Window tinting

Hi
I have a 1 bed unit in Melbourne with large north facing and south facing windows. I need to reduce the heat in summer. Am having ceiling insulation installed and curtains.
Re solar film
1. Can anyone tell me if having just the north facing windows lined with solar film will benefit me. Finances are a bit tight so don't want to have all the windows done if not absolutely necessary.
Or it is a must to have all done.
2. Is there any particular rating etc that I should be considering when i get quotes?
All suggestions most appreciated.
many thanks

I don't know if there is a standard rating for films:

http://www.wers.net/residential/wers-for-window-film

The windows parameter is SHGC - solar heat gain coefficient. The lower the better.

MEP films just talk about total heat energy rejected. The higher the better.

http://www.mepfilms.co.nz/brochures/mep_spec_guide.pdf

The solar film will help in summer - but your winter wamtrh will also be affected.

So I'd suggest that a small awning on the outside might be a better option - that way if properly designed it could let in the winter wamth and stop the summer heat.

Good summer gain reducing windows films will do the summer bit - but think about both seasons.

Its fine doing just a few selected windows. A medium dark window film can block 65% heat, 85% glare and 99% UV without making the room too dark, that can mean a 5-6 degree drop in room temperature. Factor about $60-70/m2. You can get low-e window tints as well that will block the same amount of heat but outperform heavy curtains and most double glazed windows for winter heat retention, you might need to call a few tint shops to find someone who can get it.