A raft of new energy efficiency measures come into effect today governing household appliances ranging from smart televisions to coffee machines.
The new rules require online retailers to provide shoppers with an electronic version of the energy label already mandatory on goods bought in bricks and mortar stores.
The change is designed to make it easier for consumers to make comparisons wherever they shop.
Energy efficiency labels will also become compulsory on all domestic ovens and range hoods sold in Europe.
New coffee machines will have to switch to a low power standby or off mode after a specified time depending on the type of machine, reducing their electricity consumption by 30% or £36 over the lifetime of a drip filter model.
The measures are part of the extended Energy Labelling Directive and the EU Ecodesign Directive, which includes new rules on standby for networked appliances, commonly known as the "internet of things".
New routers, hubs, modems, connected or smart televisions and printers should be able to switch automatically into a low power standby mode if no main task is performed, saving the average household £32 a year.
European Consumer Organisation director general Monique Goyens said: "Improving the energy consumption levels of everyday consumer products is the right approach to contribute some relief to consumers from increasing energy bills.
"With purchases increasingly moving online it makes perfect sense for shoppers to have a useful energy label at their disposal to compare products."
Marylyn Haines Evans, public affairs chairwoman of the National Federation of Women's Institutes, said: "Nobody likes to waste energy, and at a time when energy bills are increasing, having appliances designed to be sparing with electricity is definitely a good thing for your household finances.
"Coffee is one of the many products threatened by climate change, so it's also good to know that when you're making a cup, you're doing your bit to cut down on carbon emissions too.
"With a better designed appliance you can enjoy a coffee without the bitter taste of wasting energy or adding unnecessarily to the climate problem."