Argon Filled Double Glazing will save 26p / year?

[405 TD Estate]

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 =A36 so how much will it save on gas bills....

Well Thermal conductivity (w/m K) Argon =3D 0.016 Air =3D 0.0257

So argon =3D 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 =3D 12m^2

Then I guess window area =3D 8m^2

The difference in thermal conductivities (extra heat conducted by air) =3D 0.0257 - 0.016 =3D 0.0097 (call it 0.01 w/m K)

So 0.01 x 10 degrees (temp diference) x 8m^2 (glass area of house) =3D

0=2E8 watts

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

so 3285 hours x 0.8 watts =3D 2628 watt hours/year =3D 2.6kw

And at 10p/kwh for electricity cost =3D 10p x 2.6 =3D 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.

[visionset]

< 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

[dennis]

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.

[Peter Lynch]

... snip

Yes, TPTB agree with you

looks like the coatings on the glass makes much more difference

Pete

[405 TD Estate]

1= [e-mail]...

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 =3D 1/62.5 the thickness.

Or transmissibility =3D 62 x 0.01 =3D 0.62 (not 0.01)

This is not reflected in the NRWAS which says double glazed w/m^2 K =3D

2=2E7 and argon =3D 2.6 (both 16mm) w/m^2 K =3D 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) =3D 10x my original estimate so roughtly the cost per year would be 10 x 26p =3D =A32.60 / year.

Where - as the difference between normal and Low-E glass is 0.6w/m^2 K =3D =A32.60 x 6 (as above calculation but for 0.6 not 0.1) =3D 15.60/year.