Forgetting to turn off lights when leaving a room is a common point of contention in many households. One side views leaving lights on as wasteful, while the other argues that frequent switching on and off damages bulbs quickly.

In fact, the advice to "always turn off lights when not in use" was truly accurate only during the era of incandescent bulbs, an inefficient type of bulb that converted most of its energy consumption into heat.

Today, with modern light bulbs, energy consumption is minimal. According to Jon Chase, a smart home device expert at Wirecutter, the principle of energy saving is sound, but its impact on current technology is limited.

According to calculations from the US Department of Energy (DOE), an 8,8W LED bulb (equivalent to a 60W incandescent bulb) continuously on for one hour consumes only 0,0088 kWh. With current electricity prices in Vietnam, keeping this bulb lit for 20 hours only costs over VND 300. While turning off LED lights reduces electricity consumption, the energy saved is insignificant.

"You can light dozens of LED bulbs 24/7, and they will still consume less energy than one refrigerator uses in one day", Chase said.

Turning off lights no longer holds much significance with the current popularity of LED lighting. Photo: Nytimes

Concerning lifespan, frequent switching does not damage LED bulbs. LED lighting technology differs from incandescent bulbs; components do not suffer thermal or physical shock when the current changes. Therefore, the frequency of switching on and off does not affect the bulb's durability.

However, the story is entirely different if your household uses compact fluorescent lamps (CFLs), a type commonly found in older buildings. The lifespan of CFL bulbs is significantly shortened if they are switched on and off frequently. For these lights, the DOE advises users to apply the "15-minute rule": If you leave a room and return within less than 15 minutes, leave the light on. If you are gone longer, turn it off.

Today, many households are switching to smart bulbs to automate lighting. While convenient, this technology encounters the issue of "vampire power". To be ready to receive commands from an app or voice, devices must maintain a continuous Wi-Fi connection. This standby state consumes about 0,2W to 0,5W per bulb. While this figure is small, if one house installs dozens of smart bulbs and keeps them plugged in 24/7, the cumulative power drain over a year can amount to a considerable cost.

Bao Nhien (According to Wirecutter)