Bagless-vacuum cleaner manufacturer Dyson is awaiting a European court verdict on changes to the energy labelling system for appliances.
The company recently appealed to change the current rules which it says are misleading to consumers.
It says that current energy ratings are derived from tests where the device is empty of dust. This can lead to hoovers being given unrealistic ratings as they use significantly more power when they are full.
A European court verdict on the rating system is expected to be delivered on Wednesday.
Last month, Dyson accused rival vacuum cleaner manufacturers Siemens and Bosch of misrepresenting the power consumption of their models to consumers, which it said increased dramatically with the amount of dust drawn.
It claimed that independent testing had shown that machines made by them could draw more than 1600W of power when used in the home while containing dust despite having a rating of 750W gained in dust-free testing.
Siemens and Bosch later announced they were taking legal action against Dyson for its accusations.
Sir James Dyson, founder of the company said: "People want high performing technology which uses less energy and materials.
“A good energy label for vacuum cleaners would guide them to these machines, but in its current form it does not show the true 'in-use' energy consumption and performance of a machine since the testing is done with no dust - hardly representative of your living room.
"As a result it can mislead consumers on the real environmental impact of the machine they are buying - particularly with bagged machines which lose suction as they fill with dust - and it gives manufacturers room to engineer machines which gives beneficial results in the lab, but different ones in the home."
Dyson has claimed that machines with a rating as high as AAAA in test conditions could drop to an E or F in realistic conditions in the home.
The EU has already proposed reforms to energy labelling rules in the form of a single scale from A to G and a digital database for new energy efficient products.
It says the proposal is in line with making the EU energy system more sustainable via well-informed consumer choices.
Last year, Dyson launched a vacuum cleaner with the promise that it would not lose any suction for 10 years (pictured).