Loop is holding 10 Summer Turn Down and Save events between July and September, with a participant's chance of winning increasing the more energy they save when compared to their normal usage.
Each winner of the 10 draws will get £200, with a 'Carbon Hero' also awarded £2,000 at the end of the scheme.
Loop is a free app that helps users save money on their energy bills by using smart meter data to flag where energy use can be lowered around the home.
Anyone with a smart meter and the app can take part, with the hour-long events held when carbon emissions are at their highest due to a lack of renewable energy availability.
Dr Steve Buckley, head of product and data science at Loop, said he wanted to help customers with the cost of electricity while also helping the environment. He said: “With wasted energy typically contributing to around 30 percent of the average energy bill, implementing these efficiency changes beyond the events can result in substantial savings.”
Loop carried out its first Turn Down and Save scheme over winter, funded by National Grid's Demand Flexibility Service, which paid more than £100,000 to Loop members using less energy when pressure on the grid was high.
Over the summer Loop wants to tackle carbon emissions, by holding events when renewables aren't producing enough electricity and polluting coal plants are used. This means the days are likely to be when it's either not sunny or windy, and typically in the morning or late evening when demand is highest.
Dr Buckley suggests customers turn all appliances off then check their smart meter display to see how much power is still being used. It may flag some forgotten electricals, such as extra televisions or fridges, or reveal high running costs of other items.
For each £200 prize draw, participants get one entry if they reduce their energy by 0-10%, with the number of entries increasing by one for every additional 10% saved, up to a maximum of five entries (for savings of more than 40%).
At the end of the summer, all entries will be totalled and added to the extra ‘Carbon Hero’ draw to win £2,000.
To enter, customers must have a smart meter and the Loop app. They will told via email about an event the night before it takes place.
After the event Loop will share a household's results and anyone reducing consumption will be entered into the draw.