Motorhome Thermal Blinds in 2019 – Internal or External, Which is Best?


Hi, I’m Chris, I run Horton Common along with my father Robert.

When I arrive on-site to meet our guests who turn up with a motorhome I sometimes come across them fitting a thermal blind over the front of their cab. I’m writing this post towards the end of the camping season when the temperatures are dropping. So obviously guests are fitting thermal blinds on their motorhome to keep the heat in at night. However, I will also find several guests fitting thermal blinds to their motorhome cabs during the peak of summer. In the summertime, their use is obviously not to keep the heat in but the sun out. Some of our guests fit the exterior thermal blinds, others fit the interior blinds. So for today’s post, I thought I would reference some fo the feedback I’ve received from guests about what type of thermal blind they’ve found the best, their pros and cons and do you really need one?

Motorhome Thermal Blind

As an example, Milenco offers both internal and external thermal blinds for motorhome cabs. But which do you choose?: Image – Amazon

There are more variables to consider when choosing the right thermal blind for your motorhome that you might think. Definitely more than I originally thought. Size and weight considerations with regards to storage, ease of use, condensation, privacy etc. These are the key considerations and differences when it comes to choosing either an external or internal motorhome cab thermal blind.

Introduction to Motorhome Thermal Blinds

When I write posts for our website I want them to be as helpful as possible. So you find the information you’re looking for and hence you might consider coming to pay us a visit here at Horton Common. While the feedback I receive from our guests on their experiences is the foundation for how I write these posts, I also do additional research beforehand. Where possible I like to reference a video or two. Case in point for this post on thermal blinds I think you should give the video below from Practical Motorhome a quick watch. Its less than 5 minutes long but it covers the key factors to think about when it comes to insulating the cab on your motorhome.

If you’re thinking of purchasing thermal blinds as insulation for your motorhome I would encourage you to watch this video.

Motorhome Window Types (Glass/Acrylic)

So as John references in the video, the windows on your motorhome which I’m sure you have noticed are made from different materials. The rear and side windows are typically made from acrylic plastic. With regards to winter, these acrylic windows have a much better thermal performance than the safety glass on you cab windscreen and door windows. You can improve the thermal efficiency in winter further behind these acrylic windows but using thermal backed curtains and concertina blinds.

The emphasis of today’s post though is insulating the safety glass used on your motorhome cab for the windscreen and door windows. In the winter this glass conducts the heat away from your living space and during the summer it lets solar radiation in which cannot easily escape. Hence the temperature in the motorhome can rapidly rise. In the summer months, your motorhome windscreen can particular be a problem. Not only due to its significant size but due to the fact its angled up towards the sky. So the windscreen typically captures more solar radiation than your side windows.

Internal Motorhome Cab Thermal Blinds

I’ve seen our guests fit both internal and external thermal blinds to their motorhomes. Each has its pros and cons which I’ll now discuss. When it comes to internal thermal blinds they typically come with suction pads mounted to them that you have to secure to the inside of the windscreen. As such, it can be frustrating if those suction pads keep falling off. You may have had this issue before with portable Sat Nav units for instance. To make sure the internal thermal blind stays in position its not only important that is has a sufficient number of suction pads but that the pads and surface are really clean.

Internal Motorhome Thermal Blind

Its not just Milenco who produce internal thermal blinds, Maypole (pictured) also have their own product: Image – Amazon

If there is grease and dirt on the windscreen surface suction pads will often fall off. Get a cloth (I find microfibre cloths the best) and use some good quality window screen cleaner or methylated spirits. In the past, I had the frequent issue of my Sat Na falling off the windscreen. After cleaning the glass it made a huge difference to how well the suction pads gripped the glass.

The downside with internal thermal blinds which our guests have informed me of is they don’t help with condensation. With the thermal blind fitted on the inside of the glass, the glass itself is still getting cold during winter nights. Therefore the warm humid air from inside your motorhome reaches the glass and condenses. Our guests have informed me that on many occasions when they remove an internal thermal blind they have to wipe down the windows to remove the condensation.

External Motorhome Cab Thermal Blinds

So unlike internal thermal blinds, external blinds are much better at stopping condensation forming on the inside of the windscreen. The reason being, in this case, the windscreen glass itself is kept much closer in temperature to the internal environment of the motorhome. To fit an external thermal blind you have to lift up the window wipers. Then fold out the blind and fit it across the windscreen. There are velcro tabs which you undo and wrap the blind around the wing mirrors and secure the velcro back into position. External blinds have much more padding (insulation) than internal blinds. This does mean therefore they generally have better thermal performance, but that does come with a downside as discussed below.

External Motorhome Thermal Blind

This is an example of Milencos universal external thermal blind. Though there are lots of other products on the market: Image – Amazon

The downside with external thermal blinds is their bulk. That additional insulation padding means you cannot fold them up as small as an internal blind. So it will take up more storage space within your motorhome as well as taking more effort to fit. The other problem is potentially the wind. Some do come with suction pads to help to try and keep it secure to the windscreen. Furthermore, the velcro around the wing mirrors should help to keep it in place. However, if the wind is lifting the thermal blind off the surface that means its thermal performance is reduced.

Conclusions on Thermal Blinds for Motorhomes

I have also spoken to some guests who used to use thermal blinds but decided they were a ‘faff’ and didn’t provide sufficient benefits to justify the effort of fitting them. There does appear to be a bit of a love them/hate them attitude with many motorhome owners over the use of thermal blinds. In the summer months though during the peak hours of the day I do think anyone without an air conditioning setup is going to appreciate the benefit of their thermal blinds.

There is no simple answer in terms of which is best, internal or external thermal blinds. They both have their strengths and weaknesses. If you don’t like the potentially ‘baggy’ fit of universal off the shelf thermal blinds there are companies that will make blinds to custom fit your motorhome. However, you will obviously have to pay a premium for such products. Typically double that of the off-the-shelf products.

I hope you found this post useful, you may also be interested in some of my other posts, such as how to properly level a motorhome. I also hope you consider coming to visit us here at Horton Common in the near future to experience our fully serviced pitches. 🙂

Chris - Site Manager

Hi, I’m Chris, I along with my father Robert we operate and maintain Horton Common.

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