Left out in the cold...

[shlondon2020]

Hoping for some friendly advice for somebody who isn't particularly clued up.

I've just bought my first home, a small 40sq m apartment, 1 bedroom in London.
I'm on the top floor (2nd) and on the end so one side of the flat has external facing walls. Lived here 3 months now.

The rooms with external walls to the flat, bedroom and bathroom, are both extremely cold. If I leave the heating off for the day, it sits at 13 degrees during winter months. If I put the heating on, it takes several hours to reach the top of about 18/19 degrees and then will drop again throughout the night to 13 degrees.

I've pushed the developer to check the insulation but they are refusing so just hit a dead end. I'm engaging my building insurance company for their advice.

Is there a standard in terms of temperature that new builds should be at?

Long story short, the room with external walls cannot retain heat. Developer refusing to help. Any advice?

[shlondon2020]

Also to add, I have requested the air leakage tests although I'm not going to have any idea what I'm looking at. I'm also aware these get cheated sometimes by developers.

[New Home Expert]

Who is your housebuilder?

"Sometimes!"  Air leakage tests get fiddled all the time if the new home fails!

You need to get a thermal survey for your home as well as an independent air leakage test.
You will then know where to cold is getting in and the heat is getting out.
With this information and proof you should be able to force the builder/warranty provider to act!

All new homes have minimum temperatures for certain rooms.
Lounge & dining room  21 deg C
Bathroom 22 deg C
Hall, Kitchen, Bedrooms, Toilet 18 deg C

Finally, if the walls are cold I am surprised you haven't got a serious mould problem.
Be sure to position furniture away from walls so the air can circulate.
Next excuse the builder will say it is "caused by your lifestyle" drying clothers indoors, no ventilation, not using extract fans etc.