Boiling a full kettle, leaving appliances on stand-by and having the heating on all year round are among the most common ways Brits are wasting money.
Researchers who carried out a detailed study found around one third of the nation ignore money saving advice and make no attempt to reduce their monthly bills.
The research of 2,000 bill-payers also revealed many of the common misconceptions around energy saving, including the fact 43 per cent believe energy-saving light bulbs have little or no impact on their bills.
It also emerged one fifth think appliances don’t use electricity in standby mode, and more than 80 per cent think power showers use less water than baths.
Ed Madden, head of marketing at npower which commissioned the research, said: “With energy, as with many other things in life, little things can have a big impact.
“A small change to your home habits may not make a massive difference alone but a few changes over a long time could not only help with your bills, but have a positive influence on the environment too.”
Additionally three quarters of those surveyed consider themselves to be conscious of their energy consumption, but 37 per cent of bill-payers admit to leaving appliances on standby.
Twenty eight per cent confess to boiling the kettle with more water than is required, 27 per cent have left lights on in empty rooms, whilst more than a fifth are guilty of falling asleep in front of the TV.
When asked to identify the biggest energy wasters in the home, a third of those polled blamed their partner, while one fifth of parents pointed the finger at their children.
Madden added: “We’re hoping that busting some of these common myths might help the nation become a little more conscious of their energy consumption.
“And there are other ways to save energy too – installing a Smart meter or seeing if you can save money by switching your tariff are easy wins.”
The study also revealed one in four Brits have been misled by common energy myths.
Npower has teamed up with Karyn Fleeting, founder of popular money-saving blog, Miss Thrifty, to uncover ways to save cash in the home.
Karyn said: “What this confirms is the UK's appetite for energy-saving advice and money-saving tips.
“For the last 10 years, I have been on a mission to help the nation save money and spend smartly.
“One thing I have discovered is that even the smallest of modifications to household habits can make a significant dent in household bills.
“One minute less in the shower every day can save you up to £80 per year. A washing-up bowl can save you up to £25 a year. It's easy money.”