A German vacuum cleaner maker is threatening to sue Dyson over allegations that it manipulated energy-efficiency tests. BSH Hausgeräte, which makes household appliances under the Bosch and Siemens brands, said it was taking steps to sue Dyson in the UK over what it said were false allegations made by billionaire founder Sir James Dyson. It did not specify what form the legal action would take. Dyson, best known for its bagless vacuum cleaners, said its lawyers were not aware of any legal claim by BSH. The threatened action is the latest skirmish between the companies over energy consumption, which has led to Dyson claiming that Bosch and Siemens had misled consumers in “behaviour akin to the Volkswagen scandal”. Sir James claimed last week that BSH cleaners had been built with electronics that allowed them to draw more power in home use than they did in laboratory tests. BSH said all its vacuum cleaners were tested in accordance with the EU energy label and ecodesign directive for vacuum cleaners and met the standards in full.

Dyson claimed that independent testing had shown that machines made by Bosch and Siemens could draw more than 1,600W of power when used in the home, despite having a rating of 750W. The UK company has sued BSH in Germany, the Netherlands and Belgium on the basis that it misleads consumers. BSH said it showed a year ago that Dyson had advertised incorrect values on energy labels for its appliances. BSH said Dyson’s claims were unfounded and untrue and that its vacuum cleaners were fitted with sensors designed to maintain suction as the bag filled up. It said this loss of suction was “one of the main challenges” for bagged cleaners and that it fitted the sensors in 2013 before the EU energy label was introduced in September last year. The legal spat between two of the biggest names in home appliances has added bite because German industry is in shock after Volkswagen admitted using defeat devices to rig emissions tests for its cars. BSH said Dyson’s claims risked linking it to the scandal at Volkswagen.

The BSH chief executive, Karsten Ottenberg, said: “We have long been aware that James Dyson has a history of taking a very aggressive approach against his competitors and has a desire to be in the public eye. With his completely unfounded accusations of cheating in the past week he has now overstepped the mark.” BSH said its bagged and bagless cleaners performed better than Dyson’s in German tests and that its machines also did better in tests by Which? best vacuum cleaner mieleThe Munich-based company said its cleaners were independently tested as well as being assessed at its research and development centre.hoover vacuum cleaner repair manualIt’ll allow us to help you faster if you ever need support.best vacuum cleaner under $200 reviews

It seems Volkswagen might not be the only German brand accused of cheating on its tests. U.K. vacuum brand, Dyson has begun legal action against German rivals Bosch and Siemens, claiming they have misled customers on the testing of their products. Dyson, famous for its bagless cleaners, claims Siemens and Bosch vacuums are using control electronics to boost their motor wattage, making them appear more competent during European Union (EU) efficiency tests. The U.K. firm claims the products in question are using a sensor that sends signals to its motor to increase its power while the machine sucks up dust remnants. However, as tests are conducted in dust-free empty labs, Dyson claims this gives an unfair reading as in a home environment, the machines use much more power. Dyson says both brands have "capitalized on loopholes" found within the EU regulations, to be granted an AAAA energy consumption rating, when domestic use shows they perform similar to that of an "E" or "F" rating.

"Consumers purchasing these machines on the basis of their widely advertised stated AAAA rating are being misled," the British company stated. Commenting on the legal action against the rival brands, British inventor and Dyson's founder, Sir James Dyson, said their behavior is akin to "the Volkswagen scandal." "Bosch has installed control electronics into some of its machines to wrongfully increase energy consumption when in use – to cheat the EU energy label," said Dyson in a statement. "Their behavior is akin to that seen in the Volkswagen scandal. This behavior is seriously misleading customers." Dyson has issued proceedings against Bosch in Netherlands and France, and against Siemens in Germany and Belgium. On top of this, Dyson is challenging the European Commission's regulations on two counts: "lab rather than living room" and "hidden costs." In a statement, the U.K. company said the current European energy label was "flawed", suggesting the regulatory board should test in both labs and homes to see the environmental differences.

On top of this manufacturers whose hoovers still require bags or filters should reveal the hidden costs of buying the "expensive, environmentally damaging, consumables." Bosch and Siemens remain firm in rejecting the claims made by Dyson. "BSH Hausgeräte GmbH (BSH Group) vehemently rejects the assertions made that consumers had been misled," BSH Group—the home appliance joint-venture between Bosch and Siemens—said in a statement. "All BSH vacuum cleaners are tested in accordance with the requirements of the EU Ecodesign Regulation for vacuum cleaners. Precise and standardized measurements have been defined by the EU for measuring the values on the Energy Label." "BSH strenuously rejects the allegations of manipulation and reserves the right to take legal action if necessary," the statement concluded. This news comes only weeks after Dyson wrote an article for The Daily Telegraph on the Volkswagen scandal and German brands, saying that regulations often offer "little more than a smokescreen for manufacturers to hide behind."