different types of window frames


If you’re deciding to replace your windows or you’re choosing windows for a new build project or renovation, you’ll need to consider which window frame material is right for you and your home, be it wood, uPVC, aluminium, aluminium clad or aluminium timber composite windows.

To help you choose we’ve highlighted 5 of the most popular types of window frames available and their benefits:

Group windows Isolated on white background


Wooden windows are available in a range of hard and soft woods, with differing costs and benefits. They can be manufactured as ‘made to measure’, based around a standard set of profiles or systems, or fully ‘bespoke’ which are manufactured as a complete one-off design and size. They can be manufactured from FSC timber and fitted with sealed units to benefit from the energy efficiency that double-glazing brings.


  • Authentic real wood look and feel
  • Softwood can be cost effective, but won’t last as long as hardwood
  • Can be stained or painted in a colour of your choice
  • Suitable for modern or traditional homes
  • Environmentally friendly and good thermal insulation
  • Hardwood can last longer than other window frame materials, up to 60 years.


  • High maintenance – will need regular repainting/treating
  • Hardwood can be expensive, but benefits from extended longevity compared with softwood
  • Softwood will need replacing more regularly than hardwood (due to it being exposed externally)
  • Tendency to absorb moisture and warp and twist during the drying out process


Plastic windows are often a popular choice due to their affordability, and are now available in a range of colours and finishes achieved with either spray paint or foil laminate.  Some of the less costly plain white plastic windows can look less attractive and may degrade faster than the more premium coloured foil laminated options. When looking at uPVC window systems, there is a huge difference between the standard white ‘budget’, characterless uPVC windows and the more premium uPVC systems where there is a considerable choice of colours, finishes and styles – even suited to period properties. As with anything you need to compare the options and costs to find a solution to fit your needs.


  • Can be the most cost effective solution – although the plain white versions with little character may not be the most aesthetically pleasing
  • Low maintenance
  • Wide range of colours available
  • Custom sizes
  • Cost effective solution for replacement window market – some have been designed specifically for period properties
  • Section depths make installation on replacement windows straight forward
  • Availability to customers and ability to drive the price down, due to this


  • The plain white options can look cheap
  • Can degrade and not easy to repair
  • Are less environmentally friendly than alternatives
  • White windows can discolour
  • Saturated product
  • Manufacture size limitations
Different types of window frames


Aluminium is a very common type of window frame, suitable for modern properties, and often used in commercial applications such as curtain walling.

It is becoming more popular with residential projects as a good alternative to uPVC market. As with uPVC there are big differences between the budget entry level aluminium windows and the high-end options, so you need to do your research.


  • Can be cost effective if the lower end entry level option is chosen
  • Low maintenance
  • Slimline frame
  • Triple glazing options
  • You can fit your entire home with the same system (i.e. windows, bi-folds, doors, entrance doors, rooflights etc.)
  • The system can typically provide larger panels, with multiple options


  • Can have a more clinical feeling internally compared to wood
  • Typically issued in profile/kits and fabricated in the UK by ‘approved installers’; which negates some of the selling points (i.e. Made in Germany etc.)
  • Likely to be the coldest element inside your house, therefore air moisture is still likely to form on this area


Aluminium Clad Windows were the first incarnation of what we now know as ‘Composite Windows’ (see below).

The majority of Aluminium Clad Windows started off life as an all-timber window, with an aluminium profile fitted to the front of the window to improve its longevity. This creates a gap between the aluminium and timber, allowing air and therefore moisture and dirt to penetrate the timber, thus requiring it to be treated with environmentally unfriendly anti-rot chemicals.

(Please note: Composite Windows are often referred to as ‘Aluminium Clad Windows’ so it’s best to check with your window supplier on the actual window construction). For further reading take a look at our Advice Centre article: COMPOSITE VS ALUMINIUM CLAD WINDOWS


  • Marginally extended lifespan compared to softwood timber windows
  • Some systems offer equal opening and fixed sightlines


  • Timber section is indirectly exposed – aluminium needs to be removed periodically so the timber section can be refurbished to maximise life of window
  • Timber needs treating with environmentally unfriendly chemicals to extend life
  • Some systems require additional add-ons to install cill flashing and/or install in a rendered or an external clad situation.


True composite windows have a unique bonded construction consisting of an outer part of stylish aluminium, powder-coated in a colour of your choice, and an inner part of wood which can be finished in natural clear lacquer, stained or painted in your chosen colour.

These two parts are divided by a high performance butyl tape, compressed to eradicate air and thus prevent the risk of condensation. This means that no timber is exposed externally, for a longer lifespan and minimum maintenance. (Please note: composite windows are often described as aluminium clad windows, aluminium composite windows, alu clad windows and aluminium wood windows).


  • Best of both worlds – aluminium outer combined with warm wood internally
  • High performance in harsh weathers
  • Excellent energy efficiency
  • Low maintenance powder-coated aluminium exterior (no repainting)
  • Warm, authentic wood feel interior
  • Long-lasting, cost effective for the future
  • Bespoke sizes, styles and colours to suit your project – view finishes available on our STYLES & OPTIONS page
  • Excellent acoustic properties for high noise pollution areas
  • Constructed of fully recyclable materials
  • Designed as a true composite construction with the equal balance of aluminium and timber


  • Can be seen as more expensive, but will last longer than cheaper alternatives (up to 40-50 years according to industry professionals) and, with occasional cleaning, will stay looking good for years to come
  • Manufacturing and weight limitations compared to other materials.
  • Suitability of door products in high-traffic locations.
  • Typical frame thickness makes the replacement of windows into existing openings more difficult.
triple glazed composite windows oak aluminium corner
Westcoast composite windows, doors and sliding doors are constructed of an outer part of aluminium bonded to an inner part of wood. The aluminium exterior is low maintenance and can be powder-coated in a colour of your choice. The warm wood interior can be pine, oak (shown here) or a timber species of your choice, finished in lacquer, stain or painted in your chosen colour.
oak composite windows

For more information about Westcoast composite windows and doors visit our pages MADE IN SWEDEN and STYLES & OPTIONS.

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