In this article, we go through how to fit lights, downlighters, recessed lights or spotlights into our insulation safely and securely.
Can spotlights be fitted in Kingspan insulation products?
As a result of their thermal performance, if you were to place a downlight or spotlight directly into the insulation products, the heat generated by the lighting would not be able to dissipate. The following guidance explains best practice and some of the precautions that should be taken.
Manufacturers and building warranty providers
Tip 1: In the first instance you should contact the manufacturer of the lighting unit who will offer specific guidance for their spotlights and downlighters as excessive heat may affect the performance of that light.
Tip 2: It may also be worth consulting the building warranty providers to check if they have any additional requirements which need to be complied with.
Options for fitting lights in insulation in the absence of manufacturers guidance
Option 1: Create a false ceiling
In order to prevent penetrating the insulation to recess light fittings, you can create a ‘service void’ or a false ceiling in effect below the insulation. The depth of this services void and the necessary clear space will have to be determined by the lighting manufacturer.
This can be a good option as you will not penetrate the insulation or the inbuilt vapour control. Also you may get a benefit as the void could be deemed as a low emissivity air space – potentially meaning less insulation is needed.
Option 2: Install lights on ceiling with insulation
If you are placing the lighting unit into the insulation, a rule of thumb is to cut a hole in the insulation twice the diameter of the light fitting. Mount the light fitting to the plasterboard as you would normally. Maintain a clear air space around the light fitting, according to the manufacturer’s instructions.
To avoid warm, moist air being drawn into the roof space and potentially risking rot as well as clearly losing energy, an intumescent or fireproof ‘hat’ needs to be placed over the light fitting – taking care to maintain the clear space required (search online for ‘Downlight Covers’ for manufacturers of these). Insulation can then be placed over this to avoid heat loss. Many lighting manufacturers will have their own products to solve this problem.
You should also be aware of the implications of electrical cables, as the cables to supply recessed fittings will often be either fully or partially buried within the insulation and therefore some extra care needs to be taken. The effect is that the insulation could reduce the load-carrying capacity of that cable which may have to be increased in size to safely carry the load. The following should be considered:
• Circuits run within thermal insulation must be protected with cartridge fuses or mini circuit-breakers (MCBs). Rewireable fuses are not suitable.
• Cables fully enclosed by insulation may need to be increased in size above the standard recommended size by as much as 20% if they pass at right angles through an insulating layer, and as much as 50% if they are enclosed along their length for more than 500 mm.
• For cables enclosed by insulation but in contact with a thermally conductive surface on one side, the larger of the standard recommended sizes will generally need to be used.
Detailed information can be found in BS 7671: 2018 + A2: 2022.
