{"product_id":"energizer-4-2w-dimmable-gls-led-bulb-e27-4000k-cool-white","title":"Energizer 4.2W Dimmable GLS LED Bulb E27 4000K Cool White","description":"\u003ch5\u003eDescription\u003c\/h5\u003e\n\u003cp\u003eThe Energizer 4.2W GLS LED bulb delivers 470 lumens of 4000K cool white light through a standard E27 Edison screw base. The bulb replaces a traditional 40W incandescent while drawing just 4.2W on 230V mains, giving the same light output at approximately 10% of the running cost. The GLS (General Lighting Service) shape matches the classic bulb form that fits most table lamps, ceiling pendants and standard light fittings without adaptor rings.\u003c\/p\u003e\n\u003cp\u003eDesigned for rooms where bright, neutral-toned light supports activity and concentration, the 4000K colour temperature sits between warm white and daylight. This makes it suitable for kitchens, home offices, bathrooms and utility rooms where task visibility matters more than ambient warmth. The bulb is fully dimmable when paired with a compatible LED dimmer switch, allowing output to be reduced from full 470-lumen brightness down to a lower evening level without flicker.\u003c\/p\u003e\n\u003cp\u003eThe bulb carries an E energy rating under the 2021 EU energy label regulations and is rated for 15,000 hours of operation, which translates to approximately 13 years at 3 hours daily use. The frosted glass envelope diffuses the LED array inside, preventing visible point sources and giving an even light distribution across the room. The cool white tone renders colours more neutrally than warm white, making it easier to distinguish detail in printed materials, food preparation and precision tasks.\u003c\/p\u003e\n\u003ch5\u003eSpecification\u003c\/h5\u003e\n\u003ctable class=\"spec_table\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eWattage\u003c\/td\u003e\n\u003ctd\u003e4.2W\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLumen\u003c\/td\u003e\n\u003ctd\u003e470lm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLamp Shape\u003c\/td\u003e\n\u003ctd\u003eGLS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLamp Base\u003c\/td\u003e\n\u003ctd\u003eE27\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEnergy Rating (New Regs)\u003c\/td\u003e\n\u003ctd\u003eE\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eKelvin\u003c\/td\u003e\n\u003ctd\u003e4,000K\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eColour Temperature\u003c\/td\u003e\n\u003ctd\u003eCool White\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimmable?\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLED or Halogen\u003c\/td\u003e\n\u003ctd\u003eLED\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch5\u003eFrequently Asked\u003c\/h5\u003e\n\u003cp\u003e\u003cstrong\u003eIs this bulb compatible with standard dimmer switches?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, the Energizer 4.2W GLS is rated as dimmable. It works with most LED-compatible dimmer switches, but older dimmer models designed only for incandescent bulbs may cause flicker or limited dimming range. If your existing dimmer is more than 10 years old, you may need to upgrade to an LED-rated dimmer for smooth operation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat's the difference between 4000K and warm white bulbs?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e4000K cool white gives a neutral, slightly blue-toned light that resembles midday overcast sky. Warm white bulbs (2700K-3000K) give a yellower, cosier tone similar to traditional incandescent bulbs. Cool white is preferred for task-focused spaces like kitchens and offices, while warm white suits living rooms and bedrooms where relaxation is the priority.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much does it cost to run compared to a 40W incandescent?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eAt UK average electricity rates of approximately 24p per kWh, a 40W incandescent bulb costs around 1p per hour to run. This 4.2W LED costs approximately 0.1p per hour, giving a 90% reduction in running cost for the same light output.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit my existing lamp shade or fixture?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe GLS shape is the standard bulb profile used in most household table lamps, ceiling pendants and wall lights designed for E27 Edison screw bulbs. The bulb diameter is approximately 60mm and the overall length is approximately 110mm, which matches traditional incandescent GLS dimensions.\u003c\/p\u003e","brand":"Energizer","offers":[{"title":"Default Title","offer_id":51783313850635,"sku":"S30642","price":1.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0729\/8993\/3835\/files\/S30642_1_475b48b3-8b0c-46b7-bcea-045c919b10c6.jpg?v=1750876531","url":"https:\/\/niori.co.uk\/products\/energizer-4-2w-dimmable-gls-led-bulb-e27-4000k-cool-white","provider":"Niori","version":"1.0","type":"link"}