Hi, newbie here. we've recently updated our van to a great Lunar Jupiter 5 berth, which came with a lovely NR awning. In order to respect our environment I would like to purchase a breathable awning carpet. Having looked around it's easy to get confused. There are many different makes on the market with some also selling breathable underlay. I then wondered why buy breathable underlay and breathable carpet surely the underlay does the job on it's own? and saves me a packet? Any advice / help would be greatly appreciated.