Windows... The Challenge. Big windows provide wonderful light. Problem is that at night they allow anyone passing by to look into the house. Even if you don't need them for privacy you are losing a lot of light to what becomes a 'dark void' once the sun sets. So you need screening... blinds, curtains, shades

Traditional shades. They require daily attention and always have a cluttered look.
Privacy Screens. A clean, modern solution. Anyone can install with the most basic household tools.

As a General Contractor... in san francisco we were always asked to install privacy screens for offices and conference rooms. After passing on the fee of $400+ per window (yes, sf was pricey even 10 years ago) I decided to jump in and start applying film. One installation covered my costs for all with windows I installed and I could receive a bonus. Here's how you can too!!

Step 1: Materials

Required Materials:

Vinyl Film - I show the static method here. (film for static method at $1.07/sqft) OR (easier... self-adhesive film at $1.13/sqft) ---not a huge difference in price... it used to be much more expensive for self-adhesive
Spray Water Bottle + Soap - 10% dish soap + water solution
Cutting Blade - I love my olfa blade--they really are the best and have far superior blades than standard utility knife) ---here's my first blog post on the value of the olfa knife for architecture students
Credit Card - This is the useful tool for smoothing out the film. No need to buy a custom tool.

Optional Materials (shown in photo):

Squeegee - I bought this little guy 10 years ago and only used it for installing film. It was important to my clients that the installation was dust free... honestly, not necessary if you use newspaper to clean the window first. Probably should actually bring it into the shower for cleaning the glass... (here's a mini squeegee at $13)
Cutting Surface - always handy for crafts
Ruler - just need a way to transfer approximate dimensions
Application Tool Kit - this $10 application kit is worth a look but not worth buying... shown here. Most of the items you should already have.
Application Solution - pros tend to use a specialty solution that is meant to aid adherence... I never found it necessary but if you're doing a few and don't mind the expense ($15+) you may find it worth it.

If you want to buy in bulk you won't find on amazon. You'll need to shop Uline ($152 for 25'x36" roll) or a 3m distributor for the contractor roll of window film.

Note: Some of these are affiliate links, I will get a small commission if you buy through them (amazon:), at no additional cost to you. Thank you if you do buy through the links! If not, hopefully you will find the product details useful.

Step 2: Preparing Materials

Rough Cut Film. First cut out a section of window film with an additional 1/2" (1cm) or greater on each side. I typically just round up by 1" on the length + width. If you use a scissors and don't have a straight cut you'll want to add more (say 2" plus).

Mix Soap Solution. You'll want to use 10% plus of a soap solution. I have only ever eyeballed the solution. I did a few tests before going out into the field (as a contractor). If the film didn't stay adhered I added a touch more soap will I had the solution right. (should be 10-15%)

Step 3: Surface Prep

Clean the surface well. Any dust, bugs or hairs can be caught between your film and window.

Newspaper or computer paper is the best option for cleaning glass.
Squeegee is great too but not necessary for home installs... commercial installers will want to have one

Step 4: Fit Film

The exact size of the film is cut in place.

Apply a few sprays of solution across the clean glass
Press at the center and adjust as needed to align edges
Press from the center to the edges (no need to work out all the air bubbles yet)
Run your blade along the edge to cut film to shape

Careful --- as you cut to avoid the seal most windows have in place. If you short of the edge 1/16-1/8" (1-2mm) you won't notice. Professional installers always leave a consistent gap.

Step 5: Remove Bubbles

After cutting to fit you'll need to remove the air bubbles and excess solution.

Start a the top/center and move to the edges.
Short, smooth advances allow you to work the bubbles forward.

Avoid using any tools that will damage your film... some credit cards have burrs that can snag on film. They sell 'special tools' for installing vinyl film... but it's not necessary

Step 6: Enjoy Your Privacy

Where to start?

Garage. I demonstrated the installation at my garage... it's a great feature to have windows but all I ever want is the light. It concerns me that would-be criminals may spot something from the street.
Living Room. As I we walk around the neighborhood we can always see people sitting down for dinner or watching TV. I can't have that... I do love the natural light and only frost where it's necessary. With these double hung windows I go straight to the window edge. Easy to use stop at any height that's right for your home.
Office. Modern offices are very open. This is a simple way to get more privacy if you have a a glass wall or a sidelight. The 3' or 4' rolls work well. Easy to install a band to get a visual separation for colleagues when seated or in a meeting.

Thanks. Hope you've enjoyed this instructable and feel more confident getting started with privacy film. It's awesome day and night to not have to adjust blinds. Thanks for reading! Jeff

Here are a couple other instructables I've tinkered with over the past month...

Citric Acid Gets a Shaker - why citric acid is a fixture in our spice kit
Swiss Army Shelves - exposed kitchen shelves that are constantly working
Simplest Coffee Table - found door placed on two salvaged wine boxes

please consider a vote in the Stick It Contest :)