Low iron triple glazing

Rock12

Hi all, I am about to purchase the windows and doors formy new build. The glazing will be argon filled low e coated but my question is; would the more expensive low iron glazing give me a clearer glass. The ordinary glass has a greenish tint it seems and I would appreciate anyone's opinion or experience on if the low iron glass provides a clearer unit or is worth the extra expense? Thanks.

martinn123

i'm not familiar with the particular product, but attached a Table you might find useful.

It compares,

LT (light transmission) Amount of light transmitted through the glass.

LR out (external light reflection) the percentage of visible light reflected away from the outer surface of the glass, compared to the total visible light that reaches the glass at 90 degrees.

LR in% (internal Light Reflection) the percentage of visible light reflected away from the inner surface of the glass, compared to the total visible light that reaches the glass at 90 degrees.

SF = Solar Factor, commonly used in Europe sometimes known as ‘g’ value is the same as Solar Heat Gain Coefficient (SHGC) used in the USA. The Solar Factor is the ratio of the total solar energy entering through the glass compared to the incident solar energy. This total energy is the sum of the solar energy entering by direct transmittance and the part of the energy absorbed by the glass and re radiated to the inside.

SC = Shading co-efficient Comparison of the performance of the glass specified to 3mm clear float which has the highest solar factor.

U value = the relevant insulation value of the glass as per EN673 calculated as Heat transfer through the glass, most of our range offer 1.1

Other values

Relative heat gain, energy reflection, absorption and transmission and solar energy need attention when considering the application of heating and ventilation systems and adherence to local regulations on emissions and energy consumption

We use various edge sealants depending on the specification HD Silicone, polysulphide and polyurethane are all offered and we fill the airspace with argon gas as standard. Krypton gas is an option as an alternative if further insulation performance is called for, and triple glazed units are a standard production item for us.

From one Major Glass supplier.

A fella called fish

It's like looking at diamonds. Very difficult to tell unless you're an expert or looking at it through a microscope....but it's your money..

fclauson

Glazing can make a big different to the thermal performance of your build - check out some of my older posts - the "g" factor which covers solar energy transmittance can vary a builds performance considerably

http://www.boards.ie/vbulletin/showthread.php?p=76778310

Rock12

Thanks for the informs links, just what I was looking for. I had initially speced my south facing glazing with low iron for solar gains but I wondered if rest of the glazing may benefit from the low iron with additional gains and possible less tinting of the units.

Not to drag the thread off topic but in my build i am installing a large curtain walling of 32 square mtrs with 4mtrs in height. on the mono roof over this i have a three foot overhang, would this in your opinions cause too much shading in summer considering the weather we get?

BryanF

Rock12 wrote: »

Thanks for the informs links, just what I was looking for. I had initially speced my south facing glazing with low iron for solar gains but I wondered if rest of the glazing may benefit from the low iron with additional gains and possible less tinting of the units.

Not to drag the thread off topic but in my build i am installing a large curtain walling of 32 square mtrs with 4mtrs in height. on the mono roof over this i have a three foot overhang, would this in your opinions cause too much shading in summer considering the weather we get?

Perhaps you could post/ paste a paragraph on 'low iron' from the manufacturers data?

Rock12

Hi Brian, the following are the details given by the window manufacturer. It states the solar gain benefits of the low iron glazing. I have talked to the company and was told the low iron glass has a fraction less tinting but its not overly noticeable. I think I will opt for the low iron glass as its not a great deal dearer and the extra money should be re couped quickly by any heat gain lessening the need for alternative heating completely.

"Our triple glazed window units are constructed with three panes of glass (outer pane either planilux clear Float or Diamant Low-Iron, the inner and inside pane of Low emissivity). The panes of glass are spaced out with a Warm Edge Black swisspacer, than the two airtight chambers are filled with Argon gas and sealed up creating a double insulating barrier for your home.
Triple Glazed Units (click on images to view)
Planilux Clear Float + Low-E
Diamant Low Iron + Low-E


Benefits of Triple Glazing Windows
Solar Gain
Once again we offer two options planilux clear float glass or Diamant Low-Iron glass for the outer glass of triple glazing unit to increase your Solar Gain in your home."

sbsquarepants

I work for a commercial glazing company, and where as we haven't used triple glazing anywhere, we we have often used low iron glass, both single and double glazed. It is noticeable clearer when you see it side by side with standard iron glass - but without comparing it to something i'm not at all convinced you'd notice. If there is much of a price difference - i wouldn't bother.
Incidentaly i personally wouldn't bother with triple glazing at all, unless you live beside a busy road or the airport or something like that.

BryanF

Rock12 wrote: »

Hi Brian, the following are the details given by the window manufacturer. It states the solar gain benefits of the low iron glazing. I have talked to the company and was told the low iron glass has a fraction less tinting but its not overly noticeable. I think I will opt for the low iron glass as its not a great deal dearer and the extra money should be re couped quickly by any heat gain lessening the need for alternative heating completely.

"Our triple glazed window units are constructed with three panes of glass (outer pane either planilux clear Float or Diamant Low-Iron, the inner and inside pane of Low emissivity). The panes of glass are spaced out with a Warm Edge Black swisspacer, than the two airtight chambers are filled with Argon gas and sealed up creating a double insulating barrier for your home.
Triple Glazed Units (click on images to view)
Planilux Clear Float + Low-E
Diamant Low Iron + Low-E


Benefits of Triple Glazing Windows
Solar Gain
Once again we offer two options planilux clear float glass or Diamant Low-Iron glass for the outer glass of triple glazing unit to increase your Solar Gain in your home."

Have you gotten : overall uvalue glass & frame combined + glazing factors (these would generally include o/l, lt, sht)

sydthebeat

Rock12 wrote: »

Not to drag the thread off topic but in my build i am installing a large curtain walling of 32 square mtrs with 4mtrs in height. on the mono roof over this i have a three foot overhang, would this in your opinions cause too much shading in summer considering the weather we get?

4.0 m high and only 900mm of over hang....

definitely not too much shading, if anything too little, depending on the energy performance of the house.

900mm over 4000mm only gives a 77 degree
usually you want to create a 60 degree shade

Rock12

The overall U value of glass and frame is 0.7, as far as I am aware the insulating value of the glass is not deminished by the low iron option but it effects the solar admittance making it a more visalbe option when used in the suns trajectory. I know the glass suppliers to the window joinery and have read their spec on this glass and it is a step up in glazing.

As for the overhang, I want a certain amount of solar admittance for the curtain walling as I feel the light is more important than the heat as the heat recovery or opening a large sliding door on that curtain walling can deal with the excess heat. My problem or worry is how much is enough or too much. Going with those angles of shade given I will work out the shading and do some calcs for the shading offered through different months. Thanks for the input!

fclauson

I would suggst you do a PHPP calc

overheating is a big issue with that much glass (call me late august to see if I got my maths wrong on mine !!!!)

Even in the mid winter my house went up 2deg when the sun came out due to solar gain