Edith "Hello"
 
For UV blocking windows films, an guaranty of 7 years it's good, but it's a real
 guaranty by the company ?
Whith my experience the "lifespan" of the good type of this material is approxim
ately 10 years.
After this time the efficacy is no so good (new film : 40 5W/lm, old film 100 5W
/lm !).
Elimination of the UV radiation's is not enough for a good preservation, you nee
d to reduce the visible radiation's too.
Tinted UV blocking window film it's a better solution. It's without problems for
 the color vision visitors if all windows in your building installed with the sa
me windows film.
Please send me the address of your window films company for to test there produc
ts.
 
Jean-Jacques EZRATI
lighting adviser
direction des musies de France
fax 33 1 40 15 35 00