Our windows hold single glass,

Double glass all the way!! Damn make it tripple :)

I think it's draught...

In British English, draught is used primarily for (1) a current of air, (2) an animal that pulls loads, (3) a load pulled by such an animal, (4) a portion of liquid, and (5) the act of drawing liquid into the mouth. And British writers use draft for (1) a written plan or preliminary sketch, (2) an order for a bank to pay money, (3) conscription into the military, and (4) the act of selecting someone for a role. taken from here