uPVC or wood. A fair comparison.

Choose wood when the look and feel of real wood is the point of the window, or when a historic building requires it. Choose uPVC when the building has many openings, the owner wants tested performance, and nobody wants to repaint frames from a lift. Both are good insulators. The real difference is upkeep, and who will be doing it.

What wood does well.

• It looks like wood. Nothing else does, up close. Grain, depth of profile and the way it takes a finish are part of the architecture on many buildings.
• It insulates. Wood is a poor conductor of heat. A wood frame does not need a thermal break.
• It is stiff. A wood section holds its shape under load without reinforcement.
• It can be repaired. A damaged section can be cut out, filled or spliced. A tired finish can be stripped and redone in any color.
• It is renewable. Wood from a well-managed forest is a low-carbon material.
• It is what historic work calls for. Where a landmark or conservation review applies, wood may be the only frame that is accepted.

What wood asks for.

Wood lasts as long as its finish keeps water out. Paint and stain wear down in sun and rain, fastest on the south and west faces and at the bottom rail, where water sits. When the finish fails, the wood takes up moisture. It swells, the joints open, and rot starts.

On a house, that means a ladder and a weekend every few years. On a mid-rise building it means access equipment, a contractor, and an agreement about who pays. In a rental building the owner carries it. In a condominium it falls to the board. On a large building, that cycle is easy to put off.

Well-kept wood windows have lasted for generations. Neglected ones fail early. The material is only as good as the upkeep plan.

Aluminum-clad wood.

Clad wood puts an aluminum shell on the outside of a wood frame. The weather face no longer needs painting, and the room side still shows real wood. It is a good product. Two things to know: the wood behind the cladding still has to stay dry, so drainage and sealing of the cladding joints matter. And it usually costs more than either plain wood or uPVC.

What uPVC does well.

• It needs no finish. The color is either in the material, for white, or in a laminated foil. There is nothing to repaint. Cleaning is mild soap and water.
• Water does not harm it. uPVC does not absorb moisture, swell or rot. Insects have no interest in it.
• The corners are welded. The frame is one piece, with no joint to open over time.
• It is tested as a commercial window. A steel core inside the profile lets it reach commercial classes. The Vistaza Vi6 casement is rated AW-PG100 and is NFRC-certified at U 0.17 with a krypton-filled triple-pane and a warm-edge spacer.
• It is consistent. Every frame on the building comes off the same line, built to the same approved drawings.

What uPVC does not do.

It does not look like wood. Woodgrain foils exist, and from the street some are convincing. Up close they are still a printed surface. Vistaza's color list shows the solid and metallic finishes: white, black, cream, a run of grays, bronzes and brushed-metal looks. Woodgrain finishes are available by request, and availability, price and lead time are confirmed for each project.

It cannot be refinished in a new color the way wood can. Painting over uPVC or foil is possible with special coatings, but it is not a repaint cycle anyone should plan on. Choose the color as if it is permanent.

It moves more with temperature than wood does. The installation detail has to allow for that, especially with dark colors in full sun.

Side by side.

	uPVC	Wood
Look	Clean and uniform. Foil colors	Natural grain. Any paint or stain
Insulation	Good. Multi-chamber profile	Good. Solid wood
Exterior upkeep	Washing	Repainting or restaining on a cycle
Moisture	Not affected	Must be kept out by the finish
Repair	Parts and gaskets are replaced. The frame itself is rarely repaired	Can be patched, spliced and refinished
Color change later	Not practical	Easy
Historic review	Often not accepted	Usually accepted
First cost	Usually lower	Usually higher

Sound and energy.

The old argument that one frame is much quieter or warmer than the other does not hold up. Both materials insulate. For sound, the glass does most of the work and the seals do most of the rest. What separates two windows is the glass they can carry, how tightly the sash closes, and whether the numbers come from a test. Ask for the NFRC-certified U-factor and the sound test report in either material.

How to choose.

Choose wood, or clad wood, when:

• A landmark or conservation review requires it.
• The interior design depends on real wood at the window.
• The building is small enough, or the owner committed enough, that the finish will be kept up.

Choose uPVC when:

• The building has many units and one owner or board responsible for the envelope.
• Exterior access for repainting would be costly.
• The specification calls for a commercial NAFS class, a certified U-factor or a sound rating.
• The budget has to cover good glass as well as the frame.

Some buildings do both: wood on a protected street front, where the review asks for it, and uPVC on the courtyard and rear elevations.

To see what is available, look at the colors, or choose a window and see its ratings.