As winter approaches in Australia, many people are , with poor heating and insulation.
Your body's ideal sleep temperature is 36.5C, which is about a 1 degree drop from the average during the day, according to sleep scientist at Flinders University Peter Catcheside.
Catcheside says this drop is significant and it means we really need to rug up.
But while we are supposed to cool down at night, too cold means your body won't be able to wind down properly, he said.
"As it gets colder and colder you'll start to shiver which prevents you from going to sleep."
"The body regulates temperature by either sending more blood to the skin to dump heat or shutting down our skin's circulation to conserve heat."
Here's what you can do to warm up at night.
First, warm yourself
Lish Fejer, an energy scientist who co-runs the energy efficiency Instagram account told SBS News that the first step is to "do what your grandparents always said" and put on some more layers.
Fejer explains that heat drains from your head, hands, and feet, in particular, so they need to be covered up and down jackets put on.
"One of the best things to do to keep yourself warm is buy an electric heated throw rug," she said.
"The heat from your heater will just leak out the windows and doors and cracks and gaps and through the ceiling. But this uses a really small amount of energy in comparison to your heater and can be much warmer."
They typically only cost "a few cents an hour" to run, Fejer said.
Next, warm your room
Fejer said eliminating draughts is essential as a draught can make you feel up to four degrees colder.
"You can be losing up to 25 per cent of your expensively heated air through gaps, cracks and leaks in your building envelope. You're basically heating the neighbourhood."
Fejer recommends using draught-proof tape, foam, clear contact, rugs or even pool noodles to insulate floors, doors and windows in both rentals and homes owned outright.
For those who aren't in a position to install double-glazed windows, taping on bubble wrap has a similar effect, she said.
“Basically, the still air in double glazing that's trapped between the layers of glass is the insulating material. So with bubble wrap, you've got all those bubbles with still air in each bubble, so if you stick it to the window it adds insulation. So that's like having a good curtain, but it's super cheap."
Source: SBS News
Chris Barnes, energy expert at comparison site CHOICE, told SBS News a reverse-cycle system which both heats and cools is by far the cheapest appliance to run.
Source: SBS News
Barnes said many people aren't aware they can use their ceiling fan to help warm up a room, because hot air rises to the ceiling.
Source: SBS News
"What you want to do is mix that warm air around the room. So your fan's reverse mode pushes it away from the ceiling back down the walls and kind of just mixes it all around the room more effectively."
Source: SBS News
Long-term tips for better heating
Those embarking on a renovation or new house build will have more scope to optimise their home for cold weather.
Barnes said, where possible, people should think about insulating their floors, walls and ceilings.
"Window coverings really make a difference as well. So having the right sort of blinds or curtains to help keep the heat in or keep the heat out in summer. All of this kind of works in reverse between summer and winter."
Fejer said during winter and summer in Australia, the importance of having north-facing windows and eaves around them can't be overstated.
"An eave is like a little verandah over your windows. It's really important that the eave is there so that when the sun is high in the sky, that eave stops the sun hitting the glass.
"Then, when the sun is lower in the sky in winter, that sun can shine underneath the eave and give you that free heating."
