Tempered Glass

Fireplace glass doors come equipped with a specially tempered glass that is designed to withstand high temperatures. Tempered glass is actually normal glass that has been heat treated to make it stronger. It can hold up to the thermal shock of high temperatures, and has the ability to reduce injury because of its breakage pattern.

Tempered glass used in fireplace doors is rated to withstand temperatures of up to 500 degrees for sustained periods of time, making it a perfect fit for your fireplace. While tempered glass does a nice job of withstanding high temperatures, it can break if exposed to direct contact with flame. As a general rule of thumb, it is a good idea to keep flames at least four inches from your fireplace glass doors.

Tempered glass also breaks different than regular glass. Instead of splintering into long jagged pieces like normal glass, an entire piece of tempered glass will fragment into small pieces. Fireplace glass doors are typically built with ¼” thick tempered glass, and are available in clear, bronze tint, gray tint, or mirrored options. Tempered glass can also be etched and or beveled for an extra design flair.

When purchasing fireplace glass doors, one of the most important features to consider is the material out of which they are made. If you are looking for a higher quality metal and you enjoy the ‘polished’ look, Solid Brass is a great choice.

Brass metal is a very good material for fireplace doors because it is an alloy. An alloy is a compound that is comprised of two or more metals to increase the hardness of the resulting product. Brass that is yellow in color is made up of mostly copper and zinc. Copper or zinc alone would not be a suitable metal for fireplace door frame, but when combined they create a metal that is very strong and glossy.

Many customers choose brass for their fireplace glass doors because it looks similar to gold and it is relatively resistant to tarnishing – which means low maintenance. Most fireplace glass doors that are made from brass also feature a clear protective lacquer finish that coats the metal which nearly eliminates the possibility of the frame tarnishing.

Low maintenance, the look of gold and exceptional durability combines to make solid brass a great choice for fireplace glass doors for homeowners that enjoy a traditional and elegant decor.

When purchasing fireplace glass doors, one of the most important features to consider is the material out of which they are made.

Wrought Iron that is used commercially is nearly 100% pure except for a small amount of carbon. The iron is tough and durable, yet it is pliable and can be easily shaped making it ideal for commercial use.

The term wrought iron simply means that the iron has been formed or “worked” on – which in old English, the past tense for “work” is “wrought”.

Manufacturers have been using wrought iron to make fireplace glass door frames for some time. The metal is stronger and less prone to dents and scratches than anodized aluminum, and should be considered an upgrade. A major benefit to wrought iron is its ability to have a powder coat finish. The powder coat finish is much better than a wet finish where the paint is sprayed onto the frame. With a powder coat finish, an electrostatic charge is used to solidify the painting process. The result is an attractive, durable, high quality finish.

Fireplace doors that are made of wrought iron will tend to be priced a bit higher than an anodized aluminum door but less than an all steel door. The metal used for an all steel door has a higher carbon content which makes it even stronger than wrought iron, but the look is the same.

If you’re working on a tight budget, and you don’t necessarily need the quality of an all steel door, a wrought iron fireplace glass door can give you the same look as steel at a lower price.

Fireplace Glass Doors Materials - Aluminum

When purchasing fireplace glass doors, one of the most important features to consider is the material that they are made of. There are a number of different types of materials used to fabricate fireplace glass doors, each having their own advantages.

Anodized Aluminum

This material is widely used for fireplace doors because of its beauty and durability. Aluminum is known for being lightweight and resilient; however, the addition of the anodized finish makes the aluminum extremely hard. The anodizing process is an electrochemical process that thickens and toughens the naturally occurring protective oxide. The result, depending on the process, is the second hardest substance known to man, second only to the diamond.

What does this mean to you?

The anodized aluminum frame is difficult to dent or warp and it is resistant to both abrasion and corrosion. The anodized aluminum will not tarnish, so it is very low maintenance. Also, because the anodizing process allows for dyes, the aluminum can be manufactured in a number of different colored finishes, making it easy to fabricate the fireplace door frames.

Though anodized aluminum is not as high quality as solid brass, wrought iron, or steel, there is a large supply available. This keeps the price low, and makes this material a great choice for low- to middle-end fireplace glass doors.

Fireplace Glass Door Materials - Steel

When purchasing fireplace glass doors, one of the most important features to consider is the material that they are made of.

Steel is used in the fabrication of fireplace doors because of a few unique benefits that steel provides. Steel can be finished using a number of different methods, including the powder coat finish. Steel is also very durable and able to withstand the temperature fluctuations of the firebox. Other door frames made of lesser material may expand and contract with the change in temperature. In some instances, when the frame becomes too hot, the metal will expand and the doors will not open. In a worst-case scenario, the frame could be permanently altered or cracked.

Because of the durability of the material and the ability to apply a finish using multiple methods, steel is considered the optimum material for a fireplace glass door and is well worth the added cost.

Tempered Glass VS Ceramic Glass in Fireplace Doors

Most fireplace glass doors are manufactured using ¼” tempered glass. Tempered glass is simply glass that has been heated in a furnace and then quickly cooled. This process increases the strength of the glass and the ability of the glass to withstand the high temperatures associated with a fireplace. The average thermal shock rating (the temperature at which the structural integrity of the glass will fail and shatter) is between 400 -600 degrees Fahrenheit. This is usually sufficient for most wood and gas fireplaces.

Tempered glass is indeed the preferred glass for manufacturers for most fireplace doors because they have found that the increased strength of the tempered glass can make up for the weak structural integrity of many aluminum frames. Nearly all fireplace door manufacturers offer a lifetime warranty on the tempered glass, but as with all warranties, you must read the fine print. Most fireplace door warranties will tell you not to burn the fire with the doors closed or the warranty is voided; the reason being that a large fire could potentially exceed the thermal shock limits of the tempered glass and crack or shatter the glass.

To be fair, no manufacturer knows the exact condition of a customers fireplace or the size fire a customer intends to burn (turns out many homeowners enjoy bonfires in their fireplaces). So the question is often asked, “If I shouldn’t burn a fire with the fireplace doors closed, what is the purpose of the draft assembly?” Well, the answer is – so you can burn with the doors closed and still have combustion air feed the fire. This is a contradiction, but again, fireplace door manufacturers can’t be responsible for what someone does in their fireplace.

While I would never recommend forsomeone to burn a fire with their doors closed and the draft assembly open (for obvious legal reasons), if you were going to do so I would definitely recommend that you keep the fire about 6” back from the glass.

There is another alternative that is becoming increasingly popular; ceramic glass. Ceramic glass is a great option for fireplace doors for two main reasons:

1. It has a thermal shock rating of around 1380 Degrees Fahrenheit – far exceeding any fire you would want in your fireplace.

2. The process for creating ceramic glass is simplified allowing fireplace door manufacturers to stock and cut it themselves – what does this mean to you? A fireplace door manufacturer doesn’t have to wait for the glass to come in from the glass company which drastically reduces the build time for your fireplace door.

Are there any downsides to ceramic glass? I would say just one. While the thermal shock rating for ceramic glass vastly surpasses that of tempered glass, it does not have the same structural integrity. This could be an issue for aluminum fireplace doors that are not as sturdy as steel doors and are benefiting from the added integrity that the tempered glass provides. For this reason, I would stick with tempered glass in aluminum doors and ceramic glass in steel doors.

Bottom line: ceramic glass is a great upgrade for two reasons:

• Allows you to burn a hot fire with the fireplace doors closed
• Dramatically reduces the build time from 4-5 weeks to maybe just 1 week depending on the manufacturer.

There is a fireplace door on the Woodland Direct web site that features ceramic glass as a standard option. It is called the Sentry Fireplace Door and it has an incredible build time of just five days. Comes with a draft assembly so you can burn with the doors closed and it feature a flat black finish on a 3/16” steel frame.

Fireplace Door - Hidden Air Draft Assembly - Part 2

In my last post I discussed the primary purpose of a hidden draft assembly. In this post I want to discuss a secondary, yet somewhat controversial purpose of the draft assembly.

Here is the issue - you can technically burn a fire with the fireplace doors closed and the draft assembly opened. The draft assembly will allow enough combustion air to feed the fire rather than having your glass doors wide open. How does this benefit you? Having the glass doors wide open means that a substantial amount of air from your room is feeding the fire. This is air that you have paid to heat – since you typically are using the fireplace in the winter time. Keeping the fireplace glass doors closed will limit the amount of air that the fire is using, which in theory will save you money because you are not using as much conditioned air. I have talked to a number of homeowners that tell me that when they have a fire burning in the fireplace with their fireplace doors wide open their furnace will be constantly running. This is because so much of the conditioned air is being sucked out of the room and up the chimney. When you combine the savings you receive by keeping the fireplace doors closed with the radiant heat from the fireplace, your net heat is substantially increased when you burn a fire with the fireplace doors closed.

So if the above method is a cost savings and even preferable; why is it controversial? The reason is that all fireplace door manufacturers warn that if you burn a fire in the fireplace with your doors closed, the lifetime warranty on the glass is voided. In other words, if the glass breaks while your burning with the doors closed, you will be responsible to replace the glass.

Your fireplace doors use tempered glass which is rated up to approximately 600 degrees Fahrenheit. This should be sufficient for any normal size fire however there are other factors that can contribute to glass breakage. Since each fireplace is unique and these factors unforeseeable, fireplace door manufactures require that you burn the fire with the doors open.

I would never tell you to do something that would void your warranty – BUT… if you were still going to do this despite your warranty being voided; here are a couple of things to keep in mind:

1. Always keep the doors open when using gas logs. Do not ever burn gas logs with the fireplace doors closed. A gas fire is hotter than a wood burning fire.
2. Don’t burn a bonfire in a fireplace! Keep the size of the fire reasonable.
3. Keep the fire at least 6-8 back from the glass.
4. Don’t go from 0 to 60 in 6 seconds! What I mean by this is; don’t get the fire too hot too quick. One of the reasons for the glass breaking is the quick change in temperature. All things in moderation.
5. If you are really set on burning a hot fire with the fireplace doors closed, consider purchasing a fireplace door that features ceramic glass - such as the Sentry Fireplace Door. It's not inexpensive but it may be worth it depending on your desired application.
6. If you were to have glass breakage - don't freak out. You can purchase replacement tempered glass on our website and it is really easy to install. It's also not that expensive.

So there you have it – everything you could have ever wanted to know about the hidden draft assembly for a fireplace door – and then some!