Supplied by ALTHERM, FIRST and VANTAGE window manufacturers nationwide the ThermalHEART roof window is supplied double glazed and allows optimum interior heat retention and minimising of troublesome overhead condensation.

The addition of a new, structurally glazed mullion, insulated from exterior cold (see illustration), means that overhead fixed lights in reasonable sizes can be specified by designers with confidence. The perimeter frame is thermally broken and the mullion sits below the glass line with effective thermal separation from outside cold, and banks of thermally efficient overhead windows can thus be designed.

The structural glaze design means that the window in both opening and fixed formats has no beads and no potential to trap or pond rainwater. It can therefore be installed at low pitches if required, while dual colour is possible to match interior and exterior colour schemes.