Choosing a new AC or furnace can be intimidating. If you're trying to find the best HVAC system for your home, it's common to focus on models with the highest efficiency ratings.
Surely the most efficient heating and cooling system provides 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 installing a new furnace. Although many people focus only on energy efficiency, proper HVAC system sizing is equally, if not more important for your home's comfort and your energy bills.
Proper sizing has a major impact on humidity control and lasting performance. 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 qualified HVAC contractors consider both when helping you select the best HVAC system for your home.
High Seer Ratings: What Do They Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), shows how effectively an air conditioner 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 rating, simply because that is the updated rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by an AFUE rating, which stands for Annual Fuel Utilization Efficiency. Similar to 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.
Even so, high numbers don't by themselves guarantee lower utility bills. Real-world heating and air conditioner efficiency depends on many factors, including the way the system is installed, the state 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 a new air conditioner should be sized 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 considers many variables that affect your home's heating and cooling requirements, including:
- Total square footage
- Ceiling height
- Window size and direction
- Insulation
- Air infiltration
- Regional climate
- Household occupants
- Heat produced from appliances and lighting
- Air duct condition
A properly sized air conditioner runs through longer cooling cycles to cool your home more uniformly while eliminating excess humidity. That means more consistent temperatures, better indoor comfort and improved indoor humidity management. Proper sizing also helps the equipment to run more effciently, reducing strain that can reduce its service life or lead to frequent or expensive repairs.
When HVAC equipment is the right size for your home, you get better comfort and long-lasting performance.
Problems Caused by Oversized and Undersized Heating and Cooling Systems
It might be tempting to buy the most energy efficient, largest-capacity air conditioner or heating system on the market. The truth is, that often isn't a smart choice.
heating and cooling systems that are too large or too small 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 turns on and off frequently, reducing efficiency and increasing wear and tear.
- Poor humidity removal: Oversized air conditioners reach the set temperature too fast to remove excess moisture from the air.
- Uneven temperatures: Some rooms feel too cool while others stay too warm.
- Increased wear and tear: Even though the system heats or cools your home fast, those repeated on-and-off cycles can cause avoidable breakdowns due to the strain.
Issues Created by Undersized HVAC Systems
An undersized HVAC system has a different set of problems:
- Long run times: The system stays on for extended periods 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 feel too cool during winter.
- Greater energy usage: Running for extended periods can increase utility bills.
- Extra stress during severe weather: HVAC systems that are too small can work harder in extreme temperatures, increasing equipment wear and the likelihood of repairs.
Balancing Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, don't forget that you don't automatically need the top-efficiency model on the market.
Often, a professionally sized, mid-efficiency HVAC system will deliver better performance than an oversized premium system because it functions 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.
As you consider 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 lower long-term energy costs.
- Local utility costs: Areas with higher utility costs may see greater long-term savings from higher-efficiency units.
- Seasonal weather conditions: It's important your heating or cooling system has the right capacity to handle areas with very cold winters or intense summer heat.
- Time you plan to 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 high-efficiency HVAC equipment.
Real-World Situation: High Seer vs. Right System Size
How does this play out in a real world example?
Picture two neighboring homes.
In the first, 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. At the neighboring home, an HVAC professional installs a right-sized, mid-efficiency system after completing a Manual J calculation.
While the second system has a lower efficiency rating on paper, it may provide lower operating costs, better home comfort, more effective humidity control and last longer because it's appropriately sized to the home's needs.
Choose the Local HVAC Professional Who Designs Solutions Tailored to Your Home
Replacing your HVAC system should involve much more than selecting the unit with the highest efficiency rating. The right system is one that meets your household heating and cooling requirements.
At McFadden Heating & Cooling, our experienced professionals perform an HVAC load calculation. We'll evaluate your home's layout and construction, your household's comfort needs 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 heating and cooling specialists will let you know about 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 McFadden Heating & Cooling to get started. Our team will 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.
