There ARE different types of tint, above and beyond the different 'shades'.
There's dye-based tint, metallic tint and ceramic tint. -Metallic reflects the light best of all and results in slightly cooler interior temperatures on hot days. -May not be so much of an issue for much of the year in the UK, but in Florida that's a BIG difference; -specially in the summer.
However, the metallic tint also acts as an attenuator for radio frequency signals, and many people have reported lower signal strength on things like mobile phones, portable navigation systems, etc. -If your signal strength where you live is marginal, a metallic window tint may mean more dropped calls.
Dye tint is the cheapest (and is most likely what 'Chavfords' sells) but often 'fades' over time with strong sunlight, and also may brands tend to 'wash out' if you use window cleaner on them. -Most should ONLY be cleaned with water, since even dilute solutions of ammonia, or vinegar, or 'windowlene' will wash out the tint. Metallic film is
usually pretty immune to cleaning chemicals.
Ceramic tint film is more expensive than dye, and usually SLIGHTLY more expensive than metallic. -It has the advantage of not attenuating radio waves in the same way that metallic does, and it holds up to cleaning products very well indeed.
So if you WANT the 'shiny' metallic look, you have to use metallic. -If you want the 'dark' look, you should use dye or ceramic. If cost is the over-riding concern, dye-based is the usual choice... just be CAREFUL with the cleaning products, and watch for fading in the non-shadowed areas. (sunlight fading deosn't happen in the areas shadowed by the window seals etc, so if you start to see the main part of the window being darker than the few millimetres at the top of the window for example, your tint is almost certainly sun-fading).
I went with Ceramic. I got all seven windows done, plus the two open-skye roof panels. -Over here there's a lot of competition, since MOST people tint their windows to keep the summer temperatures less oppressive, and so that keeps the prices pretty competitive... Mine cost US$340 including the roof, and the pieces were laser-cut, and installed in an INDOOR garage (less dusty etc.)
My wife's last Volvo got a tint job from some "we come to you" guys who did the job in our driveway, and they cut the film to shape by laying it on the OUTSIDE of the window and cutting it with a razor blade. -This worked fine for cutting the film, but unfortunately the razor blades nicked the edges ALL OVER the outside rubber window seals... -
Bä$tìd$!!! -What's even worse, a few bits of grit on the outside of the car windows ended up "static-clinging" to the film, and then ended up between the film and the glass, where they stayed...
If you're getting it done professionally, ask HOW they cut the film to shape, if they do it indoors or outdoors under a canvas or whatever. the difference between a professional job and an amateur job is enormous!
Keith