12 things to know about Low-E Window Glass and Film

Are you looking for a cheap way to insulate your home? Bonus points if it’s low-hassle. We bring you the perfect guide to taking care of your home in both winters and summers with Low-E solutions.

Find out all the 12 things to know about Low-E Window Glass and Film in this guide below.

3 Low-E windows

1. What is Low-E glass, and how does it work?

Low- E stands for low emissivity. It is one of a kind since it withstands your windows against ultraviolet and infrared rays. It has a surprisingly thin coating that keeps your home insulated against heat in summers and against the cold in winters.

A couple of factors are used to measure such products’ effectiveness.

  • The U-value: This is the value assigned to glass to see how efficiently it retains heat.
  • Visible Light Transmittance(VLT): Through this, you can measure the amount of light filtered through to the other side of the glass.
  • Solar Heat Gain Coefficient (SHGC): How much solar radiation does the glass allow? Is it directly absorbed or radiated? It is known through this coefficient.
Large Low-E glass window

2. Low-e Window film gives great results without replacement.

Can’t afford to replace windows altogether? We’ve got the perfect solution! Allow window film to work for you. These thin sheets of plastic can be stuck inside the windows and do a great job of protection.

These sheets come in rolls like toilet rolls or kitchen rolls. Since it’s such an easy job, one can do it alone without needing any professional.

The substance that does the work is a metal oxide or metal. This coating will allow your home to be insulated for longer. You’ll end up saving bills for cooling and heating both!

Some films like this one will also have a one-way mirror effect. You’ll also get the options of several colors like:

Low-E window in a garage

3. Low-E tint is a perfect option for those looking to avoid replacement.

Tinted glass is also something people opt for when wanting to heat or cool the home or office better. A tint is often used more in large office buildings as well. The blackened windows you might see in high-rise buildings are nothing but tinted glasses.

Tinted glasses do have the effect of absorbing the direct sunlight on the windows. This means offices can save on their air conditioning bills.

Since the tint absorbs the sun, you won’t see much brightness inside. Unlike clear windows that can illuminate a room fully, you’ll mostly be left to your electrical lighting devices.

This tint can also be seen on some car windows. A good tint like this one will also give you a lot of privacy since it will no longer leave your windows see-through. You could almost be driving around in your bra, and no one would notice.

4. Low-E Vinyl Windows to leave no stone unturned in insulating

Commercial use of Vinyl windows with low emissivity is increasing every day. As global warming is increasing and ozone is depleting, we are facing more harsh sunlight than ever.

The temperatures have risen to record-breaking heights, and the effect of the ultra-violent rays is unimaginable. One way to tackle the unwanted heat and damage is to install good windows.

Maybe you’re looking to install new windows that are good at keeping away harsh outside temperatures and keeping insides cool. Low-E vinyl windows are a great alternative.

They don’t cost much more than regular windows and can guarantee you a UV-free existence even as global temperatures soar.

Low-E windows

5. Benefits of Low-e glass that are Low-key Life-saving

Many thoughts are put in before constructing an office or putting together a home. And one of the crucial decisions is about the insulation. Low-E helps with this. Let’s take a look at how:

  1. Protect from UV rays

With the ozone layer depleting and global warming on the rise, ultraviolet and infrared rays can lead to a great amount of damage to the human race.

While it is essential to practice eco-friendly behavior, it is also essential to protect yourself. That’s why Low- emissivity windows or film are great. They keep out the harmful rays that can potentially even cause cancer and several other diseases with too much exposure.

  1. Insulating

The biggest factor for installing this product is its tremendous insulating capacity. It can keep your home super cool in the summers. When the heating is up in the winter, it’ll retain it in the house and prevent the cold from getting in.

Metal oxide in the glass forms a firm layer of protection that allows for superb insulation.

  1. Energy saving

Since it won’t let air-conditioned or heated air out, you’ll end up not using the thermostat as much. You’ll save a lot on your energy bills since your heat never escapes!

You can end up saving between 10-40% on your heat loss in the winters!

  1. Natural light

A blackened screen isn’t what you always need to opt for if you want insulation. Low-E offers the benefit of letting natural light flow and illuminate the insides of your home.

  1. Durable soft-coat

The soft coat type of Low-E is sealed within the unit. This means it won’t be able to get scratched for years. Your cat can scratch away, or the kids can experiment with crayons. However, this won’t affect the coating.

one Low-E glass window

6. Problems with Low-E glass windows that you must know

While there are many benefits of Low-E glass windows, there are also some problems. Let’s take a look at them.

  1. More expensive 

Regular windows cost anywhere between $40-$75 for a single window. Double panes can cost you up to $800 for one since they are even more protected, while bay ones will be anywhere between $500-$1000. The type you want will decide the exact cost. If it’s expensive, like French windows or Casement, they can even cost $1500.

Low-E is installed on a square foot basis. While regular glass will cost $20 per foot, low emissivity will cost up to $30-$35 per square foot. Hence, you will have to loosen your purse strings for this one.

  1. Less sunlight

Although they don’t block out light completely, you won’t get the full feel of a sunlit home. A lot of the glare and sunlight will be blocked out. You won’t be able to tell the weather outside clearly. Sometimes, this can be a blow as the house may look gloomy because of the less light.

  1. Melted furniture

Yes, it’s surprising to hear. However, this is an issue. You have to be careful about what you place outside the windows. Since they deflect harmful rays and sunlight off the surface, they can burn patio furniture, pool liners, and any plants you may have lying around.

The concave surface acts as a magnifying glass. Hence repeats of your childhood experiments take place on a hot summer day.

two Low-E windows

7. Types of Low-E glass you can choose from

It’s not just the decision about whether or not to install this glass, but also which type that homeowners must make. Let’s take a look at which is the right fit for you.

  1. Solar control

It is a type of coating that is applied to the Low-E glass. It is typically used on the west and south-facing windows in a home. The purpose of solar control windows is to keep the heat out and limit the heat going inside. Buildings are kept cooler in this manner. Thus, this type is more prevalent in hotter areas. It makes inside cooling more effective.

  1. Passive

You can think of this one as the opposite of solar control. The passive coating is for saving heat energy inside the home. They will maximize the heat passing through the glass so you can save on your energy bill used to heat the home.

That’s why you’ll often find this type of window in the colder regions of the planet.

8. How are they made?

While the types are passive and solar control, they can be made using two different methods. You will spot it once you get into the buying market.

  1. Hard coat

Hard coat is the name given to the pyrolytic process. Herein the metal is melted and applied to the sheet of glass. When it cools and hardens, the result is a strongly welded Low-E coated surface that is more durable.

  1. Soft coat

It uses the method of vacuum deposition. In a vacuum-sealed chamber, the metal particles are deposited onto the glass. The result is a thinner coating that is not as strong but still effective as a hard coat.

9. Low-e windows cost, and is it worth it?

The cost of a regular window is less than a low emissivity glass. Look at the price difference and decide for yourself if it’s worth the cost.

While regular glass will cost you $20 per square foot, Low-E will cost you anywhere between $30-$35. If you’re ready to pay the extra few bucks, you will save hundreds on your energy bill. Whether it’s the summer or winter, you’ll be in for much less the cost of the air conditioning or heating bill.

Needless to say, it is worth the cost that you will be paying!

10. Is Low-E glass worth it, or should you make do with regular?

The prices are certainly higher to beat Ultraviolent and infrared rays, but it is worth it. You will reduce the glare from your windows and filter the sunlight. The major reason to buy this product is to increase insulation in the home.

This insulation will save you hundreds of bucks in the coming years. It is because you’ll be able to retain heat in the winters and cold in the summers with these windows. The insulation properties make this worth a buy.

Apart from this, you’ll also be letting in natural light into the home and thus reducing the need for artificial lighting in the daytime. It means you’ll even end up saving on the electrical bill!

All this and more makes Low-E worth it!

11. Low-E tempered glass and its benefits

Tempered glass is manufactured by heating it slowly until it reaches high temperatures. After this, it is quickly cooled. The fast cooling makes the surface cooler while the interior remains hot. The friction between the two causes the particles to break down into very small pieces.

The benefit of this product is its durability. It’s stronger than regular glass. Thus, it’s usually placed in areas like bathrooms, patios, and poolside windows to resist easy breakage.

Even if broken, the glass will not break into damaging long shards. Instead, it will break into circles that won’t be as harmful while trying to clear them up.

When you combine this superpower with the power of less emissivity, what you get is a high-quality window. It is resistant to wear and tear and capable of insulation. That’s why tempered Low-E windows are one step above the rest. Of course, you can also use film. However, it won’t be as long-lasting as the glass itself.

12. U-value of Low-E glass that will surprise you!

U- value refers to the amount of heat that the glass lets through the window. The rule of thumb is the lower the number, the better the quality.

While clear glass has a u-value of 0.480, Low-E, with only one single coating, has a value of 0.280. With two coatings, the number gets reduced even further down to 0.133. The numbers given here are in the W/Sq m- C unit or BTU/hr-sq ft-F.


Let’s look at some of the most asked questions about this topic.

Which is better, Low-E or double pane windows?

Double pane includes two sheets of glass with a pocket of dry air between them. This helps insulate your home. Double panes are also measured for U-value and solar heat gain. When compared in terms of U-value, Low-E glass has a lower value of 0.280 than the double pane of 0.480. Thus Low-E is the better choice. The solar heat gain coefficient is also less with Low-E and thus making it a better choice for insulation.

Can you see through Low-E glass?

Of course! You can see everything clearly through the glass, even with all the benefits of insulation and reduced radiation.

The metal oxide coating is not blatantly visible on the glass and looks like a regular windowpane.

With tinted windows, you would be reducing visibility and light to increase insulation.

Do Low-E window films work?

Yes, of course! And they are a neat replacement when you can’t afford the full glass. Window films can be put up during winter or summer to reduce energy bills and keep your home at the optimum temperature for longer.

These films are available in thin sheets that are available in rolls online or at your nearest Home Depot.

Does Low-E glass keep cold out?

Yes, certainly. However, it would be correct to say that it keeps the heat in. If the type of glass is Passive, you’ll also be maximizing the heat on the outside. The passive glass will let the maximum heat inside whenever the sun shines so your home stays warm.

It is ideal if you’re looking to keep the cold out and the heat in!

Do not opt for Solar control glass in colder regions because it will minimize the amount of heat entering your home.

Can you put a film on Low-E glass?

Yes, you can perform this function by yourself in most cases. In some cases, it won’t be viable. Putting the film on Low-E glass is not recommended if the coating is on the inside of the house. It will counteract the insulation and hinder its existing benefits.

If the window is double paned, you can attach the film without worry. It will enhance the insulation. In the double-paned glass, the coating is usually on the inside. It’s between the two sheets of glass which won’t disrupt the process.

How much does a Low-E window cost?

Consider that Low-e glass can cost about $30 per square foot, and a standard window is about 12 square feet. You’re looking at an expenditure of about $360 per window. Some glasses can be cheaper. Still, you’ll be looking at a minimum price of $200 per window.