Five Energy-Saving Myths That Are Quietly Costing You Money

Most of the energy tips floating around the internet are either decades out of date or were never true to begin with. They feel right because someone confident said them once, and now we all repeat them. The problem is that following the wrong advice can quietly add ten or twenty dollars to your monthly bill without you noticing. Let us walk through five of the most common myths and replace them with something more useful.

Energy myths stick around for the same reason any folk wisdom does. They sound plausible, they feel like common sense, and once your grandmother says something at the dinner table, it becomes household law. The trouble is that home appliances, lighting, and heating systems have changed enormously over the last twenty years. Advice that made sense in 1985, when a bulb pulled 60 watts and a refrigerator cycled like a tractor, often does not apply to the LED, inverter-driven, smart-thermostat world we actually live in now.

None of the myths below are silly. Each started with a kernel of truth that has since been outgrown by better technology. Following them today usually means working harder for less savings, or in some cases actively spending more money to feel like you are being thrifty. Let us go through five of the most common ones, look at where they came from, and replace them with the calmer version of the truth.

Myth #1: Leaving lights on uses less than turning them off and on

This one has remarkable staying power. You will hear it from contractors, from parents, from coworkers who swear their electrician told them so. The claim is that the surge of power when a light turns on is so large that it outweighs the savings from having it off for short periods. So you might as well leave the kitchen light on while you run upstairs for ten minutes.

The kernel of truth here is real but tiny. Old fluorescent tubes did experience a small startup surge, and frequent cycling could shorten their lifespan. For incandescent bulbs, which most homes have not used in a decade, the startup current was negligible. For modern LEDs, which now make up the lighting in most kitchens, hallways, and bedrooms, the startup draw is essentially zero. They use the same wattage at the moment of turning on as they do thirty seconds later.

A few practical numbers to anchor this:

• A 10 watt LED left on for an extra hour uses about 0.01 kilowatt-hours, or roughly 0.15 cents at average rates
• Leaving five lights on across an evening, unnecessarily, adds up to about 30 to 60 dollars per year
• Modern LEDs are rated for 25,000 to 50,000 hours of life, and switching them on and off has almost no impact on that lifespan

The simple rule is this. If you are leaving a room for more than about ten seconds, turn the light off. There is no surge to worry about, no lifespan penalty, and no hidden cost. It is one of the easiest habits to build, and it is covered alongside several others in our guide to ten low-effort habits that cut your electricity bill.

Myth #2: Phone chargers and small electronics drain serious power when plugged in

This myth has been recycled so often that entire household routines are built around it. People walk through the house at night unplugging chargers, coffee makers, and toasters, believing they are saving meaningful money. The intuition feels green and responsible, but the math does not really support it for most small electronics.

A modern phone charger left plugged in with nothing attached typically draws around 0.1 to 0.5 watts. Over a full year, that comes out to roughly 1 to 4 kilowatt-hours, or about 15 to 60 cents annually. You would have to unplug the charger every day for two decades to save the price of a sandwich. The same is true for most small kitchen appliances with simple on-off switches, like a basic toaster or a stand mixer. They draw nothing when off.

That said, there is a real version of this myth worth paying attention to. Some devices do draw meaningful standby power, sometimes called phantom load. The usual suspects include:

• Cable and satellite boxes, often pulling 15 to 30 watts even when “off”
• Older game consoles in instant-on mode, sometimes 10 to 20 watts
• Desktop computers left in sleep rather than fully shut down, often 5 to 15 watts
• Large televisions with quick-start features enabled, often 5 to 20 watts
• Anything with a glowing clock, indicator light, or remote sensor, which adds up across a whole house

Across a typical home, real phantom loads can quietly cost 80 to 200 dollars per year. The fix is not chasing every phone charger. It is identifying the few high-draw devices and putting them on a smart power strip or unplugging them when you go on vacation. Energy that flows when you are not home is a much bigger leak than the slow trickle through a charger.

Myth #3: Ceiling fans cool the room

Walk into almost any home with a ceiling fan and you will hear some version of this. “Leave the fan on, it cools the room.” Some people leave fans running in empty bedrooms all day, believing they are precooling the space for bedtime. The logic feels sound. Fan equals breeze, breeze equals cool, therefore fan equals cool room.

The reality is that ceiling fans cool people, not rooms. They work by moving air across your skin, which speeds up the evaporation of sweat and makes you feel about 3 to 5 degrees cooler than the actual air temperature. The fan motor itself adds a small amount of heat to the room, technically warming it very slightly. If no one is in the room to feel the breeze, you are paying to run a small motor for zero benefit.

A typical ceiling fan uses 15 to 75 watts depending on size and speed. Running one nonstop in an empty room costs roughly 15 to 70 dollars per year. The much better practice is to use the fan only when you are in the room, then turn it off when you leave. Pair that with raising your thermostat 2 to 4 degrees while the fan is on, and you can often save 5 to 10 percent on cooling costs without feeling any difference in comfort.

One more useful detail. Most ceiling fans have a small switch on the housing that reverses the direction of the blades. In summer, you want them spinning counterclockwise when viewed from below, which pushes air down. In winter, clockwise pulls cool air up and pushes warm air down the walls, which can make a heated room feel more even without touching the thermostat.

Myth #4: Running the dishwasher half-full saves water and energy

This one comes from a good instinct. We are taught not to waste, so running a machine half-empty feels indulgent. Many households delay running the dishwasher until it is overflowing, or worse, do dishes by hand to avoid running the machine at all. The thinking is that a fuller load is more efficient per dish, which is technically true, but the rest of the math has changed.

Modern dishwashers built in the last ten or fifteen years are remarkably efficient. A typical Energy Star model uses about 3 to 5 gallons of water per cycle and roughly 1 to 1.5 kilowatt-hours of electricity, most of which goes to heating water. Compare that to hand washing. The average person doing dishes at the sink uses 15 to 25 gallons of hot water for the same amount of dishes, and the water heater works much harder to keep up.

The practical version of this myth is more nuanced:

• Running a half-full dishwasher is still more efficient than washing the same dishes by hand
• If you have a “half load” or “eco” setting, use it for partial loads, which adjusts water and time accordingly
• Skip the pre-rinse. Modern detergents and spray arms handle food residue well, and pre-rinsing wastes 5 to 15 gallons of hot water per load
• Let dishes air dry by opening the door at the end of the cycle, which skips the heated dry stage and saves about 15 percent per load

Hand washing is not the virtuous choice it feels like. If you want to be thorough, scrape plates into the trash, load the machine fully when you can, and let it do its job. Your water heater will thank you.

Myth #5: Lowering the thermostat further makes the AC cool faster

Picture coming home on a hot afternoon to a stuffy house. You crank the thermostat down to 65, thinking the AC will work harder and cool the space faster, then you will bump it back up once you feel comfortable. It is one of the most universal household behaviors, and it does almost nothing useful.

Air conditioners do not have a turbo mode. They run at a steady output regardless of how far below the current room temperature you set the thermostat. Setting it to 65 instead of 72 does not make the system cool any faster. It just means the AC will keep running past the point where you would have been comfortable, often by 30 to 60 minutes, until it finally reaches that lower setpoint. If you forget to bump it back up, you pay for hours of unnecessary cooling.

The same logic applies to heating. Cranking the thermostat to 80 does not make the furnace warm the room faster. It just means it will keep running longer than needed. The most efficient way to cool or heat a house is to set the thermostat to your actual target temperature and let it work. A programmable or smart thermostat handles this even better, since it can pre-cool or pre-heat the house on a schedule rather than reactively.

A few related habits worth retiring:

• Closing vents in unused rooms. Modern HVAC systems are balanced for full airflow, and closing vents increases duct pressure, which can reduce overall efficiency by 5 to 10 percent and sometimes damage the system over time
• Running the AC on a much colder setting at night to “save” by turning it off during the day. Cooling a hot house from scratch typically uses more energy than maintaining a steady moderate temperature
• Blocking return vents with furniture, which starves the system of air it needs to function

If your bill suddenly jumped without any obvious change in habits, the culprit is often a thermostat setting that drifted or a system that lost efficiency over time. Our guide to troubleshooting a sudden spike in your power bill walks through the most common causes and how to track them down without guessing.

The common thread across all five myths is the same. The instincts behind them are good. We want to save energy, protect appliances, and avoid waste. But the technology underneath has changed, and the rules of thumb need to change with it. Following advice from 1985 in a 2026 home usually means working harder for smaller savings, and sometimes spending more to feel thrifty.

If you want to keep looking for quiet leaks in your monthly bill, the next place to check is the appliances themselves. A handful of small habits around the fridge, dryer, and oven can add up faster than most people expect, and our guide on five appliance mistakes quietly running up your bill covers the most common ones in plain language.

You do not have to overhaul your habits all at once. Pick one of these myths to retire this week, then come back for another next month. Small, calm changes compound, and they tend to stick because they do not feel like a sacrifice.

Frequently asked questions

Read next in Home Energy Savings

If this guide was useful, these two neighbouring pieces will fill in the surrounding context:

• Why Your Fridge May Be Your Biggest Energy Drain
• Step by Step: Tuning Your Thermostat for Savings

Sources and further reading

For the underlying data behind the numbers in this guide, and for the standards, incentive programs, and safety rules referenced throughout, see:

• ACEEE: American Council for an Energy-Efficient Economy
• DOE Building America program
• ENERGY STAR: home tips and rebates