Ok.

I'm in the process of renovating my failed double glazing.

One thought occurred - my MIG welder can use Agron Shielding gas and
new windows are argon filled. A gas bottle is £6 so how much will it
save on gas bills....

Well Thermal conductivity (w/m K)
Argon = 0.016
Air = 0.0257

So argon = 62% of air (i.e. transmits less heat/cold not surprising
since it is used in double glazing!)

If at a first guess I say the average year round temperature dfference
between indide and out is 10 degrees C

If my average semi house in the UK has an external window and door
area = 12m^2

Then I guess window area = 8m^2

The difference in thermal conductivities (extra heat conducted by air)
= 0.0257 - 0.016 = 0.0097 (call it 0.01 w/m K)

So 0.01 x 10 degrees (temp diference) x 8m^2 (glass area of house) =
0.8 watts

Say my heating is on for 3 hours in the morning, 6 in the evening = 9
hours/day = 9 x 365 = 3285 hours/year

so 3285 hours x 0.8 watts = 2628 watt hours/year = 2.6kw

And at 10p/kwh for electricity cost = 10p x 2.6 = 26p / year.

I'm thinking filling the windows with argon is not worth it!

If I've made any errors etc let me know. Also this may be a best case
scenario since conductivity of the silicone that seals the window I
expect to transfer a lot of heat (compared to the air) and reduce the
argon's effectiveness.

"405 TD Estate" wrote in message
ps.com...


I'm in the process of renovating my failed double glazing.

One thought occurred - my MIG welder can use Agron Shielding gas and
new windows are argon filled. A gas bottle is £6 so how much will it
save on gas bills....

...

I'm thinking filling the windows with argon is not worth it!

If I've made any errors etc let me know. Also this may be a best case
scenario since conductivity of the silicone that seals the window I
expect to transfer a lot of heat (compared to the air) and reduce the
argon's effectiveness.


Isn't the silicone a constant? You need it anyway.
If you don't fill with inert, what do you fill it with?
You need to get the water vapour out. Can you confidently ensure the air is
dry? Or does silca gel keep the H2O locked up under all conditions.

--
Mike W

"405 TD Estate" wrote in message
ps.com...

If I've made any errors etc let me know.

Where does the thickness enter into your equation?
1 m of material transmits less heat than 20 mm of material for the same temp
difference.

On 1 Mar 2007 09:49:36 -0800, 405 TD Estate wrote:
Ok.

I'm in the process of renovating my failed double glazing.

.... snip

I'm thinking filling the windows with argon is not worth it!

Yes, TPTB agree with you
http://www.nrwas.org/html/fensa.html
It looks like the coatings on the glass makes much more difference

Pete

--
.................................................. .........................
.. never trust a man who, when left alone ...... Pete Lynch .
.. in a room with a tea cosy ...... Marlow, England .
.. doesn't try it on (Billy Connolly) .....................................

On 1 Mar, 19:00, "dennis@home" wrote:
"405 TD Estate" wrote in glegroups.com...

If I've made any errors etc let me know.

Where does the thickness enter into your equation?
1 m of material transmits less heat than 20 mm of material for the same temp
difference.

Yes yes - this is an error in my calc's. Since the units do not
reflect or allow for the thickness w/m^2 K perhaps the thickness is 1m
(standard SI unit)?

If this was correct them 1000/16 = 1/62.5 the thickness.

Or transmissibility = 62 x 0.01 = 0.62 (not 0.01)

This is not reflected in the NRWAS which says double glazed w/m^2 K =
2.7 and argon = 2.6 (both 16mm) w/m^2 K = 0.1 w/m^2 difference.

So I'm not sure how thickness comes into it...

Anyway 0.1 w/m^2 K (from NRWAS website) = 10x my original estimate so
roughtly the cost per year would be 10 x 26p = £2.60 / year.

Where - as the difference between normal and Low-E glass is 0.6w/m^2 K
= £2.60 x 6 (as above calculation but for 0.6 not 0.1) = 15.60/year.