They are, by all accounts, wheels to die for. JP Ward & Sons, an Irish funeral services home, rents out its fleet of Mercedes E-Class limousines not just to mourners but to anyone who wants to travel in style.

A killer price tag has not deterred the latest customer: the White House. It is so keen to use the vehicles for Donald Trump’s two-day visit to Ireland that it is spending nearly $1m (£788,000) of US taxpayers’ money to rent them.

The Trump administration paid the family-owned firm based in Bray, County Wicklow, $935,033 in four tranches, according to USASpending.gov, an official portal that records federal government spending.

The state department did not immediately respond to a request for confirmation that the outlay was to rent four vehicles, which would work out at $233,748 per vehicle.

The presidential entourage’s hotel bills have also drawn scrutiny. State department documents show US taxpayers have spent $1,223,230 on VIP accommodation at the InterContinental hotel on Park Lane in Mayfair, London.

After wrapping up a state visit to Britain, Trump is to fly into Shannon airport in County Clare on Wednesday evening. He will meet the Irish taoiseach, Leo Varadkar, and then fly by helicopter to his golf resort in Doonbeg, which overlooks the Atlantic.

He will fly to Normandy for D-day commemorations on Thursday, then return to Doonbeg for another night and a round of golf. He returns to Washington on Friday.

Exactly why the president needs the limousines is unclear. If Trump, his wife, Melania, and other senior members of the entourage travel by helicopter, they may have no need of cars.

If they visit the village of Doonbeg, as locals fervently hope, it will be an eight-mile round trip at a combined cost of $116,879 per mile, excluding the additional bill for the rest of the entourage, possibly in dozens of vehicles.

The company address advertised on the website of JP Ward & Sons in Bray, County Wicklow. Photograph: Rory Carroll/The Guardian

JP Ward & Sons could shed no light on the arrangements. A woman who answered the company’s advertised phone number on Thursday said she knew nothing about leasing vehicles to the US president. She said a colleague would phone back. Repeated further calls and an email went unanswered.

If discretion is part of the company’s business model, it seems to work. When the Guardian visited the company’s advertised address in Bray, a seaside town south of Dublin, it turned out to be a terraced house with an overgrown front garden and no indication that it was a business. Nobody answered the door.

One neighbour said Philip Ward, the company owner, stored cars at a different location, but when the Guardian visited there was no sign of life.

In June 2013 the company reportedly earned $114,000 ferrying Michelle Obama and her daughters Sasha and Malia around Dublin and Wicklow for three days while Barack Obama attended a G8 summit in Northern Ireland.

The first lady rode in one car and her daughters in another, said George McClafferty, who guided them around Glendalough. “There were 35 cars in the entourage,” he said.

The funeral company’s website says it has invested heavily in state-of-the-art hearses and luxurious limousines. “Your comfort and safety are our number one priority. All our vehicles are driven by professional, discreet and fully uniformed drivers.”

Organisers of Trump’s trips were particular about vehicles even before he became president. During his fleeting visit to see his mother’s birthplace in Stornoway, Scotland, in 2008, Trump used the only black Porsche Cayenne four-wheel drive available on the Isle of Lewis, which the Trump Organization had borrowed off a local businessman after days of searching.

Trump insisted on hiring black Range Rovers for his sporadic visits to Aberdeenshire, including his trip to receive an honorary degree from Robert Gordon University in 2010 – an honour rescinded by the university in 2015 after Trump’s insults against Muslims and Mexican migrants.