Shopping for a new AC or furnace can be intimidating. When you're looking to find the best HVAC system for your home, it's understandable to focus on models with the highest efficiency ratings.
After all, the most efficient equipment provides the most comfort and lowest energy bills, right?
It’s not quite that simple.
High efficiency isn't the only thing you should consider when it comes to new air conditioner installation or replacing your furnace. Even though many focus only on efficiency ratings, proper HVAC system sizing is often even more important for your home's comfort and your power bills.
Proper sizing also influences humidity control and long-term reliability. The best HVAC system for your home delivers efficiency and correct 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 trusted HVAC experts consider both when helping you select 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), indicates how efficiently an AC cools your home over a normal cooling season. A SEER2 rating is the updated version of SEER, using testing methods that better represent real-world operating conditions. Today’s 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. 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.
Even so, 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 quality of your ductwork, insulation levels, thermostat settings and, most importantly, HVAC system sizing. Even the highest-rated system cannot deliver peak performance if it is too large or smaller than needed for the home.
Why HVAC System Size Matters More Than You Think
Many assume a larger air conditioner or furnace will work the best or that they should just replace their old HVAC system with a unit of the same capacity. Actually, new heating system installation or a new air conditioner should be sized based on your home's actual heating and cooling needs—not just square footage or the capacity of the old system.
That's why reputable companies perform an HVAC load calculation, also called a Manual J calculation, before suggesting replacement equipment. A Manual J calculation evaluates many factors that impact your home's heating and cooling load, including:
- Overall square footage
- Room height
- Window size and placement
- Insulation
- Air infiltration
- Area climate
- Number of occupants
- Heat generated by appliances and lighting
- Ductwork condition
A properly sized air conditioner runs through longer cooling cycles to cool your home consistently while removing excess humidity. That means more even temperatures, better indoor comfort and improved humidity control. This also allows the equipment to run more effciently, reducing unnecessary wear that can cause it to wear it out sooner or lead to frequent or expensive repairs.
When a furnace or AC is the right size for your home, you get improved comfort and long-lasting performance.
Problems with Oversized and Undersized Systems
Many homeowners are tempted to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. In reality, that often isn't a great idea.
HVAC systems that are bigger than your home needs or undersized can create comfort problems, increase operating costs and reduce efficiency regardless of their SEER rating.
Drawbacks of 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 cycles repeatedly, reducing efficiency and increasing equipment strain.
- Humidity problems: Oversized air conditioners finish cooling cycles too soon to remove excess moisture from the air.
- Uneven temperatures: Some rooms get too cold while others stay too warm.
- More wear and tear: Even though the system reaches the target temperature rapidly, those repeated on-and-off cycles can cause avoidable breakdowns due to the strain.
Cons Associated with Undersized HVAC Systems
An undersized HVAC system can have the opposite problem:
- 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.
- Greater energy usage: Running nonstop can increase energy costs.
- Extra stress during severe weather: HVAC systems that are too small can struggle in extreme temperatures, increasing wear and the likelihood of repairs.
Balancing Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, keep in mind that you don't always need the highest-efficiency model on the market.
Often, a properly sized, mid-efficiency HVAC system will deliver better performance than an overly large premium system because it runs the way it was designed to.
Thebest choice is an energy-efficient HVAC system that's correctly 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:
- Lower energy costs: Higher-efficiency and right-sized systems can decrease electricity use.
- Purchase price: High-efficiency AC and heating systems often have a higher purchase price than mid-range models but can lower long-term energy costs.
- Energy prices: Areas with higher utility costs may see more significant long-term savings from higher-efficiency units.
- Seasonal weather conditions: It's essential your heating or cooling system has enough capacity to handle areas with extremely cold winters 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 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
What does this look like in a real world example?
Suppose there are two neighboring homes.
In one, the homeowner chooses a premium high-efficiency HVAC system that's too big for the house because the contractor simply matched the previous unit. The other homeowner installs a properly sized, mid-efficiency system after completing a Manual J calculation.
Even though 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 properly matched to the home's needs.
Choose the HVAC Professional Who Designs Personalized Solutions
Replacing your HVAC system should involve more than selecting a model with the highest efficiency rating. The right system is one that meets your heating and cooling requirements.
At Stanford Heating & Cooling, our skilled HVAC experts perform an HVAC load calculation. We'll evaluate your home's design, your household's heating and cooling preferences 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 HVAC experts will connect you with any available tax rebates and provide information about HVAC financing options that make high-efficiency systems more accessible for all budgets.
Schedule an HVAC consultation online with Stanford Heating & Cooling today. We'll evaluate your home, answer any questions and help you choose the right-sized efficient system that keeps your family comfortable for the long haul.
