It’s easy to believe tips passed down from friends, relatives, or the internet, especially when it comes to how you heat and cool your home. But some of the most common HVAC advice floating around is incorrect. Misunderstandings like these can lead to higher bills, less comfort, and wasted repairs. At A/C & Plumbing Doctors, we want to debunk common HVAC myths.
Closing Vents in Unused Rooms Won’t Cut Costs
It’s easy to assume that if you close the vents in a room you rarely use, your HVAC system will work less and save you money. That logic makes sense on the surface. Less space to cool or heat should mean less energy used, right? But your system wasn’t designed to guess what vents are open and what’s not. It was built to move a specific volume of air through a balanced network of ducts. When you close off vents, you disrupt that balance. Pressure builds in places it shouldn’t, and the system must push harder to move air. That extra strain can lead to leaks, a noisy operation, and higher energy use.
Closing vents in certain rooms also creates hot and cold pockets in the home, even in rooms that still have open vents. The air takes odd routes to escape, often through attic joints or small duct gaps. If a room doesn’t require conditioned air, the better solution is zoning or a ductless unit, rather than blocking vents and hoping for the best.
Bigger Systems Won’t Mean Better Comfort
It’s tempting to think that replacing your AC or furnace with a larger one will give you faster cooling and more comfort. However, the problem is that oversized systems don’t get the chance to do their job correctly. They kick on, drop the temperature quickly, then shut off before they’ve run a full cycle. That short cycling wastes energy and puts wear on the parts that turn on and off the most. It also leaves humidity behind because the system doesn’t run long enough to pull moisture from the air.
If your home feels clammy even when the temperature is cool, that could be the reason. A properly sized unit doesn’t just cool the air; it balances temperature and moisture over a full run cycle. Bigger HVACs skip that process and leave you stuck with swings in comfort. That’s why system sizing isn’t about square footage alone. Ceiling height, insulation, window placement, and duct size all affect what your house needs.
Not Every Home Works Well With High-Efficiency Systems
High-efficiency HVAC equipment sounds like a win, but your home must be able to support it. A high SEER rating doesn’t matter much if your ductwork leaks or your return vents are too small. In some cases, these systems need longer run cycles to hit their efficiency targets. That means if your space heats or cools too quickly, the system can’t reach its peak performance zone. The result is an expensive piece of equipment that works like a lower-end one.
If your home has older ducts or insulation gaps, you could lose the very savings you expected to gain. That’s not to say efficiency isn’t valuable. It is. But it only works as part of a complete setup. You need compatible infrastructure, not just the right label on the machine. Upgrading to a high-efficiency system without addressing air leaks or mismatched parts might cost you more in repairs and disappointment.
Zoning Works But It’s Not a Magic Wand
Zoning allows you to adjust temperatures in different areas of the home. But some people imagine it works like a light switch, where one room can be icy cold and another can stay warm. The reality is more subtle. Zoned HVAC setups use dampers and controls to shift airflow slightly between regions. You might be able to keep the kitchen a few degrees cooler than a bedroom, but not maintain two separate climates.
If your home has tall ceilings, large open spaces, or multiple levels, zoning can help even out comfort. But expecting it to fix massive temperature gaps isn’t realistic. Also, the design and installation matter more than the brand name. Poorly placed dampers or imprecise thermostat controls can cause one area to freeze while another never catches up. When zoning works well, it feels smooth and consistent. But it takes careful planning and regular adjustments to match what your space needs.
Thermostat Placement Is Important
Your thermostat reads the temperature in a very specific location. If that spot is near a window, above a vent, or in direct sunlight, the reading will be off. That one bad reading causes the system to turn on or off based on a false assumption. You might get uneven temperatures, short cycles, or unexplained spikes in energy use. Moving the thermostat or shielding it from drafts can often solve problems without touching the system itself.
In homes with second floors or open layouts, one thermostat may not be enough. If the unit follows what the main floor says, the upper rooms could get sticky or cold. Wireless sensors and dual-zone controls help smooth out those differences, but only if you place them correctly.
Air Filters Won’t Last Forever
You’ve probably heard you should change your air filter every three months. But that rule doesn’t work for everyone. If you have pets, allergies, or run the HVAC system constantly, your filter could clog in less than half that time. A dirty filter restricts airflow, causing the blower to work harder. That added stress can cause short cycling or even system failure if the motor overheats. You also lose air quality, which affects breathing and comfort across the house.
One way to check for a dirty filter is to hold it up to a light. If you can’t see through it, it’s time to swap it out. A clean filter helps your system breathe. If you keep forgetting to check the filter, set a calendar reminder every 30 days and glance at the filter.
AC Units Don’t Only Cool Air
Cooling systems do more than drop the temperature. They also dehumidify the air, which alters the perceived comfort of the space. You might set the thermostat to 74 degrees Fahrenheit and still feel sticky if the system isn’t removing moisture. That problem could stem from dirty coils, low refrigerant, or incorrect sizing. In dry climates, this is less of a concern. But in humid areas, dehumidification makes a big difference.
If your system cools but the house feels muggy, your equipment could be due for a check. You might not need a new system, but you could need a new approach to sizing or airflow. Air conditioning works by drawing warm air across cold coils.
Maintenance Doesn’t Have to Be Complicated
Some people avoid furnace and AC tune-ups because they seem like a hassle. However, the reality is that most systems simply require a once-a-year checkup. That checkup helps technicians catch loose parts, low refrigerant, or warning signs of wear. Small tweaks during those visits can keep the system running smoothly during the hottest weeks of summer or the coldest nights of winter.
Waiting until something breaks can leave you without air when you need it most. It also tends to cost more. Regular maintenance extends the life of the system and keeps energy bills steady.
We’ll Help You Take Care of Your HVAC
Every HVAC system has its quirks. However, when you maintain your equipment, it runs better, lasts longer, and serves your home the way it should. If you’re ready to stop guessing and get real answers, schedule a service visit with A/C & Plumbing Doctors today. We also offer air conditioning repairs, ductless mini-split installations, and smart thermostat upgrades.
