Shopping for a new air conditioner or furnace can be intimidating. If you want to find the best HVAC system for your home, it's natural to focus on models with the highest efficiency ratings.
Surely the most efficient equipment will provide the most comfort and lowest energy bills, right?
Not necessarily.
Energy efficiency isn't the only thing that matters when it comes to new air conditioner installation or replacing your furnace. Although many people focus only on efficiency ratings, 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 system longevity. The best HVAC system for your home balances efficiency and proper 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 experienced HVAC professionals 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), measures how effectively an AC cools your home over a typical cooling season. A SEER2 rating is the newer version of SEER, using testing methods that better reflect real-world operating conditions. Most new air conditioners have a SEER2 rating, simply because this is the updated rating system for cooling equipment.
Fuel-burning heating system efficiency is evaluated by AFUE, which stands for Annual Fuel Utilization Efficiency. As with cooling efficiency ratings, 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 numbers don't automatically guarantee lower utility bills. Actual heating and air conditioner efficiency depends on more than just efficiency ratings, including the way the system is installed, the condition of your ductwork, your home's insulation, thermostat settings and, most importantly, proper HVAC system sizing. Even the most efficient system cannot perform as intended if it is oversized or smaller than needed 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 just replace their old HVAC system with a same-sized replacement. The truth is, 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 capacity of the old system.
That's why reputable technicians conduct 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 comfort needs, including:
- Home square footage
- Room height
- Window size and direction
- Insulation
- Air leakage
- Local climate
- Household occupants
- Heat generated by appliances and lighting
- Air duct condition
A properly sized air conditioner runs long enough to cool your home more uniformly while eliminating excess humidity. That means more consistent temperatures, better indoor comfort and improved indoor humidity management. This also allows the equipment to perform more effciently, reducing strain that can shorten its lifespan or lead to costly breakdowns.
When your heating or cooling system is correctly sized, you get improved comfort and more reliable operation.
Problems Caused by Oversized and Undersized Systems
It might be tempting to buy the most energy efficient, largest-capacity air conditioner or heating system on the market. In reality, that often isn't a good investment.
heating and cooling systems that are bigger than your home needs or smaller than your home requires can create comfort problems, 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 reach the thermostat setting fast, but that doesn't mean it delivers the best comfort.
- Short cycling: An oversized HVAC system cycles repeatedly, reducing efficiency and increasing equipment strain.
- High indoor humidity: Oversized air conditioners finish cooling cycles too soon to remove enough moisture from the air.
- Inconsistent temperatures: Some rooms become too cold while others aren’t ever cool enough.
- More wear and tear: Even though the system heats or cools your home fast, 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 operates almost continuously trying to reach the desired temperature, which also causes extra strain.
- Trouble reaching the thermostat setting: Your home may never feel as cool as you want during hot weather or feel too cool during winter.
- Increased energy consumption: Running nonstop can increase energy costs.
- Greater strain on very hot or cold days: HVAC systems that are too small can run extremely hard in extreme temperatures, increasing equipment wear and the risk of breakdowns.
Why You Should Balance HVAC System Efficiency and Size
When trying to decide between a high SEER vs right-sized system, remember that you don't necessarily need the most efficient model on the market.
Often, a professionally sized, mid-efficiency heating and cooling system will deliver better performance than an overly large premium system because it functions the way it was designed to.
Thebest choice is an energy-efficient HVAC system that's properly sized for your home, your budget, your climate and your long-term needs.
When deciding how to choose a new air conditioner or furnace, keep these factors in mind:
- Lower energy costs: Higher-efficiency and right-sized systems can reduce electricity use.
- Purchase price: High-efficiency AC and heating systems often require a larger upfront investment than mid-range models but can reduce long-term energy costs.
- Electricity rates: Areas with higher electricity rates may see greater long-term savings from higher-efficiency units.
- Your local climate: It's important your heating or cooling system has enough capacity to handle areas with harsh winter weather 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 be worth the investment.
- Financial incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can lower the overall cost of high-efficiency HVAC equipment.
Real-World Example: High Seer vs. Right System Size
How does this work in the real world?
Imagine two neighboring homes.
At the first home, the homeowner chooses a premium high-efficiency HVAC system that's too big for the house 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 more modest efficiency rating on paper, it may provide lower operating costs, better home comfort, improved humidity control and have a longer lifespan because it's correctly matched to the home's needs.
Work With an HVAC Professional Who Designs Solutions Tailored to Your Home
Replacing your HVAC system should involve more than selecting a system with the highest efficiency rating. The best system is one that meets your household heating and cooling requirements.
At R&R Cooling Solutions, our experienced professionals perform an HVAC load calculation. We'll evaluate your home's design, your household's heating and cooling preferences and recommend equipment that's right for your home—not simply the largest, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our heating and cooling specialists 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 R&R Cooling Solutions today. We'll gladly evaluate your home, answer any questions and help you choose the properly sized high-efficiency system that keeps your family comfortable for the long haul.