Shopping for a new AC or furnace can be stressful. If you want to find the best HVAC system for your home, it's common to look for models with the highest efficiency ratings.
Surely the most efficient heating and cooling system will provide the most comfort and lowest energy bills, right?
Actually, that’s not always the case.
Energy efficiency isn't the only thing that matters when it comes to new air conditioner installation or furnace replacement. Although many people focus only on energy efficiency, proper HVAC system sizing is just as, if not more important for your home's comfort and your power bills.
Proper sizing has a major impact on humidity control and system longevity. The best HVAC system for your home balances efficiency and correct sizing.
In this guide, 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 a High SEER Rating Actually Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), indicates how effectively an AC cools your home over a typical cooling season. A SEER2 rating is the updated version of SEER, using testing methods that better simulate real-world operating conditions. Nearly all new air conditioners have a SEER2 efficiency rating, simply because this is the updated rating system for cooling equipment.
Fuel-burning heating system efficiency is measured by an AFUE rating, which is for Annual Fuel Utilization Efficiency. As with SEER and SEER2 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 more than just efficiency ratings, including the installation quality, the condition of your ductwork, how much insulation your home has, thermostat settings and, most importantly, proper HVAC system sizing. Even the highest-efficiency system cannot deliver peak performance if it is oversized or undersized for the home.
Why Correct HVAC System Sizing 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 just replace their old HVAC system with a same-sized replacement. Actually, 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 companies perform an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation analyzes many details that impact your home's heating and cooling load, including:
- Total square footage
- Room height
- Window size and placement
- Home insultation levels
- Drafts and air leakage
- Local climate
- Number of occupants
- Heat produced from appliances and lighting
- Ductwork 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 moisture control. Proper sizing also helps the equipment to operate more effciently, reducing unnecessary wear that can reduce its service life or lead to costly breakdowns.
When your heating or cooling system is the right size for your home, you get improved comfort and more reliable operation.
Problems Caused by Oversized and Undersized Heating and Cooling Systems
You may be tempted to buy the most energy efficient, largest-capacity air conditioner or heating system on the market. However, that's usually not a smart choice.
heating and cooling systems that are bigger than your home needs or undersized can create comfort problems, increase utility costs and reduce efficiency regardless of their SEER rating.
Common Problems With Oversized HVAC Systems
An oversized air conditioner or heating system may heat or cool rapidly, 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.
- Humidity problems: Oversized air conditioners reach the set temperature too fast to remove excess moisture from the air.
- Inconsistent temperatures: Some rooms feel too cool while others aren’t ever cool enough.
- Additional equipment wear: Even though the system reaches the target temperature rapidly, 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 runs for long periods trying to reach the desired temperature, which also causes extra strain.
- Difficulty maintaining the desired temperature: Your home may not feel comfortable during hot weather or always feel chilly in the winter.
- Higher energy use: Running for extended periods can increase energy costs.
- Added strain during extreme weather: HVAC systems that are too small can work harder in extreme temperatures, increasing component strain 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 top-efficiency model on the market.
Often, a professionally sized, mid-efficiency HVAC system will outperform an overly large premium system because it operates the way it was designed to.
Theideal 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, think about:
- Energy savings: Higher-efficiency and right-sized systems can lower 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 electricity rates may see more significant long-term savings from higher-efficiency units.
- Climate: It's crucial your heating or cooling system has enough capacity to handle areas with very cold winters or intense summer heat.
- 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.
- Financial incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can offset 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?
Picture two neighboring homes.
In the first, the homeowner chooses a premium high-efficiency HVAC system that's too big because the contractor only matched the previous unit. The other homeowner installs a correctly sized, moderate-efficiency system after completing a Manual J calculation.
Although the second system has a lower efficiency rating on paper, it may deliver lower operating costs, better home comfort, more effective humidity control and have a longer lifespan because it's correctly matched to the home's needs.
Work With an HVAC Professional Who Designs the Right Solution
HVAC replacent or installation should involve much more than selecting the unit with the highest efficiency rating. An ideal system is one that meets your household heating and cooling requirements.
At Kohles & Bach Heating & Cooling, our experienced professionals perform an HVAC load calculation. Our team will evaluate your home's size and layout, your household's comfort goals and recommend equipment that's designed specifically for your home—not simply the largest, latest and greatest 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 high-efficiency systems more accessible for all budgets.
Schedule an HVAC consultation online with Kohles & Bach Heating & Cooling today. We'll evaluate your home, answer any questions and help you choose the correctly sized efficient system that keeps your family comfortable for many years.