"The incredible thing about Hardwick [new Hall] is… when you set it on the compass, it's almost exactly north-south," says Ranald Lawrence, a lecturer in architecture at the University of Liverpool in the UK. He's also published papers on Hardwick's design and thermal comfort. "And," he adds, "the whole internal planning of the [new] house is then based around that geometry."

Bess moved around the rooms, following the Sun's path. Her mornings were spent walking the 63m (200ft) east-facing Long Gallery, where the bright morning light hits. The afternoon and evening Sun illuminates the south-western flank of the building, where Bess' bed chambers were. And the darkest, coldest corner of the house in the north-west was where the kitchens were placed, which would have been handy in keeping food cool and fresh.

I experience this first hand as I walk around – the kitchens are much colder. Elena Williams, the senior house and collections manager at The National Trust, a UK charity which preserves historic sites, notices too. "It's a well-designed building that is also designed around comfort and that uses the natural environment to do that," she says.

It's not just the orientation that helps keep the house warm. As Williams shows me around, she points out that some of the windows on the north of the building are actually "blind" or fake. She explains that on the outside, there is a window, but on the inside, it's lined with lead and blocked up. Unlike south-facing windows, north-facing windows bring little thermal benefit, even in summer, Lawrence says.

Pretty much all the fireplaces I see are also built on the central spine of the building, meaning not much heat would be lost to the windows or exterior wall. It's not until we take a door through this spine that I realise that the girth of it is staggering – 1.37m (4.5ft) thick. This is yet another trick to keep its inhabitants warm.