The Insect Killer Lamp uses ultraviolet rays of specific wavelengths (usually 365-400nm) in combination with high-voltage power grids to kill pests, but its core efficacy faces severe challenges during the day. The primary limiting factors are the powerful spectral coverage of sunlight and the intensity of ambient light. The solar radiation power density at noon can reach over 1000W/m², and its spectrum contains high-intensity and full-range visible light and ultraviolet rays (UVA intensity can reach approximately 30-50 W/m²). In contrast, the intensity of the insect-attracting ultraviolet light emitted by Insect Killer lamps (such as the common 20W model) is typically only about 30-50 μW/cm² (i.e., 0.3-0.5 W/m²) at a distance of 1 meter from the device, showing an intensity disadvantage of up to 100,000 times. Make its light almost undetectable by the target insects during the day. An environmental study on the phototaxis of flies in 2018 found that under an environmental illuminance of over 10,000 lux (easily reaching 30,000-100,000 lux during an ordinary day), the attractiveness of Insect Killer lamps to target insects dropped sharply by more than 90% compared to at night.
Secondly, the activity patterns of most target pests (such as mosquitoes, flies and moths) during the day are significantly weakened or changed. This is closely related to the biological clock and environmental adaptation of insects. For instance, the activity of houseflies during the day usually drops by 50% to 70%. Many phototactic moths themselves are nocturnal species and are basically inactive during the day. At this time, when the Insect Killer Lamp is turned on, even if it operates with power consumption (a single unit consumes approximately 0.24 kWh of power for 12 hours during the day), the killing efficiency of its high-voltage power grid is nearly “idle”. A farm pest management case in 2020 showed that when multiple Insect Killer lamps were continuously turned on during the well-lit day, only 3%-5% of the total insects captured at night were captured. The number of insects killed decreased by approximately 95-97%, and the power utilization rate was far lower than the peak efficiency range. In other words, more than 95% of the daytime operating time and power consumption cannot be translated into effective pest control benefits.
From the perspectives of operating costs and equipment lifespan, unnecessary daytime operation is also not a wise choice. Take the Insect Killer Lamp with an average power of 20W as an example. It consumes approximately 0.24 kilowatt-hours of electricity when running continuously for 12 hours. If the retail electricity price is calculated at 0.8 yuan per kilowatt-hour, the daily operating cost per unit is approximately 0.19 yuan, and the cumulative annual cost is about 70 yuan. For restaurants or farms that have deployed 10 devices, this redundant expense exceeds 700 yuan. In addition, the lifespan of ultraviolet lamps is typically around 8,000 to 10,000 hours. Unnecessary daytime use will significantly shorten their effective service time (if they operate for 12 hours throughout the year, the lifespan will be reduced by approximately 25% to 30%), directly increasing the replacement cycle and frequency of consumables (for example, from the theoretical 3 years to about 2.2 years). The usage cost per unit time has increased by approximately 12%, and the overall benefits and resource utilization rate are far lower than those of the optimized usage strategy.
Although the Insect Killer Lamp performs poorly during the day, it is still an excellent tool for pest control at night, especially when deployed in the correct position and activated on schedule (from dusk to the next morning). Users can set a timer (with an investment of approximately 20 to 50 yuan) to automatically turn on for about 10 hours after sunset and turn off before sunrise. A 2022 study on home environmental control found that households following the night-time operation strategy achieved up to 70% energy savings compared to those operating 24 hours a day. The effective insect capture rate at night exceeded 95%, and the daily power consumption per unit dropped to only 0.08 yuan, with a cost efficiency improvement of nearly 400%. This clearly shows that the design of Insect Killer Lamp naturally matches the specific environmental conditions at night with its efficient application logic, and daytime operation is not a reasonable choice in the face of scientific evidence.