Having lived with all three types of windows and patio doors in the past three years, I feel that I am an 'expert user' when it comes to opening and closing in each medium: wood, pvc and aluminium.

First, the novice's choice: wood. It looks great, feels warm, can be stained a medium or dark shade or painted any colour of the spectrum. It's an age-old medium so what can go wrong? The main problems are humidity and strong sunlight.

There are varying qualities of wood on offer, depending on your budget. A moderately-priced pair of French doors on a south-facing house wall suffered a degree of warping, creating gaps that had to be plugged each winter in an attempt to keep the cold draughts at bay whereas, in warmer damp circumstances, the door had to be forcibly pushed and pulled back into its aperture.

Two good summers and the four coats of varnish had virtually vapourised, revealing cracking wood that needed nourishing and protecting from the next couple of years' weather.

Second, the double-glazing salesman's special offer: PVC. Overpriced by a couple of well-known companies who then discount by 50% if you hesitate, PVC is also available in varying qualities. At the higher end of the market, the frames are often reinforced with metal.

Generally with more features than wooden doors and windows, PVC should not require much more than a quick wipe with a damp cloth for the first few years and its looks are therefore easier to maintain. We have some PVC French Doors from the lower price range. As value for money, they are quite good but an element of trust is lacking in terms of defence against determined intruders. They feel floppy and flimsy when opening and closing and there's a knack to locking and unlocking them successfully. We have older PVC doors from the higher price range and, whilst more sturdy (reinforced with metal) they are looking a tad ratty.

The PVC windows screeched with wind whistling through, like semi-detached tinnitus.

Thirdly and finally, the long term investment: powder-coated aluminium frames. If you are fed up with sanding down wooden frames and considering the easy option of PVC or coated aluminium, particularly for a wide opening with multi-folding doors. Consider whether PVC is up to the task of substituting for the wall of your house.

Stand back and look through closed doors at the difference between PVC and aluminium - it is very noticeable. With PVC, there are windows of scenery between wide areas of plastic (two frames together might measure between 8 and 10 inches, 20 to 25cms) so the doors block up to 20 per cent of the potential view and light-source.
 
Aluminium frames on bifolding doors from manufacturer SunSeeker Doors, being stronger, are only about 2 inches or 5 centimeters. The profile is also considerably smaller so the doors use far less space than PVC or wood when folded back. For those who want color, several options are available to order, the most popular (after standard white) are: Grey, blue, green, brown and silver. Aluminium Frames are more expensive than cheap PVC or wood but prices are comparable with the better quality PVC doors. Is aluminum worth the extra cost? If you want the "wow" factor, strength, longevity, maximum living space and the most panoramic view,Yes.