pitched insulated ceilings with downlights

[dippyfrogstop]

Hi, I am currently looking at the possibility of fitting downlights into my new extension ceiling the ceiling will to be pitched to follow the line of the roof tiles, the roof rafters are 200x50 in size and to comply with building regs will need to be insulated to meet a u value of 0.18w/m2. obviously with down lights you need an air gap around the fitting which compromises the insulation at that point. does anyone know of an insulation that can be fixed to the bottom of the rafters (like a foil quilt) instaed of in between them ? are there any lights on the market that do not require air gaps around them ?
any help / suggestions would be appreciated.
tahnks in anticipation

 

[^woody^]

By definition, any insulation around the recess is going to insulate the air and keep the fitting hot

Whether the insulation goes between the rafters or on their underside (or both) is a matter of design and practicality.

You either need low heat fittings (eg CFL/Megaman/LED) or have a design which forms and air void between the insulation and the sarking membrane

You may be able to have a few spots with no insulation behind and still keep within the required overall u-value. But there may be a condensation risk with uninsulated voids

 

[noseall]

Do you really want downlights in the ceiling rake?