We were excited to find dimmable GU10 LED bulbs. These ceiling lights had seemed like a good idea 20 years ago!
The new bulbs were roughly £2 each. How long might the payback time be? The old bulbs use 46.4W more. 1 kWh costs about 30p at the moment. So £2/30p = 7 kWh to 1sf. 7kWh/46.4W = 150 hours roughly. So that would be one year of half an hour a day and we will be in profit.
