Riddle me this: hot room in house

[SilverHairedCat]

The main bedroom in our house is boiling. We are the type of people who rarely have the heating on in winter and the bedroom window is open all day and night in all weather. I can't explain why this room gets so hot. Can you help?

The attached floor plans are of our mid-terrace house. The neighbours either side have an identical layout.

Bedroom 1 is our room, it's north facing, and boiling hot.
Bedroom 2 is the spare room and south facing. It's lovely and cool.

All rooms in the house are painted matt white and have wooden floors. Only the hall / stairs have carpet. I like minimalist with accent colours!

I cannot with out what's going on. Can anyone help? DH had taken to sleeping in the other room....

Ah ok, so the boiler is on. Where is the boiler?

@FrangipaniBlue yes to open stairs - will try closing the door today and see if that helps.

No down lights, just normal pendants - one in the living room area, one in the dining room area.

Boiler is still in the kitchen. I can see and hear when it is fired up. It is not fired up unless the hot water is running for the kitchen or bathroom sink, as we don't use the bath and the shower is an electric one.

What kind of lightbulbs?
We have changed to LED bulbs everywhere except the downstairs loo. I really notice the heat from the bulbs in their.

Normal bulbs, they are pendant lights, no LED options.

And thinking about it, we mostly use the freestanding uplighters dotted about the room, rarely the over head lights (I prefer diffuse light) l.

Odd. Insulated roof above your room and not the back? Seems unlikely though!

Will check the insulation in the loft actually, thank you.

You can get LED bulbs for any kind of light fitting.

Check your meters. How many kWh per day are you currently using, and how many cu.m of gas?

also, buy a few cheap thermometers. Put one on the ceiling of the room beneath your bedroom, put one under your bed, put one on each of the neighbours' walls.

It's very possible that the sun is beating through the windows of the room below, and the heat is easily passing through the ceiling and up into your room. Carpet and underlay slow it down. If this is the actual problem, and there are no holes in the ceiling (usually for pipes and downlighters) then it's possible, though a bit dusty, to take up the floor and pack loft insulation between the joists. This also muffles sound a little bit.

Open plan is also bad for hot air rushing upstairs.

Open your loft hatch, and the warm air will rush up there and escape through the eaves. You will actually notice it blowing if you open a downstairs door or window.

Check your loft insulation. At this time of year lofts get unbearably hot from the sun beating on the tiles. I haven't had an uninsulated house for many years so I don't know to what extent it can radiate downwards, but loft insulation will stop it.

I only use Mineral Wool treated with Ecose to prevent irritant dust. Expanded foam slabs are a very good insulator, but since Grenfell I wouldn't have them in my house, unless encased in a cavity wall.

"freestanding uplighters "

Do you mean the one with 300W or 500W halogen lamps? That get scorching hot?

www.screwfix.com/p/diall-r7s-linear-halogen-light-bulb-8550lm-400w-118mm/9372k

As PJ says check your loft insulation maybe it's insulated above the back bedroom but not above yours as the heat from the roof heated by the sun can be considerable.