PVC or aluminium windows for a Spanish new build: compare the complete opening

For a new home in Spain, the useful comparison is not “PVC versus aluminium” in isolation. It is one complete window against another in the same opening. Size, opening mechanism, glass, shading and installation can change the result enough to make a material-only comparison misleading.

Start with how you intend to use each opening: a bedroom window, a kitchen window above a worktop and a large garden door are different purchases. They do not have to share every detail merely because they belong to the same house.

What the frame choice changes

PVC profiles and aluminium systems offer different geometry, reinforcement and finish options. Thermally improved aluminium uses a thermal break to interrupt the metallic path through the profile. Guardian’s overview of frame materials explains this distinction. The phrase “aluminium window” alone does not tell you whether that feature exists.

Neither material label establishes a universal level of performance. Product series differ, and the completed window depends on its size and configuration. A narrow visible frame or a particular large-opening solution may be valuable in one room, while another opening has simpler requirements.

In Spanish quotations, carpintería exterior means the exterior window and door package; it does not imply timber. Ask for a window schedule showing the exact series and configuration for each opening rather than accepting a general description for the whole house.

Read the thermal numbers in the right order

U-values describe heat transmission for a temperature difference. Lower values mean less transmission under the same conditions. Ug commonly describes the glass, Uf the frame and Uw the complete window. The CTE envelope calculation document accounts for the glazing, frame and their junctions rather than treating one component as the whole opening.

This matters when a quotation prominently displays an impressive Ug. The completed window will not necessarily have the same number. Ask what window dimensions and configuration the reported Uw covers, especially when the house includes very different sizes.

Choose the opening mechanism around the room

A fixed pane can provide a clear view but cannot open for ventilation. An inward-opening sash needs space inside the room; a sliding arrangement changes how the passage and tracks work. These practical differences should be settled before comparing price.

Imagine a kitchen with a tap immediately behind the window. An attractive inward-opening design may conflict with the tap or items on the worktop. Moving to another opening type changes the specification, so compare the revised products rather than continuing with the original prices.

For terrace doors, consider clear passage and the threshold detail early. The external paving level, drainage and accessible route need coordination. The headline opening dimensions do not describe all of those interfaces.

Give the glass and shading their own decision

The frame material does not decide solar gain. A large west-facing window and a shaded north-facing opening can need different treatment. Compare the glass specification and the planned shading alongside the frame, using our guide to double and triple glazing for that part of the choice.

Spain’s CTE DB-HE addresses energy performance and solar control at building level. That is why a good insulating figure should not be interpreted as proof that a room will remain comfortable under strong sun. The project assessment needs the actual orientation and surrounding conditions.

For context, take a hypothetical 15 m² window package with Uw improving from 1.6 to 1.1 W/m²K. At a fixed 15 °C temperature difference, the reduction in heat transmission is 112.5 W. This is an instantaneous illustration, not annual energy savings. It cannot establish payback without a much fuller building and usage model.

Price the connection to the building

A window is tested as a product, then installed into a wall built by other trades. The quotation must allocate the perimeter connection, sills, reveals and any shutter-box interfaces. A product can be suitable while the purchasing scope leaves those jobs unresolved.

The installer and façade contractor should work from compatible details. Decide who measures the completed opening, when manufacturing dimensions become final and who deals with an out-of-tolerance opening. These questions belong in the construction drawing package before the order is released.

If you are pursuing Passive House performance, installation details will be particularly visible in the design process. Their importance is not restricted to certified projects, however: every window needs a coherent connection to its wall.

Compare the financial upgrade you are actually buying

Request like-for-like alternatives by window, with supply, installation, shading equipment and finishing identified. An offer that excludes installation cannot be ranked against one that completes the opening without adding the missing work.

Consider an invented comparison: option A is €700 supply-only, plus €160 installation and €90 finishing; option B is €920 for the same agreed scope. The comparable totals are €950 and €920. These are demonstration figures, not Spanish market rates. Their purpose is to expose the effect of scope.

The materials quotation guide helps organise those entries. Place the final decision within the complete house budget so the money addresses the rooms and performance goals that matter to you.

Tell us about the window package for your Spanish home. Include the municipality, available schedule, approximate dimensions and preferred opening types. Mention which rooms have strong sun or particular access needs so the enquiry reflects how the house will be used.