Your HVAC system is one of the hardest-working — and most misunderstood — systems in your home. Misinformation spreads easily, and acting on bad advice can lead to higher energy bills, unnecessary wear on your equipment, or outright system damage.
At Lanz Plumbing, Heating & Cooling, we hear these misconceptions regularly from homeowners across Urbana and the Champaign area. Here’s the truth behind 7 of the most common HVAC myths we encounter.
Myth 1: A Bigger HVAC System Always Performs Better
It seems logical — a larger system should heat or cool your home faster and more efficiently, right? In reality, the opposite is often true.
An oversized HVAC system will short-cycle, meaning it reaches the set temperature too quickly and shuts off before completing a full heating or cooling cycle. This rapid on-off pattern puts excessive wear and tear on components, leads to uneven temperatures throughout your home, and actually increases humidity in the summer because the system doesn’t run long enough to properly dehumidify the air.
The right system for your home is sized based on square footage, insulation levels, window placement, and local climate — not simply “bigger is better.” A professional load calculation ensures your equipment is matched correctly to your space before installation.
Myth 2: HVAC Maintenance Is Only Necessary When Something Goes Wrong
This is one of the most costly myths homeowners believe. Waiting until your system breaks down to call a technician is like skipping all your car’s oil changes and only visiting the mechanic when the engine seizes.
HVAC systems are complex machines with dozens of components that degrade gradually over time. Regular maintenance catches small issues — a weakening capacitor, a dirty blower wheel, low refrigerant — before they escalate into major failures. It also keeps your system running at peak efficiency, which directly impacts your monthly energy bills. Skipping maintenance doesn’t save money; it just delays — and amplifies — the cost.
Myth 3: You Only Need to Change Air Filters Once a Year
One filter change per year is not enough for most homes. Dust, pet dander, pollen, and other airborne particles accumulate quickly, and a clogged filter restricts airflow throughout your entire system.
Standard one-inch filters should be replaced every month. Thicker media filters may last two to three months, depending on your household conditions, but the guidelines from manufacturers are always worth checking. A dirty filter forces your system to work harder to pull air through, increasing energy consumption and putting unnecessary strain on the blower motor and heat exchanger. It’s one of the cheapest and most impactful maintenance tasks a homeowner can do.
Myth 4: Turning the HVAC System On and Off Saves Energy
Many homeowners assume that switching their system off when they leave and back on when they return saves electricity or gas. For HVAC, this logic doesn’t hold up.
Turning the system completely off allows your home to reach extreme temperatures — very hot in summer, very cold in winter. When you turn it back on, the system has to work at maximum capacity for an extended period to recover, consuming significantly more energy than it would have used to simply maintain a moderate temperature while you were away. A programmable or smart thermostat is a far better solution — it lets you set energy-saving setbacks automatically, without putting your system through extreme recovery cycles.
Myth 5: Closing Vents in Unused Rooms Saves Energy
This is a widespread myth that actually backfires. Your HVAC system is designed to distribute air across a specific number of vents at a specific pressure level. Closing vents doesn’t reduce the amount of air your system produces — it just has nowhere to go.
That pressure buildup stresses your ductwork, can cause leaks to develop over time, and forces your system to work harder against increased resistance. The result is reduced efficiency, potential duct damage, and uneven comfort throughout your home. If you want to control temperatures room by room, a zoning system is the right solution — not closed vents.
Myth 6: Ceiling Fans Cool the Room Temperature
Ceiling fans don’t actually lower the temperature of a room — they create a wind-chill effect that makes people in the room feel cooler. The fan cools your skin, not the air itself.
This distinction matters because running a ceiling fan in an empty room wastes electricity without any benefit. The practical takeaway: ceiling fans are a great supplement to your AC system when people are present, allowing you to raise your thermostat a few degrees without sacrificing comfort. Just remember to turn them off when you leave the room.
Myth 7: You Should Cover Your Outdoor AC Unit in Winter
Covering your condenser unit during the off-season seems protective, but it can actually cause more problems than it solves. Outdoor AC units are engineered to withstand the elements — snow, ice, and temperature swings — without a cover.
Covering the unit creates a warm, sheltered environment that attracts rodents looking for a place to nest. Mice and other small animals can cause serious damage to wiring, insulation, and internal components over a single winter. Additionally, a tightly sealed cover can trap moisture inside the unit, accelerating rust and corrosion. If you’re concerned about debris like leaves or twigs, a slatted cover over just the top of the unit is the most you’d ever need.
Get Accurate HVAC Advice From Experts You Can Trust
The best way to avoid costly HVAC mistakes is to work with a licensed professional who gives you honest information — not upsells you don’t need. At Lanz Plumbing, Heating & Cooling, we’ve been serving Urbana and the Champaign area since 2002 with transparent recommendations and reliable service.
Whether you’re due for a tune-up, shopping for a new system, or just have questions about how your equipment works, our team is here to help.
Call us at 217-394-1380 or contact us online to schedule service today.
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