Choosing a new AC or furnace can be stressful. If you're trying 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 equipment should deliver the most comfort and lowest energy bills, right?
It’s not quite that simple.
High efficiency isn't the only thing to think about when it comes to new air conditioner installation or furnace replacement. While many homeowners focus only on energy efficiency, proper HVAC system sizing is just as, if not more important for your home's comfort and your energy bills.
Proper sizing has a major impact on humidity control and long-term reliability. The best HVAC system for your home balances efficiency and proper sizing.
In this blog, 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 experienced HVAC professionals 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), shows how efficiently a cooling system cools your home over a typical cooling season. A SEER2 rating is the updated version of SEER, using testing methods that better reflect real-world operating conditions. Most 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 an AFUE rating, which is for Annual Fuel Utilization Efficiency. Like SEER and SEER2 ratings, 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.
That said, high ratings don't necessarily guarantee lower utility bills. Everyday 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 most efficient system cannot operate at its best if it is oversized or too small for the home.
Why HVAC System Size 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 simply replace their old HVAC system with a unit of the same capacity. In reality, 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 capacity of the old system.
That's why reputable technicians conduct an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation evaluates many variables that impact your home's comfort needs, including:
- Overall square footage
- Room height
- Window size and orientation
- Home insultation levels
- Air infiltration
- Regional climate
- Number of occupants
- Heat generated by appliances and lighting
- Air duct condition
A properly sized air conditioner runs through longer cooling cycles to cool your home evenly while removing excess humidity. That means more consistent temperatures, better indoor comfort and improved indoor humidity management. Proper sizing also helps the equipment to operate more effciently, reducing excessive wear and tear that can shorten its lifespan or lead to costly breakdowns.
When a furnace or AC is correctly sized, you get better comfort and more dependable performance.
Problems with Oversized and Undersized Heating and Cooling Systems
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 good investment.
HVAC systems that are bigger than necessary or smaller than your home requires can create indoor comfort challenges, 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 reach the thermostat setting fast, but that doesn't mean it delivers the best comfort.
- Short cycling: An oversized HVAC system starts and stops often, reducing efficiency and increasing equipment strain.
- 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.
- 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 also can struggle:
- Continuous operation: The system runs for long periods trying to reach the thermostat setting, which also causes additional wear.
- Difficulty maintaining the desired temperature: Your home may never feel as cool as you want during hot weather or always feel chilly in the winter.
- Higher energy use: 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 component strain and the chance of failure.
Balancing Efficiency and Size
When trying to decide between a high SEER vs right-sized system, don't forget that you don't necessarily need the most efficient model on the market.
More often than not, a professionally 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 properly sized for your home, your budget, your climate and your long-term needs.
When deciding how to choose a new air conditioner or furnace, consider:
- Energy savings: Higher-efficiency and right-sized systems can decrease electricity use.
- Initial cost: 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 electricity rates may see better 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.
- How long you'll own the home: 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.
- Available rebates or tax incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can reduce the overall cost of higher-efficiency systems.
Real-World Situation: High Seer vs. Right System Size
How does this play out in the real world?
Imagine two neighboring homes.
In one, the homeowner chooses a premium high-efficiency HVAC system that's too big because the contractor replaced it with the same size system as the previous unit. The other homeowner installs a correctly sized, moderate-efficiency system after completing a Manual J calculation.
While 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 last longer because it's properly matched to the home's needs.
Choose the HVAC Professional Who Designs Personalized Solutions
An HVAC replacement should involve more than selecting a model with the highest efficiency rating. The best system is one that meets your household heating and cooling requirements.
At H&C Heating and Cooling, our knowledgeable technicians perform an HVAC load calculation. We'll carefully evaluate your home's design, your household's comfort goals and recommend equipment that's designed specifically for your home—not simply the largest, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our heating and cooling specialists will connect you with any available tax rebates and provide information about HVAC financing options that make energy-efficient HVAC systems more accessible for all budgets.
Schedule an HVAC consultation online with H&C Heating and Cooling today. We'll evaluate your home, answer any questions and help you choose the properly sized energy-efficient system that keeps your family comfortable for years to come.