The Queen will also be affected by the energy price hike with gas and electric bills at the Royal buildings expected to surge to more than £4 million, according to experts.
Regulator Ofgem announced a 54% rise on the cap on Thursday, which is set to increase energy costs for the average household by nearly £700 a year.
According to estimates, the rise from 1 April could also add millions to the cost of heating and lighting the Royal Estate.
In total, the calculations by Energy Helpline predict the Royal buildings will rack up an annual bill of £4,277,125 – rising from £2,771,158 before the cap hike.
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Buckingham Palace – which has 775 rooms covering 828,000 square feet – alone will cost an estimated £2,039,985 per year after 1 April.
Windsor Castle may cost £1,192,455 across its 100 rooms, a total of 484,000 square feet.
Other properties surveyed by the price comparison site include Althorp House, Sandringham House, Balmoral Castle and Anmer Hall.
According to estimates, the energy bill at Kensington Palace – the official residence of the Duke and Duchess of Cambridge – will cost £73,863.
This is just a shade more than Highgrove House, the private residence of Prince Charles and Camilla, which could cost £70,170.
But while the Royals can afford the rise in costs, the increase will impact around 22 million households that have already been hit by the cost of living crisis.
Scotland’s energy secretary has warned there is a "real risk" people could die in the months ahead with the country facing its highest hike in fuel bills yet.
MSP Michael Matheson said there could be up to 900,000 homes in Scotland either in fuel poverty or extreme fuel poverty due to the increases in fuel costs.
Earlier in the week, chancellor Rishi Sunak announced that all households would receive a £200 discount on bills from October, but that will have to be repaid over five years.
He said this would help reduce anxiety and take the "sting" out of the rise.
But Matheson slammed the measure, saying it would likely increase poverty due to households paying back a loan.
The price cap rise announcement has been widely held as one of the biggest hits to living standards in the UK since records began.
Customers will pay an extra £693 a year, with their costs rising from £1,277 to £1,971.
Jonathan Brearley, chief executive of Ofgem, said: "We know this rise will be extremely worrying for many people."
The Bank of England has also predicted that inflation could hit more than 7% by April.
On Friday, Ofgem gave itself the power to raise the price cap further in the next six months but bills could also go down before October if the markets allow.
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