HVAC Myths Every Homeowner Should Know

When it comes to your home’s HVAC system, misinformation can lead to costly mistakes. Homeowners often believe common myths about heating and air conditioning systems that can end up wasting energy, money, or even damaging the equipment. HVAC.com sets the record straight by debunking some of the most common HVAC myths every homeowner should know.

Myth: Bigger HVAC Systems Are Always Better

Truth: Bigger is not better in the case of your HVAC system. A unit that is too large for your home will cycle on and off too frequently. This is called short cycling and it can lead to temperature imbalances, increased energy usage, and more wear on the system, ultimately shortening its lifespan. A properly sized unit will run more consistently, keep temperatures more even, and save you money on energy bills in the long run.

Myth: You Only Need to Change the Air Filter Once a Year

Truth: Most air filters need to be replaced every 30 to 90 days, depending on the type of filter, whether you have pets, and how often you use your system. A dirty filter restricts airflow, causing the system to work harder, increasing energy costs, and potentially leading to overheating or freezing issues. 

Myth: All Air Filters Are the Same

Truth: Not all air filters are created equal. Filters are rated based on their Minimum Efficiency Reporting Value (MERV), which indicates how well they capture particles. While a higher MERV rating means better filtration, it also means the filter is more restrictive, which can put strain on your HVAC system if it isn’t designed for it. For most homes, a MERV 8 filter strikes a good balance between efficiency and airflow. 

Myth: Leaving Your HVAC Fan Running All the Time Improves Air Quality

Truth: While it’s true that the fan helps move air through your home, constantly running it can actually have the opposite effect. The fan can pick up dust, dirt, and allergens from your ducts and recirculate them, potentially worsening your air quality if your ducts aren’t clean. For optimal air quality, it’s better to run it in “auto” mode, which only turns the fan on when your system is actively heating or cooling.

Myth: Closing Vents in Unused Rooms Saves Energy

Truth: It’s understandable that you might think closing air vents in rarely used rooms can save money. However, closing vents creates air pressure imbalances that can cause duct leaks, reduced airflow, and damage to your system’s blower motor. Instead of closing vents, a zoning system can be installed alongside your HVAC system to better control the temperature in different parts of your home.

Myth: Cranking Up the Heat on a Cold Day Will Warm Your Home Faster

Truth: Heating systems don't work faster when you set the thermostat higher. Your furnace will heat your home at a steady rate regardless of the setting. When you turn up the thermostat much higher than you need, it’s easy to forget to turn it back down to normal once your home is warm, which wastes energy.

Myth: Turning Your HVAC System Off When You’re Away Saves Energy

Truth: Turning your HVAC system completely off forces the system to work harder when it’s turned back on to reach the desired temperature, using more energy in the process. A better approach is to lower the temperature. Smart and programmable thermostats can be programmed to reduce heating or cooling when you’re away and bring it back to a comfortable level before you return. 

Myth: Your HVAC System Doesn’t Need Maintenance if It’s Running Fine

Truth: Much like a car, an HVAC system needs routine maintenance to run efficiently and to catch minor issues before they cause damage to the system. Scheduling a heating tune-up in the fall and a cooling tune-up in the spring allows a professional to inspect and clean your system, check for any signs of wear, and make necessary adjustments.

Myth: A Programmable Thermostat Automatically Saves You Money

Truth: While a programmable thermostat has the potential to save energy, it only works if you set it properly. Many homeowners install programmable thermostats but don’t take the time to adjust the settings based on their schedule. To maximize efficiency, program your thermostat to adjust the temperature when you’re asleep or away from home. 

Myth: Ceiling Fans Keep a Room Cool

Truth: Ceiling fans don’t actually cool the air. Fans work by creating a wind-chill effect, making it feel cooler when you’re in the room, but they don’t lower the actual temperature. If you leave ceiling fans on when no one is in the room, you’re just wasting energy. 

Myth: Duct Tape is the Best Way to Seal Leaks in Ductwork

Truth: Despite its name, duct tape isn’t the best solution for sealing leaks in ductwork. Over time, the adhesive on duct tape can deteriorate, especially in the high heat of HVAC systems. Instead, professionals use mastic sealant or aluminum foil tape to properly seal duct leaks.

Myth: All HVAC Systems Are the Same

Truth: Not all HVAC systems are created equal. Systems vary in terms of efficiency, size, and technology. Some may be better suited for certain homes based on climate, size, or personal preferences. For example, a heat pump might be a great choice for milder climates, while a high-efficiency furnace is ideal for colder areas.

Myth: It’s Okay to Run the AC With the Windows Open

Truth: This is a big energy waster and one of the most inefficient ways to use your AC. When windows are open, your AC has to work much harder because it’s constantly trying to cool down the hot air coming in from outside. This puts unnecessary strain on your system, causing it to use more energy and experience more wear and tear.

Myth: Air Quality Improves by Simply Running the HVAC System

Truth: While your HVAC system circulates air throughout your home, it doesn’t necessarily clean it or improve its quality unless it has the right components in place. For your HVAC system to truly enhance indoor air quality, you need proper filtration and ventilation.