Interior Window Film vs. Exterior Window Film

Exterior Prestige 20 on Statehouse Restaurant in Commerce City, CO

In a recent Sales Meeting we had a discussion about creating some marketing material we could send out to customers weighing the options of our Interior Prestige Window Films vs. our Exterior Prestige Window Films. We wanted to have a simple answer or solution for our customers that would make it easy for them to decide which film product they wanted. However when weighing the pro’s and con’s it was easy to see that Exterior Film will almost always be the answer.

While I love our Interior Window Films, and a 20%-43% heat reduction is nothing to balk at, it’s difficult to convince someone that this is a better option than an exterior product that will provide a 59% heat reduction, because it isn’t. If heat, and wanting to reduce your solar heat gain are the main issue for you, than an exterior film will almost always be the way to go.

Now that I have you hooked on the idea of an exterior film, what would be some reasons to go interior. Well there are a few. Exterior Window Films are applied outside in the elements. In Colorado this means we have approximately 6-7 months to complete these installations. And the conditions need to be good. Think of a nice Colorado day with low wind and no rain or snow. That’s what we need. Check out our Exterior Window Film brochure for more detailed information on the requirements we need for a clean installation.

Other reasons could be French Paned windows, or Wood Framed Windows. These are not good candidates for exterior window films. The intricacies of these windows require a clean indoor climate to attain IWFA visual quality standards.

3M Exterior 40 application in Aspen, CO

There is also cost and warranty. Exterior Window Film is more expensive than interior, this is due to the cost of the materials, and the additional time needed to install these films safely and correctly. Exterior Window Film warranties are for 10 years, vs. an Interior Film Warranty which can be up to a Lifetime for residential customers.

Many times heat may not be a huge issue, but fading is. In that case, one of our interior films will work great for you. All window films reduce 99% of the UV Rays whether they’re dark and reflective, virtually clear, or on the outside, you’ll get fade protection regardless of the product you choose.

Well there you have it. This is wordy, I know, but I feel we have need to be forthright with our customers, and if you want heat reduction, exterior is probably the way you want to go.

If you have any questions about our Window Film Products and services, please don’t hesitate to call or email us at info@coloradosolarvision.com or 303-862-6376.

You can also visit our Solar Control Window Film page to access data, and warranty information.

Solar Heat Reductions are not absolute. These are estimates based off of a standard clear double paned window with an approximate solar heat gain coefficient of .70 prior to having window film applied.

Alex working hard applying Exterior Prestige to a home in the Denver Metro area.

3M Exterior 40 going on Regis Jesuit High School in Aurora, Co

Exterior Prestige 40 on home in Commerce City, CO

Looking at Window Film Data

Have you ever been asked to look at data you aren’t familiar with, and to decipher it yourself? If not, you probably will soon if you’re shopping for window film. We in the Window Film Industry have a tendency to hand over product cards with tons of data, but not much insight on what it all means.

When shopping for window film, you’ll be handed a window film card, generally with an enclosed sample, and all the pertinent info about that product on it. But what does it mean to you, and what data or numbers should you be most concerned with? Well that all depends on what you’re buying solar control film for. Is it fading, one-way visibility, or just plain heat. This data can help you figure out which film product will work best for your needs.

The technical data above is for 3M’s Interior Prestige Window Film Products, and since most of us are looking to add film to double paned clear glass, we’re going to use those numbers in our examples below.

The First Number you’ll notice on Prestige or any window film card for that matter is a number following the name of the product. This number roughly represents the amount of visible light transmitted, and this is generally true for most window film manufacturer’s products.

Product Name = Visible Light Transmitted (The higher the VLT, the lighter the film). If you want to add a film that will not change the look of your glass, you’ll want to choose a window film with a high VLT, and probably not anything with a VLT under 45%.

• Prestige 70: 62% VLT

• Prestige 50: 45% VLT

Now that we know why a film is called Prestige 70 or Night Vision 15, we can easily decipher which film products will change the appearance of our glass. If you don’t want to darken your glass, this will limit you to films with a VLT of 45% or higher. If you don’t mind darkening your windows, you’ll have an even wider variety of options.

Once you’ve settled on how dark or light you want your window film, you’ll be able to utilize the technical data to find the perfect window film for you. Below are explanations of what all the acronyms and data mean.

Visible Light Reflected Interior: This is the amount of reflection the application of window film will add to the interior side of your glass.

Many window films will have a high interior reflection, some can even cause a mirror effect, especially at night. If you want to see out of your windows at night, you should probably stay away from window films like 3M Silver P18 series with high interior reflectivity, and opt for products with low interior reflectivity like 3M Night Vision series.

Visible Light Reflected Exterior is the amount of reflection the application of window film will add on the exterior side of your glass.

The higher this number the more reflective your glass will be. This is an important number to look at if you are wanting to add film for daytime privacy. Prestige 70 would not provide this for you, you’d need to look at a film with a VLR Exterior of at least 20%, like one of 3M’s Night Vision products.

• Prestige 70 VLR Interior: 13%

• Prestige 70 VLR Exterior: 15%

• Night Vision 15 VLR Interior: 11%

• Night Vision 15 VLR Exterior: 39%

SHGC (Solar Heat Gain Coefficient): The lower the number means the better the heat reduction performance.

• Prestige 70 on Double Paned Glass: 0.56

• Prestige 50 on Double Paned Glass: 0.53 (Prestige 50 blocks more heat than Prestige 70)

Solar Heat Reduction: This is the estimated reduction in heat transfer with the application of window film. The higher the number, the less heat transferred through your glass.

• Prestige 70: 21% heat reduction when added to basic clear double paned glass.

• Prestige 50: 25% heat reduction when added to basic clear double paned glass.

UV, Ultra Violet Light Rejected: All Window Films will reject 99.9% of the UV Light. This is because the UV inhibitors are the in the adhesive. UV is the main cause of fading.

Glare Reduction: The percentage of glare reduced with the application of a particular window film product. The higher this number, the better the film works at reducing glare. If you are looking to reduce glare in your home or office, you’ll probably need to look at a window film with a glare reduction value of at least 50%, like one of 3M’s Night Vision products to have any real benefit.

• Prestige 70: 22% Glare Reduction

• Prestige 50: 44%

• Night Vision 35: 60%

• Night Vision 15: 82%

While this doesn’t touch on every piece of data, and we’re only looking at a few different film types, you may still have questions. If so, give us a call @ 303-862-6376 or email us at info@coloradosolarvision.com. We’re here to answer your questions Monday-Friday 8am-5pm.

All info provided in this BLOG is for educational purposes only, and does guarantee specific performance of glass after window film application. Numbers and estimated performance are based off provided 3M Technical data, tested using the application of 3M Solar Control Window Film on Double Paned Clear glass with an estimated SHGC of .70 prior to installation of noted window films.

Why Exterior Film?

One of the questions we get the most as a window film company is “does it go on the outside or inside”? Our answer is “both”! Generally window film is applied to the interior portion of your glass. This is great for durability, and access, and while interior window films perform great, sometimes they’re just not enough, and that’s where exterior film comes into play.

Exterior window film can be a great option for a couple of reasons. The number one is performance! Exterior film reduces the heat in its tracks. The heat is absorbed prior to even hitting your glass. Since the heat is absorbed on the first surface, this significantly reduces if not eliminates any potential glass breakage, while absorbing a drastic amount of heat. Another great use for exterior film is access. Skylights, and other hard to reach windows might not be accessible from the interior.

At Solar Vision Inc., our favorite product is 3M Exterior Prestige Window Film. 3M Exterior Window Films offer great performance, and come with up to a 15 year warranty. 3M Exterior Prestige Window Film is designed to last, and will keep your home or building cool, and comfortable for years to come.

Click here for 3M Exterior Prestige Technical Details!

3M Prestige Exterior 40 (PR40X) applied to first floor windows at this apartment complex to reduce heat in gym area.

3M PR40X can enhance the look of your home or building.