Sliding vs Push Windows for Camper Conversions

Choosing the right windows for your campervan conversion affects comfort, security, insulation, and the overall quality of the finished build. The two dominant window types used in conversions — sliding windows and push-out (hinged) windows — both have distinct advantages, and the best choice depends on your van, your build style, and how you use the vehicle. This guide covers both types in depth, including brand recommendations and installation considerations relevant to the UK, German, and Dutch campervan markets.

How Each Window Type Works

Sliding Windows

A sliding window consists of a fixed outer pane and an inner panel that slides horizontally to open. The sliding section runs along a track, either rubber-sealed or with a brush seal, and typically opens to give roughly 40–50% of the total pane area as ventilation. The opening mechanism is simple and durable — there are few components that can fail. Sliding windows sit flush with the van body when closed, giving a neat, low-profile finish.

Push-Out (Hinged) Windows

Push-out windows, sometimes called tilt windows or hopper windows, are hinged at the top (or occasionally the bottom or side) and pushed open from inside, either by hand or via a stay mechanism. When open, they project outward from the van panel. The full pane area can potentially act as a ventilation opening, which allows greater airflow in some designs. Higher-end push-out windows from brands like Seitz and Dometic use a worm-gear stay that holds the window at any position, allowing fine control of the opening angle.

Ventilation Efficiency

For passive ventilation — drawing fresh air through the van by temperature differential or wind — push-out windows have a slight edge because the full pane can act as a scoop or deflector, directing air into the van regardless of wind direction. The angle of the open pane can be adjusted to catch or redirect airflow.

Sliding windows provide a more predictable, horizontal ventilation slot. In practice, for most campervan applications, the difference in ventilation performance between a quality sliding window and a quality push-out window is marginal. What matters far more is the position of the windows in the van and whether a roof vent provides the through-flow to complement them.

Security

Security is a genuine concern for campervan owners in urban environments or when wild camping in unfamiliar areas. Sliding windows are generally considered more secure: the sliding panel can only be opened from inside (or with a key in lockable variants), and the locking mechanism is straightforward. There is no external lever or hinge to attack.

Push-out windows require a more careful assessment. The hinge and stay mechanism is typically on the inside, which is good. However, some budget push-out windows can be forced from outside by applying pressure to the pane. Quality push-out windows from Seitz and Dometic use robust locking latches that are resistant to forced entry. Always check the specific model's security rating rather than assuming the window type is inherently more or less secure.

For either type, secondary security can be added using internal security locks or steel cable ties, which are particularly popular with full-time vanlifers in cities.

Condensation and Insulation

Single-glazed windows — whether sliding or push-out — are a significant weak point for condensation and thermal performance. A cold window pane in winter acts as a condensation surface, creating damp patches and potential mould problems. Single-glazed windows also lose heat rapidly by radiation.

Double-glazed windows address both issues. The sealed air gap between the two panes dramatically reduces heat loss and keeps the inner pane surface warmer, greatly reducing condensation. Both Seitz and Dometic offer double-glazed options for their van conversion window ranges. The additional cost (typically 40–80% more than single-glazed equivalents) is well justified for a van used year-round in the UK, Germany, or the Netherlands, where cold, damp conditions are common.

Some converters fit single-glazed windows and then add internal insulating film or acrylic secondary glazing panels. This is a workable solution, though it adds complexity and the aesthetic is less clean than a purpose-built double-glazed unit.

Brand Overview

Seitz (Dometic Group)

Seitz windows are the most widely used specialist van conversion windows in Europe. Originally a German company, Seitz is now part of the Dometic Group. Their S4 and S7 series are available in a wide range of sizes and include sliding, push-out, and fixed variants. Double-glazed options are available across the range. The S7 series features a particularly clean frameless appearance and is popular in high-specification builds.

Seitz windows are available in standard cut-out sizes that have become industry norms in Europe, making sourcing and fitting straightforward. Replacement seals and parts are widely available.

Dometic

Dometic's own-brand windows (distinct from Seitz, which sits under the same parent group) are targeted more at motorhome OEM applications, but several sizes and types are used in custom builds. Dometic Midi and Rollo windows are popular choices for rear conversion areas where a large, well-sealed window is desired.

Carbest

Carbest is a German brand sold primarily through the Reimo campervan accessories network and popular in continental European builds. Their windows are competitively priced and available in an unusually wide range of standard and non-standard sizes. Carbest windows are frequently used in German and Dutch van conversions where builders want a cost-effective solution without sacrificing functionality. The double-glazed Carbest Flex window is a well-regarded option for the price.

Size and Placement Considerations

Van conversion windows are typically cut into the steel panel between the van's structural ribs and pillars. The maximum window size is constrained by the rib spacing on your specific van model. Before ordering windows, measure the available panel width and height carefully, accounting for the required overlap of the window frame onto the surrounding metal.

Common conversion window sizes are:

• 900 × 450 mm — a popular mid-size for the main living area panel
• 700 × 400 mm — suitable for narrower panels or a secondary window
• 400 × 250 mm — used for small lights or toilet compartment ventilation

On a standard wheelbase Volkswagen Transporter T6, Vauxhall Vivaro, or Ford Transit Custom, the sliding door panel typically accommodates one 900 × 450 mm or 700 × 400 mm window. On long-wheelbase vans, there may be two separate panels, each accommodating a window.

Installation Considerations and Price Range

Fitting a window to a van is a significant undertaking that involves cutting a clean rectangular hole in the steel body panel, removing any internal insulation or trim around the opening, fitting the window into the aperture, and sealing it correctly. The window frame is typically bonded to the outer body panel using butyl tape and/or adhesive sealant, with the inner trim ring securing the assembly from inside.

Key installation points:

• Use a proper step drill and jigsaw with a fine metal-cutting blade. Cutting speeds are critical — too fast generates heat that discolours the paintwork.
• Treat all exposed steel edges immediately after cutting with zinc primer or anti-rust paint to prevent future corrosion.
• Butyl tape is the primary seal between window frame and body panel. Apply it evenly around the entire perimeter without gaps.
• Allow the adhesive to cure fully before driving — typically 24 hours for body adhesive sealants.
• Always check that window fitting does not compromise the van's structural integrity at pillars or load-bearing points.

Price guide for conversion windows (per window, supply only):

Type	Brand Example	Single-Glazed	Double-Glazed
Sliding window (900 × 450 mm)	Seitz S4	£120–£180	£200–£280
Push-out window (900 × 450 mm)	Seitz S7	£150–£220	£250–£350
Sliding window (700 × 400 mm)	Carbest	£80–£130	£140–£200

Which Window Type Should You Choose?

For the majority of custom conversions, a sliding window is the most practical choice. The mechanism is simple, reliable, and proven. Seitz S4 double-glazed sliding windows represent the best combination of quality, parts availability, and price for UK and continental European use.

Push-out windows are worth considering if your build prioritises aesthetics and you are willing to pay a premium. The Seitz S7 in a push-out configuration gives an exceptionally clean external appearance and is popular in high-end builds. They also have a slight functional advantage in directing airflow from certain angles.

Regardless of which type you choose, invest in double-glazing if you plan to use the van in autumn and winter. The improvement in comfort and condensation management is substantial.

Frequently Asked Questions

Can I fit a caravan window to a van?

Caravan windows are designed for thin GRP or aluminium composite panels, not steel van bodies. The frame depth, bonding method, and seal type differ. It is possible but generally not recommended — use windows specifically designed for vehicle body fitting.

Will cutting a window void my van warranty?

Modifications including window cutting will typically affect the manufacturer's structural warranty for the affected panels. Check with your van manufacturer or insurer before proceeding, and document the conversion professionally.

How do I stop my campervan windows from steaming up overnight?

Condensation on windows is caused by warm, humid air inside the van meeting the cold window surface. Double-glazing reduces (but does not eliminate) the problem. Maintaining adequate ventilation — a slightly open roof vent — allows moisture-laden air to escape before it condenses. A quality vapour barrier in your insulation also reduces the overall moisture load in the van.

Do I need planning permission to convert a van with windows?

In the UK, no planning permission is required to convert a van for personal use. However, if the vehicle is type-approved as a commercial vehicle and you are altering it, there may be implications for its Vehicle Identification Number (VIN) category. Seek advice from a registered conversion specialist if you are unsure.

What is the best sealant for fitting campervan windows?

Butyl tape (such as Würth butyl sealing tape) is the preferred primary sealant for the frame-to-body interface. For the outer edge joint, use a UV-stable, paintable polyurethane body sealant (such as Sika 227 or equivalent). Do not use silicone — it is difficult to paint over and degrades faster than polyurethane in exterior applications.

Browse our range of campervan windows at Eurovan Shop.