Frame options

These can affect how big your windows can be, whether double glazing can be fitted and the overall energy efficiency of your glazed areas.

Types of framing

Aluminium is a poor insulator (metal conducts heat). The most common framing material, it is light, strong, durable and low maintenance. Choose aluminium framing products with thermal breaks (which place insulation between the interior and exterior part of the frame) or aluminium combined with other materials.

Timber is a good insulator, improving with frame thickness. Although a traditional framing material, it is less durable and should be treated and sealed for weathertightness to reduce swelling and shrinkage when exposed to rain and sun. It needs regular maintenance.

Composite timber-aluminium windows are better insulators than aluminium. Aluminium sits outside and is joined to the internal timber facing with a moisture barrier. They combine durability with a timber look for inside areas.

uPVC is a good insulator made from vinyl plastic. It is light, low maintenance and steel-reinforced for strength. Because uPVC is affected by ultraviolet light, durability needs proving in NZ conditions. Manufacture of uPVC uses petrochemicals and creates hazardous wastes  - see exterior building materials for more. uPVC use is growing in New Zealand.

Steel has largely been replaced by aluminium except for fire-rated windows and heritage building renovations.

Frames and double glazing

Check the framing is suitable for use with double glazing, especially if you want large windows and doors. There may be frame size restrictions due to the weight of the glass.

Climate/weathertightness

Climate can affect the size and type of frame you can use.

If you live in a high-wind area, large windows will need to be strengthened. And if you live near the coast, choose frames that have been designed to resist salt corrosion.

Check that any windows, doors or skylights you buy are fully sealed and flashed for weather when they are installed.

Character/appearance

Colours and finishes vary with framing type - timber has many options, aluminium has a wide range of colour choices and uPVC is generally limited.

If you're renovating an older home, you may want framing sizes and types that are sympathetic to the original design - for example, wooden-framed windows on an older villa or bungalow.

Other considerations

• Can insect screens be fitted to the window frames so windows can be left open in summer?
• Do the windows or doors you want to buy have handles, locks and other hardware included?
• Are small air vents included in your window/door frames (some frames do include these which mean you can have ventilation while the window/door is closed)?