I have recently upgraded the solar radiation screen which has the temperature and humidity sensor mounted inside. The Outer Plastic Container was from a toilet brush holder, you need the type that is white opaque and the plastic as thick as possible also tapered, the top is wider than the bottom. I cut out a holein the bottom to fit the inner pipe which is a piece of white plastic downspout, this forms the inner wall which was filled with liquid foam insulation. A large plastic ring was made to sit inside on top of the insulation foam. The Plastic used to make the top ring/fan plate holder and the cover outer rim ring were cut from a type of plastic which has a smooth top and bottom is sandwiched in between a very fine plastic foam; this material is commonly used for making outdoor signs (foam X) it is very easy to cut and has amazing insulation properties. The top housing has several layers of foam X and air gaps in between to form a substantial solar shield. The plastic on the outside has also been sprayed with a rubber paint to protect the outside plastic against the elements. Sensors are mounted through the side and a fan in the top draws the air through from the bottom over the sensors, it's important that the airflow does not alter the air temperature and humidity as you want them to be the same as the air in a shaded area, the fan is connected to a automated control unit which as a temperature sensor mounted on the outside, when the air temperature increases the fan will ajust the fan speed, the fan is not very powerful just enough to draw the air through the tube. Near the bottom of the tube is a nylon mesh to keep any little bugs out, the temperature and humidity sensors are now at optimum performance when it starts to rain the humidity responds straightaway, no lag time due to the efficiency of the screen and airflow.