Coloured Roof Lantern

Double Glazed Units

Building regulations require glass to be a U value of 1.6 or less. Our standard is 1.4. The minimum value is 1.0, which is the Planitherm 4s with Argon.

Inner Glass Panel

To meet building regulations, the inner glass has to have a coating on the inside face of the double glazed unit (inside the glass unit).

We use Low E / Softcoat (St Gerbain) glass U value 1.4 – which has a slight blue tint. It has a better U value than K glass.

You cannot have totally clear glass.

Outer Glass Panel

Solar control and self cleaning outer glass also have slight tints and this in turn fractionally increases the tint of the finished double glazed unit.

Where solar control and self cleaning are both required we normally use Pilkington Activ Neutral glass which has a slight but neutral tint.

To achieve a lower U value (better unit insulation value) Argon gas filled units reduces the U value by 0.2.

The best U value for double glazed units would be 1.0 (Planitherm 4s glass with argon).

Other Notes

To cut ultra violet light out (UVA) laminated 6.4 mm glass will stop 99 % of UV. This is used to stop fabrics and antiques fading. It also helps mildly when combined with a toughened layer of glass to cut down noise transmission (dissimilar materials help break up the soundwaves). For extreme noise 'Acoustic Glass' is available.

Triple Glazed Units

We can provide triple glazed units at a U value 0.9. Please ask us for more details.