Shopping for a new air conditioning system or furnace can be intimidating. When you're looking to find the best HVAC system for your home, it's common to focus on models with extremely high efficiency ratings.
After all, the most efficient equipment should deliver the most comfort and lowest energy bills, right?
Not necessarily.
High efficiency isn't the only thing that matters when it comes to new air conditioner installation or furnace replacement. 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 has a major impact on humidity control and long-term reliability. The best HVAC system for your home delivers efficiency and proper sizing.
In this article, we'll explain what an air conditioner's SEER rating or SEER2 rating actually measures, why correct HVAC size is so important and why experienced HVAC professionals consider both when recommending the best HVAC system for your home.
What Does a High SEER Rating Actually Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), measures how effectively a cooling system cools your home over a normal 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 updated rating system for cooling equipment.
Fuel-burning heating system efficiency is measured by AFUE, which is short for Annual Fuel Utilization Efficiency. Similar to cooling efficiency 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.
That said, high numbers don't by themselves guarantee lower utility bills. Actual heating and air conditioner efficiency depends on many factors, including the installation quality, 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 oversized or undersized for the home.
Why HVAC System Size Matters More Than Most Homeowners Realize
Many assume a bigger air conditioner or furnace will work the best or that they should just replace their old HVAC system with a same-sized replacement. The truth is, new heating system installation or AC replacement should be chosen 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 conduct an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation evaluates many factors that affect your home's heating and cooling requirements, including:
- Overall square footage
- Room height
- Window size and placement
- Home insultation levels
- Air leakage
- Local climate
- Household occupants
- Heat generated by appliances and lighting
- Ductwork condition
A properly sized air conditioner runs through longer cooling cycles to cool your home more uniformly while pulling out excess humidity. That means steadier temperatures, better indoor comfort and improved humidity control. It also helps the equipment to perform more effciently, reducing unnecessary wear that can shorten its lifespan or lead to more repairs and higher repair costs.
When HVAC equipment is properly sized, you get improved comfort and more reliable operation.
Problems Caused by Oversized and Undersized Systems
Many homeowners are tempted to buy the most energy efficient, biggest air conditioner or heating system on the market. In reality, that's usually not a smart choice.
heating and cooling systems that are too large or too small can create indoor comfort challenges, 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 works well.
- Short cycling: An oversized HVAC system starts and stops often, reducing efficiency and increasing equipment strain.
- Humidity problems: Oversized air conditioners cool your home too quickly to remove enough moisture 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 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:
- Long run times: The system operates almost continuously trying to reach the thermostat setting, which also causes extra strain.
- Difficulty maintaining the desired temperature: Your home may feel cool enough during hot weather or never feel warm enough in cold weather.
- Greater energy usage: Running nonstop can increase utility bills.
- Added strain during extreme weather: HVAC systems that are too small can work harder in extreme temperatures, increasing wear and the chance of failure.
Why You Should Balance HVAC System Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, remember that you don't always need the highest-efficiency model on the market.
In many cases, a correctly sized, mid-efficiency heating and cooling system will outperform an overly large premium system because it runs the way it was designed to.
Thebest choice is an energy-efficient HVAC system that's properly sized for your home, your budget, your climate and your future plans.
As you think about 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 cost more initially than mid-range models but can reduce long-term energy costs.
- Electricity rates: Areas with more expensive electricity 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 extremely cold winters or extremely 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.
- Rebates and tax credits: 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?
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. The other homeowner installs a right-sized, moderate-efficiency system after completing a Manual J calculation.
While the second system has a lower efficiency rating on paper, it may deliver 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 Local HVAC Professional Who Designs the Right Solution
HVAC replacent or installation should involve more than selecting the unit with the top efficiency rating. The right system is one that meets your heating and cooling requirements.
At Classic Air, our experienced professionals perform an HVAC load calculation. Our team will evaluate your home's size and layout, your household's heating and cooling preferences and recommend equipment that's right for your home—not simply the biggest, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our HVAC experts will help you identify any available rebates and 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 Classic Air today. We'll evaluate your home, answer any questions and help you choose the correctly sized efficient system that keeps your family comfortable for the long haul.