A new website has been launched which will give an idea about the amount of CO2 being emitted to heat water in UK homes.
Produced by the Energy Saving Trust (EST), it also suggests ways for users to save water and energy, as well as cutting their carbon footprint.
According to the Trust, CO2 from energy used to heat water in UK homes accounts for 5 percent of the nation's total carbon emissions.
Still, it adds, water use is the "forgotten energy saving opportunity" by homes, businesses and policymakers.
The EST produced the calculator as an interactive, "easy to understand" tool for people to make the link between water efficiency and energy efficiency, said Andrew Tucker, EST's water strategy manager.
Energy used in the UK water sector accounts for about 6pct of the nation's total CO2 emissions, 89pct of which is a result of homes and businesses heating the water.
According to figures from the Trust, it is estimated that heating water accounts for about 30pct of the average household's energy bills.
"Generally, people are generally aware of energy efficiency, but when it comes to water efficiency, it is looked at as a separate issue," the BBC quoted Tucker as saying.
The calculator provides each user with a personalised report that tells them how much water their household uses, the related carbon emissions and the cost of the water and energy used.
The report, said Tucker, also offers a series of tips that can help reduce the amount of water and energy consumed.
"For example, it will say that if you took a minute off the time you spend in the shower then you could save 'x' amount.
"The fastest growing water use in UK homes is our changing shower behaviour; we are taking longer and longer showers.
"That is costing us in money, water and carbon," he added.