Not sure if this a joke or a serious post, but I will take it as serious
Did you know that the Foil Bubble insulation is the same as 60mm of rockwool loft insulation, I went with acoustic 60mm rockwool in the walls, 60 mm polystyrene in the floors and roof ( I couldnt justify the cost of PIR like Kingspan or Celotex , as the cost V u Value isnt even close ) , I then double wrapped the inside ( taping the joints ) with the Foil Bubble wrap ( like your YBS )
I then ran some " super Tuff " ( its Not armoured, but its some very thick reinforced 2.5mm T&E cable ( it actually 5mm with protection, but does fit in a plug if you take a little of the protection off as it enters the plug ) cable , then fitted a Fused spur unit ( which can be upgraded to a shed consumer unit when I have the cable connected to the house consumer unit instead of a plug ) in the mancave
Then ran a series of double sockets and 2 fused spur units around the mancave ( 6 doubles and 2 FSU, one for the heater and one for a outside socket )
then I fitted one of these
https://www.screwfix.com/p/blyss-sar...te-1500w/195jk
I went with the 1500 W ( you can get 2000 W ) as its slightly cheaper to run and I can run all the power ( with this heater included ) from the 13A fixed spur unit ( as above ) as its all under 3 KW of power *( this is the important thing if running from a plug or FSU, keep all power use under 3KW, as 3KW a cheap plug top will get warm ( as FSU connection would be safer ) from my point of view, I will always aim for under 2.5 KW
I said earlier in the thread, last week it was Minus 4 C outside and I was sat in there with a hoodie and some joggers on, when I started boxing ( in VR ) I had to take the Hoodie off, this is 5 X 3 M foot print with a 2.3 M High roof , so that gives you a idea of the heat of that heater