SKYLIGHTS
Low-emissivity (low-E) glass - allows light and
heat in, but reflects some of the escaping heat
back inside the room. Double glazing with low-E
glass cuts window heat loss by about 20% to
30%, compared to double glazing without low-E.
Multiple layers of good seals - to keep draughts,
moisture and noise out. The joint between the
glazing unit and the frame also needs to be well
sealed.
Spacers made of plastic or stainless steel
(instead of aluminium) - these spacers separate
the glass panes to reduce heat loss and
condensation at the glass edge.
Inert gas filling - such as argon, between the
glass layers. This is a better insulator than air,
reducing window heat loss 3% to 9% more than
double glazing with air filling.
When you choose
skylights, it’s
particularly critical to
choose ones with
good thermal
performance
characteristics to
avoid heat loss in
winter and
overheating in
summer. Apart from
the features listed in
the checklist for
double glazing, you
should consider
effective shading like
built in blinds or
shades as well as
getting an openable
skylight (for cooling in
summer). If your
skylight is installed
through a roof space,
make sure the light
shaft between the roof
and the ceiling is well
insulated.