Do these coated windows reflect RF or attenuate. My guess yes. Im thinking
in terms of wifi.
These can be quite problematic.
One thing to try is some passive antenna systems.
Install an outdoor antenna outside the house (preferably at the top of
the top of the building). Use a low loss (at 2.4 GHz) coaxial cable
to bring the signal into the room where it is needed. Use a
omnidirectional antenna to re-radiate the signal to the handset in the
room (preferably not more than 1-2 m from the re-radiation antenna).
Passive antenna systems are usually OK anywhere in the world. Anything
requiring active RF amplification are typically under the control of
local telecommunication authorities (except WLAN frequencies).
Using outdoor WiFi access points, Ethernet cables through the wall
into a building and another WiFi AP inside the building might also be
OK.