Choosing a new air conditioner or furnace can be intimidating. If you're trying to find the best HVAC system for your home, it's natural to focus on models with extremely high efficiency ratings.
After all, the most efficient system will provide the most comfort and lowest energy bills, right?
Not necessarily.
Efficiency ratings aren’t the only thing to think about 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 utility bills.
Proper sizing has a major impact on humidity control and lasting performance. The best HVAC system for your home combines efficiency and correct sizing.
In this blog, 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), shows how effectively an air conditioner cools your home over a normal cooling season. A SEER2 rating is the newer version of SEER, using evaluation methods that better reflect real-world operating conditions. Most new air conditioners have a SEER2 rating, simply because this is the current rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by AFUE, which is short for Annual Fuel Utilization Efficiency. Similar to 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.
However, high ratings don't necessarily guarantee lower utility bills. Everyday heating and air conditioner efficiency depends on several key factors, including the quality of the installation, the quality of your ductwork, your home's insulation, thermostat settings and, most importantly, system sizing. Even the highest-rated system cannot perform as intended if it is oversized or smaller than needed for the home.
Why Correct HVAC System Sizing Matters More Than You 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 new one the same size. Actually, new heating system installation or air conditioner replacement should be sized based on your home's true 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 considers many variables that impact your home's heating and cooling requirements, including:
- Home square footage
- Ceiling height
- Window size and orientation
- Insulation
- Drafts and air leakage
- Area climate
- Number of 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. It also helps the equipment to perform more effciently, reducing excessive wear and tear that can shorten its lifespan or lead to costly breakdowns.
When a furnace or AC is properly sized, you get improved comfort and more dependable performance.
Problems Caused by Oversized and Undersized HVAC Equipment
It might be tempting to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. The truth is, that's usually not a smart choice.
HVAC systems that are too large or undersized can create indoor comfort challenges, increase utility costs and reduce efficiency regardless of their SEER rating.
Issues Created by Oversized HVAC Systems
An oversized air conditioner or heating system may heat or cool rapidly, but that doesn't mean it delivers the best comfort.
- Short cycling: An oversized HVAC system turns on and off frequently, reducing efficiency and increasing wear.
- Reduced humidity control: Oversized air conditioners cool your home too quickly to remove excess moisture from the air.
- Hot and cold spots: Some rooms feel too cool while others never feel comfortable.
- Additional equipment wear: 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 also can struggle:
- Long run times: The system runs for long periods trying to reach the thermostat setting, which also causes additional wear.
- Difficulty maintaining the desired temperature: Your home may never feel as cool as you want during hot weather or never feel warm enough in cold weather.
- Higher energy use: Running for extended periods can increase energy costs.
- Added strain during extreme weather: HVAC systems that are too small can run extremely hard in extreme temperatures, increasing equipment wear 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 always need the top-efficiency model on the market.
More often than not, a professionally sized, mid-efficiency HVAC system will outperform an overly large premium system because it operates the way it was designed to.
Thesmartest choice is an energy-efficient HVAC system that's matched for your home, your budget, your climate and your future plans.
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.
- Initial cost: High-efficiency AC and heating systems often require a larger upfront investment than mid-range models but can help reduce 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 important your heating or cooling system has adequate capacity to handle areas with very cold winters or extremely hot summers.
- Length of home ownership: 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.
- Rebates and tax credits: Manufacturer promotions, {utility|equipment rebates and tax credits can reduce the overall cost of qualifying equipment.
Real-World Example: High Seer vs. Right System Size
How does this work in a real world example?
Suppose there are two neighboring homes.
At the first home, the homeowner chooses a premium high-efficiency HVAC system has far more capacity than the home needs because the contractor simply matched the previous unit. At the neighboring home, an HVAC professional installs a correctly sized, mid-SEER or AFUE system after completing a Manual J calculation.
Even though 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
Replacing your HVAC system should involve more than selecting a system with the highest efficiency rating. The best system is one that meets your heating and cooling requirements.
At Scott Temperature, our knowledgeable technicians perform an HVAC load calculation. We'll carefully evaluate your home's layout and construction, your household's comfort needs and recommend equipment that's designed specifically for your home—not simply the highest-capacity, most expensive unit or the one with the highest AFUE or SEER2 rating.
Our HVAC experts will help you identify any available rebates or tax incentives and provide information about HVAC financing options that make high-efficiency systems more accessible for all budgets.
Schedule an HVAC consultation online with Scott Temperature to get started. We'll evaluate your home, answer any questions and help you choose the properly sized high-efficiency system that keeps your family comfortable for years to come.