Aberavon Since its creation, uPVC has moved to the top of the list of the most popular materials for both doors and windows around the country. So what exactly is uPVC and why should you choose a door made from it? uPVC (unplasticised polyvinyl chloride) is a lightweight but strong plastic that’s used in construction. The fact that it’s much easier to maintain than wood and holds its strength over time means it’s a brilliant material for both doors and windows. There’s no need to constantly reapply paint and varnish to keep the door waterproof, your uPVC door will stop whatever the weather throws at you! On top of that, uPVC is an excellent insulator, helping to keep heat inside your home and saving you money on your energy bills.