HVAC Myths Debunked: What You Need to Know
- DH Heating & Cooling
- Mar 23
- 4 min read
When it comes to your heating and cooling system, there’s no shortage of advice floating around online—and unfortunately, a lot of it is outdated or just plain wrong. Believing common HVAC myths can lead to poor system performance, higher energy bills, and even premature system failure.
At DH Mechanical, we believe that HVAC myths debunked and an informed homeowner is an empowered one. In this blog, we’ll tackle the most common HVAC myths, explain what the truth really is, and help you make smarter decisions about maintaining and upgrading your system.
✅ Myth #1: You Only Need to Change Your Filter Once a Year
This is one of the most common and harmful myths in the HVAC world. Your system’s air filter collects dust, pollen, pet dander, and other pollutants that would otherwise circulate throughout your home.
Reality: Most homes should change their air filters every 1–3 months, depending on usage, pets, allergies, and indoor air quality needs.
✔ Pro Tip: Check your filter monthly. If it looks dirty, replace it. Clean filters keep your HVAC system running efficiently and extend its lifespan.
Read about air filter maintenance from FilterBuy
✅ Myth #2: Bigger HVAC Systems Are Always Better
It might seem logical that a larger HVAC system would cool or heat your home faster—but this is a costly misconception.
Reality: An oversized HVAC unit will short cycle, meaning it turns on and off frequently. This wastes energy, increases wear and tear, and causes uneven temperatures throughout the home.
✔ Pro Tip: Proper system sizing is key. A certified HVAC technician should perform a Manual J Load Calculation to determine the ideal system size for your home.
Learn about HVAC sizing and Manual J calculations at HVAC.com
✅ Myth #3: Closing Vents in Unused Rooms Saves Energy
Many homeowners believe that closing vents in unused rooms redirects airflow to the rest of the house and saves money.
Reality: Closing vents can actually increase system pressure, which forces your HVAC system to work harder and can lead to duct leaks or equipment damage.
✔ Pro Tip: Instead of closing vents, consider zoning systems or smart dampers for better temperature control.
Discover zoning systems at Arzel Zoning Technology
✅ Myth #4: Setting the Thermostat Higher or Lower Will Heat or Cool Faster
It’s a common belief that cranking the thermostat will speed up the process. But your HVAC system works at a fixed rate, no matter the setting.
Reality: Setting the thermostat far above or below your target temperature just causes your system to run longer, using more energy.
✔ Pro Tip: Use a programmable or smart thermostat to gradually adjust temperatures when you're away or sleeping.
Explore thermostat efficiency tips from Emerson
✅ Myth #5: Maintenance Is Optional If Your System Is Working
Some homeowners skip routine maintenance, thinking it’s unnecessary unless there’s a problem.
Reality: Lack of maintenance leads to efficiency loss, poor indoor air quality, and unexpected breakdowns—especially during extreme weather.
✔ Pro Tip: Schedule HVAC maintenance at least twice a year—once before summer and once before winter.
See the benefits of regular maintenance from Service Champions
✅ Myth #6: All HVAC Technicians Are the Same
Choosing the cheapest service provider may seem like a money-saver, but experience, certifications, and reputation matter more than price alone.
Reality: HVAC systems are complex and require proper diagnosis, high-quality parts, and expert installation. Inexperienced technicians can do more harm than good.
✔ Pro Tip: Choose a licensed, insured contractor with positive reviews, NATE-certified technicians, and transparent pricing.
Understand NATE certification from North American Technician Excellence
✅ Myth #7: Duct Tape Is Good for Sealing Ducts
Despite the name, standard duct tape is not suitable for sealing HVAC ducts.
Reality: Duct tape deteriorates over time when exposed to heat. Instead, use foil-backed tape or mastic sealant for long-term duct sealing.
✔ Pro Tip: Have a professional inspect and seal your ductwork to improve efficiency and airflow.
See duct sealing recommendations from Home Energy Magazine
✅ Myth #8: HVAC Systems Don’t Affect Indoor Air Quality
Many believe HVAC systems simply regulate temperature—but they also filter, ventilate, and dehumidify your indoor air.
Reality: Poor HVAC performance can lead to mold growth, allergens, and stale air—all of which can impact your health.
✔ Pro Tip: Upgrade your filter (MERV 11 or higher), clean ductwork, and consider adding air purifiers or UV systems.
✅ Myth #9: New HVAC Systems Don’t Need Maintenance
It’s a myth that newer systems are maintenance-free. Even brand-new units require servicing to stay in peak condition.
Reality: New systems have warranties that often require proof of regular maintenance to remain valid.
✔ Pro Tip: Keep a record of all HVAC service visits and follow your manufacturer's maintenance schedule.
Review HVAC warranty terms from Goodman Manufacturing
Final Thoughts: HVAC myths debunked
Misinformation can cost homeowners time, money, and comfort. By understanding the truth behind common HVAC myths, you can make informed decisions and keep your system operating at peak performance year-round.
📞 Need a trusted HVAC expert in Northeast Indiana? Contact DH Mechanical today for honest advice, energy-efficient solutions, and expert service!
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