EXCLUSIVE: Why Queen Camilla and King Charles 'Constantly Battle' Over Monarch's Bedroom Habit 'That Drives Her Mad'

The King and Camilla, 78, have spent years renovating and updating royal residences, with Camilla's sister, Annabel Elliot, previously involved in a number of interior design projects for the couple.

But according to those familiar with Charles' routines, one of his strongest preferences is maintaining a cool environment – even when those around him would rather turn up the heat.

One palace aide told us: "Charles has never been someone who enjoys modern comforts simply for the sake of convenience. When it comes to sleeping arrangements, he's remarkably old-fashioned and much prefers traditional sheets and blankets over a duvet. It's one of those habits that has stayed with him throughout his life.

"He also dislikes overheated rooms and can be surprisingly stubborn about keeping windows open, even when everyone else is reaching for an extra layer. He genuinely believes fresh air is important and is happiest when his surroundings are much cooler than most people would tolerate."

According to Elliot, the difference in temperature preferences has become a familiar source of banter between the King and Queen.

She said: "There's a constant battle about it. (Charles) will have opened (a window.) (Camilla) will creep in behind and shut it. So there's a lot of, 'Oh, darling, you shut the window.' 'Yes, I have, because we're all freezing.' So a lot of banter goes on."

Another royal source stressed the disagreement Charles' bedroom preference is causing is less a serious dispute and more an example of the couple's contrasting personalities.

"Charles and Camilla have very different ideas about what constitutes a comfortable room temperature," the insider noted. "The King has always gravitated towards cool, airy spaces and loves having fresh air circulating through the house, whereas Camilla tends to prefer a warmer and more cozy environment. It's one of those small domestic differences that has followed them throughout their marriage."

The source added: "Whether they're staying at one of the royal residences in London, Scotland or the countryside, the same discussion inevitably comes up. Charles is often keen to crack open a window, while Camilla is usually the first person to point out that everyone else is shivering, and it does genuinely drive her mad at times."

The King's fondness for colder temperatures was also highlighted by former communications secretary Julian Payne, who recalled attending meetings with Charles at Birkhall in Scotland.

He said, "The King always has the windows wide open. A meeting at Birkhall, his home in the Highlands, in the middle of winter, was not for the faint-hearted. I can remember more than one occasion when I thought I might have actually got frostbite while trying to write with a hand I could no longer feel."

Another source suggested the habit reflects Charles' broader lifestyle and work routines.

The insider added, "Charles has never been the type to alter his personal habits simply because other people find them unusual. Once he settles into a routine that works for him, he tends to stick with it regardless of what anyone else thinks.

"His preference for fresh air, cooler temperatures, and working long after most people have gone to bed isn't something new. Those habits have been deeply ingrained for years and have become part of the rhythm of his daily life. They're just as much a part of him as his dedication to his work and charitable causes."

One possible explanation for the King's dislike of heavy bedding is his famously demanding schedule.

According to Lady Frederick Windsor – who is married to the King's second cousin Lord Frederick Windsor – Charles often works long into the night.

She noted: "He works all day long, has a quick supper, and then disappears until about 4 am to write letters. He cares about so many things, and he comes up with brilliant solutions."