YOU can't see it, smell it, or even taste it, but it could soon be added to Oxford swimming pools in a bid to cut heating bills.

Oxford City Council is set to test innovative liquid pool covers' to stop thousands of pounds worth of energy evaporating into thin air each year.

And although the system is not as efficient as conventional mechanical covers, climate change officers hope it will prove a cost-effective solution for unusually shaped facilities like open-air Hinksey Pool in South Oxford.

The process involves adding a special liquid - developed by the company Heatsavr - to pool water, which forms an insulating layer on the surface.

The liquid cover, just one molecule thick, does not need to be removed before the pool is used, and reforms when the water is still.

The system is being used by holiday camps including Butlins, health spa chain Champney's, David Lloyd fitness clubs, Eton College and a number of councils, including Leeds and Sheffield.

City council climate change officer Paul Spencer said the technology had been developed in North America.

He said: "It is pretty effective in keeping heat in and dramatically cuts energy bills."

Mr Spencer said using liquid covers would prove cheaper than having hard covers custom made.

Because the liquid was always in the pool, the insulating 'cover' would also form if the pool was quiet during opening hours.

He said: "You have an automatic dosing system which fits in with all your normal kit.

"After that you just pay for the liquid. It is a good system.

"It's a double whammy, really. Pool rooms have to be quite well ventilated if pool covers are not used because you get problems with condensation.

"With a pool cover you need to ventilate less."

Mr Spencer said the next step would be to test the technology at a city pool.

City council deputy leader David Rundle said the authority was committed to cutting carbon emissions.

He said: "We have been looking for some time at ways to cover our pools because of the amount of heat that is lost. We're looking at conventional and innovative solutions, both hard covers and liquid covers."

Mr Rundle said a hard cover had recently been ordered for Barton pool and was due to be installed in this month.

Council member Paul Sargent, who has lobbied for more measures to cut heat loss at city pools, said he would support any effective system.

But he added: "I am not sure people will want to go swimming in anything that has had more than chlorine added to it."