Every winter, Central Indiana homeowners unknowingly waste hundreds of dollars on heating costs. The culprit? Well-intentioned but misguided HVAC decisions that seem logical on the surface but actually work against your system’s efficiency.
These mistakes are so common that HVAC professionals see them daily. The good news is that once you understand why these approaches backfire, you can make smarter choices that keep your home comfortable while reducing energy waste. Let’s explore three of the most expensive HVAC mistakes—and what to do instead.
Mistake #1: Closing Vents in Unused Rooms to “Save Money”
This seems like common sense, right? If nobody’s using the guest bedroom or home office during the day, why heat it? Close the vents, reduce the area you’re heating, and save money.
Unfortunately, your HVAC system doesn’t work that way.
Why This Backfires
Your furnace and ductwork were designed as a balanced system. When you close vents, you don’t reduce the amount of air your furnace produces—you just increase the pressure in the remaining ducts. This creates several problems:
Increased pressure stresses your ductwork. Your ducts weren’t built to handle this extra pressure. Over time, seams can separate and connections can loosen, creating leaks that waste heated air in your attic, crawlspace, or walls—areas you definitely don’t want to heat.
Your furnace works harder, not smarter. Modern furnaces have sensors that detect airflow. When you reduce airflow by closing vents, your system compensates by running longer to try to move the air it’s designed to move. This means more runtime, higher energy bills, and increased wear on components.
Temperature imbalances trigger longer cycles. If you’ve closed vents in bedrooms but your thermostat is in the hallway, your furnace keeps running until that hallway reaches the set temperature—which takes longer when airflow is restricted. Meanwhile, the rooms with open vents get overheated.
Many Carmel and Fishers homes have two-story layouts where homeowners close upstairs vents, thinking they’ll save money since heat rises anyway. Instead, they create pressure problems that can damage ductwork and reduce overall system efficiency by 20% or more.
What to Do Instead
Keep all vents open and consider a zoning system if you genuinely want to heat different areas differently. A zoned system uses dampers inside your ductwork (not at the vents) and multiple thermostats to control temperature by area without creating harmful pressure imbalances.
If certain rooms are consistently too warm or too cold, the issue isn’t about closing vents—it’s about airflow balance, insulation, or ductwork design. A professional assessment can identify the real problem and provide solutions that work with your system, not against it.
Mistake #2: Ignoring Where Your Thermostat Lives
Your thermostat is essentially the brain of your HVAC system, telling your furnace when to heat and when to rest. But if that brain is getting false information about your home’s actual temperature, it makes poor decisions that cost you money.
Why Thermostat Placement Matters
Walk through many Central Indiana homes and you’ll find thermostats in problematic locations:
Near drafty windows or exterior doors where cold air infiltration makes the thermostat think the whole house is colder than it actually is, triggering unnecessary heating cycles.
In direct sunlight where afternoon sun makes the thermostat think your home is warmer than reality, leaving you shivering in other rooms while the furnace stays off.
In the kitchen where cooking heat creates false warm readings, or near bathrooms where shower steam affects humidity sensors in smart thermostats.
In hallways near supply vents where the thermostat gets blasted with warm air directly from the furnace, making it think the house has heated up faster than it actually has, resulting in short cycling.
This is particularly problematic in older Noblesville homes where thermostats were often installed based on convenience during original construction rather than optimal placement for accurate readings.
The Real Cost
Poor thermostat placement can increase your heating costs by 10-15% without you realizing it. Your furnace runs when it doesn’t need to, or doesn’t run when it should. Rooms become uncomfortable, and you keep adjusting the temperature up or down, creating even more inefficiency.
Smart thermostats with remote sensors can help, but they’re not a complete fix if your main thermostat is in a terrible location.
What to Do Instead
Your thermostat should be:
- On an interior wall, away from exterior doors and windows
- Out of direct sunlight
- Away from heat sources like lamps, appliances, or supply vents
- In a room you use frequently (not a guest room or hallway you rarely enter)
- About five feet off the floor, where it measures air temperature at the level where you actually spend your time
If your current thermostat is poorly located, relocating it is usually straightforward and pays for itself quickly through improved efficiency. A professional can assess whether your current location is causing problems and recommend the ideal spot based on your home’s layout.
Mistake #3: Waiting Until Complete Failure to Call for Service
Of all the HVAC mistakes homeowners make, this one is the most expensive. Many Central Indiana residents view their furnace like their refrigerator—something that should just work until it doesn’t, at which point you call for repairs.
But furnaces aren’t appliances you can ignore. They’re complex systems with moving parts, combustion processes, and safety mechanisms that require regular attention.
The True Cost of “Run It Till It Dies”
When you wait for complete failure, several expensive things happen:
Emergency rates apply. Furnace breakdowns don’t happen on convenient Tuesday afternoons—they happen at 2 AM on the coldest night of January when demand for HVAC services peaks. Emergency service calls cost significantly more than scheduled maintenance.
Minor problems become major expenses. A dirty flame sensor that would cost $150 to clean and adjust during maintenance becomes a $600 repair when it causes your furnace to shut down completely and stresses other components in the process.
Efficiency drops long before failure. A furnace that’s limping along with worn parts might use 25% more energy than necessary for months before it finally quits. That’s money literally burning up while you’re unaware there’s even a problem.
Shortened equipment lifespan. A well-maintained furnace lasts 15-20 years. One that’s neglected might only make it 10-12 years. When a furnace replacement costs $3,000-$6,000, those extra years matter significantly.
Indiana’s temperature swings are particularly brutal on HVAC systems. When we go from 50 degrees to 10 degrees overnight, your furnace experiences thermal stress that accelerates wear. Without maintenance, these stresses compound faster.
What to Do Instead
Schedule annual maintenance every fall, before heating season begins. A thorough maintenance visit includes:
- Cleaning and inspecting the heat exchanger
- Testing and adjusting the burner for optimal combustion
- Checking all electrical connections
- Lubricating moving parts
- Testing safety mechanisms
- Cleaning or replacing filters
- Measuring temperature differentials to ensure proper heating
- Identifying worn parts before they fail
Most importantly, a technician can spot warning signs you’d never notice—slight discoloration indicating incomplete combustion, unusual wear patterns suggesting alignment issues, or efficiency drops that show up in diagnostic readings but not in obvious symptoms.
The cost of annual maintenance ($100-200) is far less than the cost of emergency repairs ($400-1,000+) or the energy waste from declining efficiency ($200-400 per winter).
The Bottom Line: Small Changes, Big Savings
These three mistakes—closing vents, ignoring thermostat placement, and skipping maintenance—represent the most common ways Hoosier homeowners waste money on heating. The good news is that correcting them doesn’t require huge investments.
Keep your vents open, assess your thermostat location, and schedule annual maintenance. These simple steps can reduce your heating costs by 20-30% while extending your equipment’s lifespan and preventing inconvenient breakdowns.
Your HVAC system is one of the largest energy consumers in your home. Treating it with proper care and understanding how it actually works pays dividends every winter—not just in lower bills, but in consistent comfort and peace of mind when temperatures plunge.