Rationel windows achieve Passivhaus standard at lower cost

WARM – Passivhaus energy consultants say Rationel’s slim framed Danish timber window products can achieve Passivhaus Standards with slimmer frames, without thermal insulation in the frames, and at a lower cost.

Director, Sally Godber says that Rationel’s timber window product is very reliable and an essential marker for Passivhaus Standard and where care has been taken in the window installation, the energy efficiency of the Rationel window can be better than more expensive products with thermal insulation in the frames and much thicker frames.

Rationel windows have more glass and less farm than many of their competitors, because of their elegant slim profiles, giving greater solar gains, and daylight for the same size windows.

WARM, Sally’s energy consultancy firm, advises clients on how to achieve the most energy efficient buildings in the UK today. 

Sally  practices what she preaches as she has a new office and a new four-bedroomed home in a Conservation Area in Plymouth. “The choice of Rationel’s windows was crucial to us achieving our energy efficiency goals,” she explains.

Rationel Aura timber windows wit triple glazing were used, top guided, side-guided and entrance doors also from Rationel.

She adds that her house is a simple and robust design and so the house looks more traditional and doesn’t have a heat source pump or large expanses of glass.

It consists of a timber frame structure with an insulated slab for the floor and boarding on the inside and outside, creating a void stuffed with insulation, rendering the outside walls, and with weather protection in the slate cladding the upper storey.

Rationel top hung windows were used to give the opening sizes needed in a single pane and due to the lack of mullions, there is less frame and more glass.