Glass/Ceramic windows on fireplace insert

[woodfire]

I have a Jotul insert circa 1987. Just wondering, how do I determine what type of glass is used for the windows?

I do find that when I open the door I feel allot more radiant heat, so the glass seems to be blocking quite a bit of it. I am also aware that special ceramic glasses are better than tempered glass at transmitting the infrared heat rays.

How do I determine what type of glass/ceramic is in my system? The unit is way beyond the customer support window of what Jotul USA has defined, which is, according to them, 10 years (some tie in with one of those ISOXXXX registrations I was told) so I doubt that they would help.

If I did change the glass and it was a better transmitter, could it impact the system negatively in some way?

Can the proper glass really make a difference overall?


Any thoughts welcome.

 

[Corey]

Most likely any wood stove / insert has some type of transparent ceramic glass - or the really old ones (antique) might use mica. Tempered glass is great for fireplace screens, etc - but I don't think it would stand up the the heat of a wood stove. One sure way to tell would be to break it...if it shatters like regular glass, it is probably transparent ceramic...if it breaks into thousands of tiny cubes, then it was tempered glass.

You could search around and probably find some glass that has a bit higher transmittance. Some of the neoceram glasses are fairly transparent into the IR range:

http://www.ceramicglass.co.uk/downloads/neoceram_charts_1.pdf

You can see neoceram 0 has fairly good transmittance down into the mid IR range while neoceram 11 is fairly poor. But consider what is happening to that IR energy...it is either being transmitted through the 'glass', absorbed by it, or reflected back into the firebox. If it's transmitted, of course you feel the heat radiating from the glass, if it's absorbed and re-radiated, you feel that as well. If it's reflected back, it increases the overall temp of the firebox and you get higher temps from the rest of the stove. Overall, I think you'd just be shifting heat around...maybe a little more out the front and a little less out the top/sides. But I don't think you'd be substantially increasing the overall amount of heat output.

 

[Hogwildz]

Measure the exact size of the present glass in there, then go to:
http://www.onedayglass.com
order the Neoceram, and your all set when it arrives.
Just double check the actual thickness. Neoceram is 3/16" or 5mm thick