Effects on the unit’s thermal performance.

Basically, if the unit is air filled the re-engineering has no effect on the thermal performance of the unit, tests carried out and independently verified by a leading University in the UK compared a brand-new unit with an identical pressure equalised unit and the thermal performance was the same.

If you replace the failed unit with a gas filled, warm edge, low thermal emissivity glass unit it will outperform the re-engineered unit, however the saving made on lower heat loss over the next 5 - 10 years will never pay for the cost of upgrading the unit and what's more the unit will most likely need replacing again and again and again.

Save Your Windows, Save Your Money, Save the Environment.