Product Review: Dometic / Seitz S4 Motorhome & Caravan Windows

Disclosure: I paid for the windows shown in this review myself and have no relationship with Dometic/Seitz or its UK distributors. Links marked with (eBay⇒) or (Amazon⇒) are affiliate links. This means I get paid a small commission if you buy something after clicking on the links. This money helps to pay for the running of the website.

As anyone who has read my review of my own DIY conversion will know, I am a big fan of Seitz S4 windows. In this review, I will explain what they are and why I rate them so highly.

Motorhome Windows – An Introduction

Motorhomes are a bit like houses, in terms of window technology. Once upon a time, the only option was single-glazed glass windows. As anyone who has lived with them knows, these provide very little insulation or heat retention, are prone to condensation and tend not to be very secure.

Sealed-unit double-glazing technology changed house windows forever, and motorhome and caravan windows have undergone a similar transformation.

Most motorhomes and caravans these days come with acrylic, double-glazed windows, often with built-in fly screens and roller blinds. These offer hugely-improved thermal insulation, better security (often) and remove the need for curtains.

Some of the best of these windows are made by Seitz, one of the brands owned by Dometic, which makes a lot of caravan and motorhome equipment.

Note: Although all caravans and coachbuilt motorhome conversions come with these double-glazed windows, many panel van conversions do not. Instead, they come with single-glazed, glass vehicle windows – of the type fitted to minibuses. I have no idea why this is – I have had a van with glass windows of this kind and they are deeply inferior to proper motorhome windows. The idea of paying £30k-£40k for a new motorhome with minibus windows seems crazy to me – would you buy a new house with single-glazed windows?

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Seitz S4 Windows

Seitz make a range of leisure vehicle windows. Most of these are only available to motorhome manufacturers, but the S4 range is widely sold by motorhome parts suppliers and is ideal for the self-build converter. Seitz S4 windows offer the following features:

• Tinted, sealed-unit double glazed window panes
• Built-in fly screens and heat-reflective roller blinds
• Reasonably good security and the ability to lock the window in a ‘slightly open’ position
• Simple, robust fitting to most panel van and coachbuilt bodies

Fitting Seitz S4 Windows: I have documented the fitting of these windows in my DIY conversion guide. Click here to see an illustrated account of fitting one of these windows to a panel van. In short, fitting them is reasonably straightforward.

In Use: In use, the S4 windows are excellent. They provide insulation in both hot and cold conditions – preventing the living area of the motorhome heating up like a car would in hot sunshine and preventing an instant drop in temperature when the outside temperature falls. Obviously this is subject to the rest of the body of your van being insulated, too.

Our S4 windows are top-hung – meaning that they open outwards, hinging along the top of the frame. Sliding models are also available. The built-in fly screens mean that you can leave windows wide open without having to worry about insects getting trapped inside the van. The only exception to this (in our experience) is that the mesh on the fly screen is large enough to allow Scottish midges to crawl through it quite easily.

The built-in roller blinds are excellent and provide a complete blackout, if desired. They also have an aluminium coating on the outside, providing additional insulation in both hot and cold conditions. The runners for the blinds have intermediate stops – so they can be partially rolled up for privacy yet still admit some light. The blind and the fly screen can be clipped together so that they provide complete coverage of the window yet still allow light and air through.

Final Thoughts

We fitted two Seitz S4 windows to our motorhome, and after more than 14 weeks away and two years’ use as an everyday vehicle, we are very happy with them. They appear to be well made and are still as smart and easy-to-use as they were when they were new.

If you are thinking of converting a panel van yourself, this type of window does not cost much more than a minbus-type bonded or rubber-mounted glass window and offers much better insulation and security for living accommodation. The only downside I can see is that due to the width and thickness of the S4 window frames, you may not be able to fit quite such large windows as you could with glass windows.

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