Shopping for a new AC or furnace can be intimidating. If you want 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 heating and cooling system provides the most comfort and lowest energy bills, right?
Actually, that’s not always the case.
High efficiency isn't the only thing that matters when it comes to new air conditioner installation or installing a new furnace. While many homeowners focus only on energy efficiency, proper HVAC system sizing is often even more important for your home's comfort and your power bills.
Proper sizing directly impacts humidity control and system longevity. The best HVAC system for your home combines efficiency and correct sizing.
In this blog, 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 choose 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 effectively an air conditioner cools your home over a typical cooling season. A SEER2 rating is the newer version of SEER, using evaluation methods that better simulate real-world operating conditions. Nearly all new air conditioners have a SEER2 designation, simply because this is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by something called AFUE, which is for Annual Fuel Utilization Efficiency. Similar to 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.
However, high ratings don't necessarily guarantee lower utility bills. Real-world heating and air conditioner efficiency depends on several key factors, including the way the system is installed, the condition of your ductwork, your home's insulation, thermostat settings and, most importantly, HVAC system sizing. Even the highest-rated system cannot operate at its best if it is too large or undersized for the home.
Why Proper HVAC Sizing Matters More Than You Think
Many assume a higher-capacity air conditioner or furnace will heat or cool a home better or that they should just replace their old HVAC system with a new one the same size. Actually, new heating system installation or air conditioner replacement should be selected based on your home's current heating and cooling needs—not just square footage or the size of your existing equipment.
That's why reputable technicians conduct an HVAC load calculation, also called a Manual J calculation, before suggesting replacement equipment. A Manual J calculation evaluates many variables that impact your home's comfort needs, including:
- Home square footage
- Ceiling height
- Window size and placement
- Insulation
- Air infiltration
- Regional climate
- Number of occupants
- Heat produced from appliances and lighting
- Air duct condition
A properly sized air conditioner runs long enough to cool your home evenly while removing excess humidity. That means steadier temperatures, better indoor comfort and improved moisture control. It also helps the equipment to run more effciently, reducing strain that can reduce its service life or lead to costly breakdowns.
When a furnace or AC is correctly sized, you get greater comfort and long-lasting performance.
Problems Caused by Oversized and Undersized HVAC Equipment
It might be tempting to buy the most energy efficient, biggest air conditioner or heating system on the market. The truth is, that’s rarely a good investment.
heating and cooling systems that are bigger than necessary or too small can create comfort issues, increase operating costs and reduce efficiency regardless of their SEER rating.
Issues Created by 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 turns on and off frequently, reducing efficiency and increasing wear.
- High indoor humidity: Oversized air conditioners finish cooling cycles too soon to remove indoor humidity from the air.
- Hot and cold spots: Some rooms become too cold while others aren’t ever cool enough.
- Increased wear and tear: Even though the system works quickly, those frequent starts and stops 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 operates almost continuously trying to reach the desired temperature, which also causes unnecessary wear and tear.
- Trouble reaching the thermostat setting: Your home may never feel as cool as you want during hot weather or never feel warm enough in cold weather.
- Higher energy use: Running for extended periods can increase monthly energy expenses.
- Added strain during extreme weather: HVAC systems that are too small can run extremely hard in extreme temperatures, increasing equipment wear and the risk of breakdowns.
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 highest-efficiency model on the market.
In many cases, a professionally sized, mid-efficiency heating and cooling system will deliver better performance than an oversized premium system because it runs 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 long-term goals.
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 reduce electricity use.
- Purchase price: 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.
- Your local climate: It's essential your heating or cooling system has enough capacity to handle areas with harsh winter weather or intense summer heat.
- How long you'll own the home: If you plan to stay 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 qualifying equipment.
Real-World Situation: High Seer vs. Right System Size
How does this play out in the real world?
Suppose there are 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 only matched the previous unit. Next door, the second homeowner installs a correctly sized, moderate-efficiency system after completing a Manual J calculation.
Even though the second system has a lesser efficiency rating on paper, it may deliver lower operating costs, better home comfort, improved humidity control and have a longer lifespan because it's properly matched to the home's needs.
Work With an HVAC Professional Who Designs Personalized Solutions
An HVAC replacement should involve more than selecting a model with the top efficiency rating. The best system is one that meets your household heating and cooling requirements.
At Custom Air Systems, our knowledgeable technicians perform an HVAC load calculation. We'll evaluate your home's size and layout, your household's heating and cooling preferences and recommend equipment that's properly matched 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 connect you with 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 Custom Air Systems 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 years to come.