Fibreglass windows offer much less insulation than vinyl windows. PVC windows are designed to trap pockets of air and thus are very efficient in keeping out cold. Fibreglass offers to up to 3 times less insulation than vinyl. So if you are looking for insulation your choice has to be vinyl windows.
Fibreglass is composed of glass fibres and resins which are better able to expand and contract as the weather changes allowing it to maintain its integrity. This makes fibreglass windows ideal for hot climates or climates with extreme temperature fluctuations
Fibreglass windows are relatively durable – they resist rotting, warping, and cracking – but will need routine painting to maintain their colour and appearance..
Vinyl windows are a great option if you are a low-maintenance person.
They are rust resistant, impervious to bugs, and don’t warp or peel. With some minimal bi-annual maintenance, your vinyl windows will be good to go
Fibreglass windows are made from sand and composite replacement windows are made from sand and wood pulp left over after manufacturing of wood windows. That makes them more Eco-friendly than vinyl, a petroleum-based plastic.
Vinyl is recyclable.