is one that meets your home’s heating and cooling requirements.
At County Line Mechanical LLC, our skilled HVAC experts perform an HVAC load calculation. We'll carefully evaluate your home's size and layout, your household's comfort goals and recommend equipment that's properly matched for your home—not simply the biggest, latest and greatest unit or the one with the highest AFUE or SEER2 rating.
Our heating and cooling specialists will let you know about any available rebates and 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 County Line Mechanical LLC today. 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 the long haul.