Shopping for a new air conditioning system or furnace can be intimidating. If you're trying to find the best HVAC system for your home, it's understandable to look for models with the highest efficiency ratings.
Surely the most efficient system will provide the most comfort and lowest energy bills, right?
It’s not quite that simple.
Energy efficiency isn't the only thing you should consider when it comes to new air conditioner installation or installing a new furnace. While many homeowners focus only on efficiency ratings, proper HVAC system sizing is often even 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 combines energy 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 size 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 efficiently an AC cools your home over a normal cooling season. A SEER2 rating is the newer version of SEER, using test procedures that better reflect real-world operating conditions. Today’s new air conditioners have a SEER2 rating, simply because this rating is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is measured by AFUE, which is for Annual Fuel Utilization Efficiency. Like SEER and SEER2, 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.
That said, high numbers don't automatically guarantee lower utility bills. Everyday heating and air conditioner efficiency depends on many 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 most efficient system cannot operate at its best if it is oversized or smaller than needed for the home.
Why Correct HVAC System Sizing Matters More Than You Probably Think
Many assume a bigger air conditioner or furnace will make their home the most comfortable or that they should just replace their old HVAC system with a new one the same size. The truth is, new heating system installation or a new air conditioner should be sized based on your home's true heating and cooling needs—not just square footage or the capacity of the old system.
That's why reputable technicians perform an HVAC load calculation, also called a Manual J calculation, before selecting replacement equipment. A Manual J calculation analyzes many factors that impact your home's heating and cooling load, including:
- Home square footage
- Ceiling height
- Window size and placement
- Home insultation levels
- Air infiltration
- Regional climate
- Household occupants
- Heat produced from appliances and lighting
- Ductwork condition
A properly sized air conditioner runs long enough to cool your home evenly while pulling out excess humidity. That means more even temperatures, better indoor comfort and improved indoor humidity management. Proper sizing also helps the equipment to run more effciently, reducing unnecessary wear that can cause it to wear it out sooner or lead to costly breakdowns.
When HVAC equipment is the right size for your home, you get greater comfort and more reliable operation.
Problems Caused by Oversized and Undersized Systems
You may be tempted to buy the most energy efficient, largest-capacity air conditioner or heating system on the market. In reality, that's usually not a smart choice.
HVAC systems that are bigger than your home needs or too small can create comfort issues, increase energy expenses and reduce efficiency regardless of their SEER rating.
Drawbacks of 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 turns on and off frequently, reducing efficiency and increasing equipment strain.
- High indoor humidity: Oversized air conditioners cool your home too quickly to remove indoor humidity from the air.
- Hot and cold spots: Some rooms feel too cool while others aren’t ever cool enough.
- More wear and tear: Even though the system reaches the target temperature rapidly, those constant cycles can cause avoidable breakdowns due to the strain.
Drawbacks of Undersized HVAC Systems
An undersized HVAC system can have the opposite problem:
- Continuous operation: The system stays on for extended periods trying to reach the thermostat setting, which also causes additional wear.
- Difficulty reaching thermostat settings: Your home may never feel as cool as you want during hot weather or always feel chilly in the winter.
- Greater energy usage: Running for extended periods can increase energy costs.
- Added strain during extreme weather: HVAC systems that are too small can struggle in extreme temperatures, increasing component strain and the chance of failure.
Balancing Efficiency and Size
When trying to decide between a high SEER vs right-sized system, remember that you don't always need the highest-efficiency model on the market.
Often, a properly sized, mid-efficiency heating and cooling system will outperform an overly large premium system because it runs the way it was designed to.
Theideal choice is an energy-efficient HVAC system that's properly sized for your home, your budget, your climate and your future plans.
When deciding how to choose a new air conditioner or furnace, consider:
- Efficiency savings: Higher-efficiency and right-sized systems can decrease electricity use.
- Upfront investment: High-efficiency AC and heating systems often cost more initially than mid-range models but can reduce long-term energy costs.
- Local utility costs: Areas with higher utility costs may see better long-term savings from higher-efficiency units.
- Climate: It's essential your heating or cooling system has adequate capacity to handle areas with harsh winter weather 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.
- Available rebates or tax 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
What does this look like in the real world?
Imagine 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. Next door, the second homeowner installs a right-sized, mid-efficiency system after completing a Manual J calculation.
Although the second system has a more modest efficiency rating on paper, it may provide 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.
Choose the HVAC Professional Who Designs the Right Solution
An HVAC replacement should involve more than selecting the unit with the highest efficiency rating. The right system is one that meets your home’s heating and cooling requirements.
At Kilbourne Heating & AC, our skilled HVAC experts perform an HVAC load calculation. We'll evaluate your home's size and layout, your household's comfort needs 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 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 Kilbourne Heating & AC to get started. We'll gladly evaluate your home, answer any questions and help you choose the right-sized energy-efficient system that keeps your family comfortable for years to come.