Key Takeaways
Why Energy Myths Persist — And What They Cost You
Energy myths tend to survive because they sound plausible. They often have a kernel of logic — older technology, misremembered advice, or a half-truth passed along over time. The trouble is that acting on them can quietly inflate your utility bills month after month without any obvious sign of what's going wrong.
The hidden energy drains in most homes are rarely dramatic. They're the result of accumulated small decisions — habitual thermostat tweaks, appliances left on standby, vents closed in spare rooms. Correcting even two or three of these habits can make a measurable difference over the course of a year. The myth-and-fact pairs below address the most widespread misconceptions, with straightforward explanations of what's actually happening.
Myth
It's cheaper to leave the heating on low all day than to turn it on and off as needed.
Fact
Heating a home continuously — even at a lower temperature — uses more energy than heating it only when occupied.
The logic behind this myth seems intuitive: surely a gentle, constant warmth is less demanding than firing up a cold system? In practice, the opposite is true. Every hour your heating runs, heat escapes through walls, windows, and roofs. The longer it runs, the more energy is lost to the outside. Turning the system off — or significantly down — while you're out or asleep stops that ongoing loss. A well-timed thermostat schedule that heats the home shortly before you need it will, in most homes, cost less than continuous low-level heating. The exception may be extremely well-insulated homes where heat retention is exceptional, but for the average US home, on-demand heating wins.
Myth
You should leave lights on rather than switching them off and on, because the surge of power when turning them on costs more.
Fact
The energy used to switch on a light is negligible. Turning lights off when leaving a room saves energy.
This myth has roots in older fluorescent lighting, where frequent switching could shorten bulb lifespan. Even then, the energy spike at startup was trivially small. With modern LED bulbs — which are far more efficient and unaffected by frequent switching — there is no meaningful energy surge at startup. The only time it's genuinely not worth turning a light off is if you'll return in a matter of seconds. For any absence longer than a minute or two, switching off saves both energy and money.
Myth
Appliances on standby use virtually no electricity — it's not worth unplugging them.
Fact
Standby power, sometimes called phantom load, accumulates across multiple devices and can add a noticeable amount to annual energy bills.
Individual devices in standby may draw only a watt or two, but a typical home has dozens of devices idling simultaneously — televisions, game consoles, phone chargers, microwaves with digital displays, smart speakers, and more. Collectively, that load runs continuously, 24 hours a day. The US Department of Energy has noted that standby power can account for a meaningful share of a home's electricity use. See our explainer on standby power for a breakdown of which devices contribute most. Using power strips with switches makes it easy to cut power to clusters of devices at once.
Myth
Turning the thermostat up higher heats your home faster.
Fact
Your heating system delivers heat at the same rate regardless of the thermostat setting — a higher setting just means it runs longer.
A thermostat is a target temperature, not a speed control. Setting it to 80°F when you want 68°F doesn't accelerate warming; it simply means the system will overshoot your comfort zone before shutting off — wasting energy and often leaving you uncomfortably warm. Set the thermostat to your actual desired temperature and wait. Using a programmable or smart thermostat to pre-schedule heating ensures the home reaches comfort by the time you need it, without manual overrides that waste energy. Our comparison of smart and programmable thermostats covers which approach suits different households.
Myth
Buying energy-efficient appliances will automatically lower your energy bills.
Fact
Efficient appliances reduce energy per use, but changes in behavior — like running the dishwasher half-full or leaving the fridge door open — can offset those gains.
An Energy Star-rated appliance is genuinely more efficient than an older equivalent, but efficiency ratings assume typical use patterns. Running a high-efficiency washing machine on hot cycles, washing small loads, or leaving a new fridge door ajar can erode those savings quickly. Appliance upgrades work best when paired with mindful habits: full loads, appropriate temperature settings, and regular maintenance. The upfront cost of a new appliance also needs to be weighed honestly against projected savings — payback periods vary considerably depending on how heavily the appliance is used.
Myth
Closing vents in unused rooms reduces your heating and cooling costs.
Fact
Closing vents in a forced-air system can increase pressure imbalances and reduce overall efficiency.
Forced-air HVAC systems are designed to distribute air across a specific number of vents at a calibrated pressure. Closing vents doesn't eliminate the work your system does — it creates backpressure that can strain the blower motor, promote duct leaks, and cause the system to cycle less efficiently. In some setups, it can also push conditioned air into unconditioned spaces like attics or crawlspaces. If you want to reduce heating or cooling in specific rooms, a zoned system or mini-split is a more effective approach — though those involve significant upfront cost. For lower-cost adjustments, see our guide to low-cost heating bill reductions.
Putting the Evidence Into Practice
Clearing up these myths isn't just an intellectual exercise — each correction points toward a concrete behavior change. Schedule your heating rather than leaving it on low. Switch off lights when leaving a room. Use a power strip to cut standby loads. Set your thermostat to the temperature you actually want, not higher. Run appliances with full loads and appropriate settings.
None of these changes require spending money. For homeowners who want to go further, there are low-cost measures that can make a noticeable difference to heating bills — from draught excluders to radiator reflector panels. And if you're still unsure where your energy is actually going, a complete home energy efficiency overview can help you identify where to focus first.
Don't Confuse Efficiency With Automatic Savings
Upgrading to efficient appliances or equipment is a positive step, but it doesn't guarantee lower bills on its own. Usage habits, occupancy patterns, and home insulation levels all play a role. Calculate realistic payback periods before making significant purchases, and don't assume the savings will materialize without also reviewing how you use the equipment.
This article provides general educational information about home energy use. It does not constitute professional energy audit advice. For a detailed assessment of your home's energy performance, consider consulting a qualified energy auditor or contacting your utility provider about available programs.