Because HVAC systems are standard in most modern households, there’s no shortage of advice and opinions about how they work. Unfortunately, not everything you read or hear is true. Below, we’re addressing some of the most common myths so you can make informed decisions about your heating and cooling system.

Myth: Setting a Lower Temperature Cools Your Home Faster

When you come in from the heat and your home feels warm, it’s tempting to crank the thermostat down to the lowest setting, thinking it will cool faster. The reality is that most residential air conditioners cool at a fixed rate, so lowering the setpoint doesn’t speed things up — it just makes the unit run longer until it reaches that temperature. The best approach is to set your thermostat to your desired comfort level and let the system work steadily.

Myth: Air Filters Only Need to Be Changed Once a Year

Waiting a full year to replace your air filter can reduce airflow, increase wear on your HVAC system, and hurt indoor air quality. Most homes need a filter change every 1–3 months. Homes with pets, allergy sufferers, or high dust levels may need more frequent replacements. A good rule of thumb is to check your filter monthly — if it looks dirty or you can’t see light through it, replace it.

Myth: Bigger is Always Better

An oversized HVAC unit can short-cycle (turn on and off too frequently), leading to higher energy bills, poor humidity control, and premature wear. On the other hand, a unit that’s too small will struggle to keep up, running constantly and wearing out faster. The key is proper sizing. Our technicians perform a professional load calculation — factoring in square footage, insulation, windows, and occupancy — to recommend the right size for your home.

Myth: Closing Vents in Unused Rooms Saves Money

It might seem logical to close vents in rooms you’re not using, but doing so can create an imbalance in your duct system. This increases air pressure, which can cause duct leaks, stress your blower motor, and reduce overall efficiency. Instead of shutting vents, consider a zoned HVAC system designed to control temperatures in specific areas without overworking your equipment.

Myth: Routine Maintenance is Optional

Skipping maintenance may save you money now, but it can cost you in the long run. Many manufacturer warranties require at least one professional maintenance visit per year to stay valid. Regular tune-ups improve efficiency, extend equipment life, and catch small problems before they become costly repairs. In some cases, a twice-yearly schedule (once before cooling season, once before heating season) is recommended.

Myth: Running the Blower Fan After Cooling Saves Energy

Most thermostats allow you to run your blower fan without heating or cooling. While this can help circulate air, in humid climates it can also reintroduce moisture into the air. When your AC runs, moisture collects on the evaporator coil and drips into a drain pan. If you immediately switch to fan-only mode, the blower can push that moisture back into your home, making it feel clammy. In dry climates, this effect is less noticeable, but running the fan continuously still uses extra electricity and can move dust through your ducts if they aren’t clean.

Myth: Refrigerant “Runs Out” Over Time

Your AC’s refrigerant is part of a sealed system — it doesn’t get used up like fuel. If your refrigerant is low, it means there’s a leak somewhere in the system. Simply adding more without repairing the leak will only lead to repeat issues. Our technicians can locate and fix leaks before recharging your system to restore cooling performance.

Myth: Run Your HVAC Until It Fails

While it’s natural to want to get the most out of your investment, running your system until it breaks down can leave you without heating or cooling at the worst time — and force you into an emergency replacement. The average central AC lasts about 12–15 years (sometimes longer in mild climates, shorter in extreme heat or coastal areas). After a certain point, older systems lose efficiency, resulting in higher operating costs. Planning a replacement before total failure allows you to choose the right unit, schedule installation at a convenient time, and avoid costly rush decisions.

Exceptional HVAC Service in Southeastern WI

At One Hour Heating & Air Conditioning®, we size, install, maintain, and repair HVAC systems to keep your home comfortable year-round. Whether you need a tune-up, a repair, or help choosing a new system, our team is here to make sure you have the right solution for your home. Call today to schedule your next service.