We can upgrade your existing timber sash windows by fitting Planitherm double-glazed units.
Planitherm units provide an excellent thermal insulation solution. We make a careful copy of your existing sliding window sash, using a good quality softwood or hardwood, but always recommend Accoya® because it is a modified, sustainably sourced timber with a durability and stability that matches or exceeds other hardwoods. We use 24mm Planitherm glass when we make your new, sliding sash windows which offers the best energy efficiency. 3mm or 4mm float glass is typically fitted in old sash windows and 24mm Planitherm glass will help your windows achieve the highest window energy ratings.
We also replace sash cords and weights with a modern spiral balance system to offset the additional weight of the 24mm double-glazed units. The spiral balance system provides sufficient counterbalance to ensure the upgraded sash windows move effortlessly. To complete the package, we fit seals and brushes to your window frames, jambs and meeting rails in order to further reduce heat loss.