Shopping for a new AC or furnace can be intimidating. If you're trying to find the best HVAC system for your home, it's understandable to focus on models with extremely high efficiency ratings.
After all, the most efficient heating and cooling system should deliver the most comfort and lowest energy bills, right?
Actually, that’s not always the case.
Energy efficiency isn't the only thing you should consider when it comes to new air conditioner installation or installing a new furnace. While many homeowners focus only on efficiency ratings, proper HVAC system sizing is equally, if not 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 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 qualified HVAC contractors 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), measures how efficiently an air conditioner cools your home over a standard cooling season. A SEER2 rating is the updated version of SEER, using test procedures that better simulate real-world operating conditions. Most new air conditioners have a SEER2 designation, simply because this is the updated rating system for cooling equipment.
Fuel-burning heating system efficiency is measured by something called AFUE, which is short for Annual Fuel Utilization Efficiency. As with SEER and SEER2, 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.
That said, high ratings don't necessarily guarantee lower utility bills. Real-world heating and air conditioner efficiency depends on many factors, including the quality of the installation, the condition of your ductwork, your home's insulation, thermostat settings and, most importantly, HVAC system sizing. Even the highest-rated system cannot deliver peak performance if it is bigger than necessary or undersized for the home.
Why Proper HVAC Sizing Matters More Than You Think
Many assume a larger air conditioner or furnace will work the best or that they should simply replace their old HVAC system with a same-sized replacement. 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 contractors perform an HVAC load calculation, also called a Manual J calculation, before suggesting replacement equipment. A Manual J calculation considers many factors that affect your home's heating and cooling load, including:
- Total square footage
- Room height
- Window size and direction
- Insulation
- Drafts and air leakage
- Local climate
- Household occupants
- Heat generated by appliances and lighting
- Ductwork condition
A properly sized air conditioner runs long enough to cool your home more uniformly while eliminating excess humidity. That means steadier temperatures, better indoor comfort and improved humidity control. It also helps the equipment to perform more effciently, reducing strain that can shorten its lifespan or lead to costly breakdowns.
When a furnace or AC is properly sized, you get better comfort and long-lasting performance.
Problems Caused by Oversized and Undersized HVAC Equipment
Many homeowners are tempted to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. However, that often isn't a smart choice.
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 work quickly, but that doesn't mean it delivers the best comfort.
- Short cycling: An oversized HVAC system cycles repeatedly, reducing efficiency and increasing wear.
- High indoor humidity: Oversized air conditioners cool your home too quickly 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 reaches the target temperature rapidly, those frequent starts and stops can cause avoidable breakdowns due to the strain.
Cons Associated with Undersized HVAC Systems
An undersized HVAC system has a different set of problems:
- Continuous operation: The system operates almost continuously trying to reach the thermostat setting, which also causes additional wear.
- Difficulty reaching thermostat settings: Your home may feel cool enough during hot weather or always feel chilly in the winter.
- Greater energy usage: Running almost constantly can increase energy costs.
- 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.
Balancing Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, remember that you don't necessarily need the most efficient model on the market.
Often, a correctly sized, mid-efficiency heating and cooling system will deliver better performance than 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:
- 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 reduce long-term energy costs.
- Electricity rates: Areas with higher electricity rates may see greater long-term savings from higher-efficiency units.
- Seasonal weather conditions: It's important your heating or cooling system has adequate capacity to handle areas with very cold winters or intense summer heat.
- 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.
- Available rebates or tax incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can lower the overall cost of higher-efficiency systems.
Real-World Example: High Seer vs. Right System Size
How does this play out in the real world?
Imagine two neighboring homes.
At the first home, 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. Next door, the second homeowner installs a right-sized, mid-SEER or AFUE system after completing a Manual J calculation.
Although the second system has a more modest efficiency rating on paper, it may deliver lower operating costs, better home comfort, improved humidity control and have a longer lifespan because it's correctly matched to the home's needs.
Choose the Local HVAC Professional Who Designs Solutions Tailored to Your Home
Replacing your HVAC system should involve more than selecting a system with the top efficiency rating. The best system is one that meets your home’s heating and cooling requirements.
At Advanced Service AC & Heating, our knowledgeable technicians perform an HVAC load calculation. We'll evaluate your home's layout and construction, your household's heating and cooling preferences 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 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 Advanced Service AC & Heating today. We'll evaluate your home, answer your questions and help you choose the correctly sized efficient system that keeps your family comfortable for years to come.
