Windows
You could reduce the overall weight of your van by considering the amount or size of the windows that you put in to your build (glass is pretty heavy)
Windows are great for allowing light in to the space and bringing the outdoors in, but they can also cause a number of issues including condensation, heat loss, or even too much heat on those hot days, where many windows in a van can make it feel like a green house!
Batteries & Solar
Lithium batteries are the real deal when it comes to van builds and can be far lighter than other batteries on the market, however, be prepared, as it is not just the van that is going to be a lot lighter - your wallet definitely will be too! (all be it a very good investment)
When considering solar we are a huge fan of flexible solar panels, you can save a considerable amount of weight here, for example a standard 160w solar panel can be around 15 - 20kg as apposed to a flexible which are around 3-10kg depending on brand. Flexible panels can be a controversial subject in van conversions, however if mounted correctly with adequate ventilation there should be no cause for concern!
Walls & Ceiling
Consider using a lightweight alternative to wood, for example, we use hollow soffit cladding quite often, we discovered this on the off chance as Wayne had lots left over from a housing project
(this type of cladding is typically used for the outside of buildings)
We continued using it mainly because it is very light compared to wood but also has many other benefits:
Light weight & long lasting (won't swell or bow like wood)
Easy to clean and waterproof
The hollow core creates another cavity providing better insulation properties
Available in long lengths
No screw holes visible
No sanding, painting or staining required
In the UK,
Eurocell
is a great brand for this type of cladding. Although they are selling plastics with in the building industry, this company does care about the environment, and the steps they are taking to ensure this went a long way for me when choosing a supplier of this product.