Homebuilt Stevenson Screen / Sheild

Hi peeps

I am towing with the idea about building a Stevenson Screen ( shield ), not 100% sure yet
as my DIY skills are not the best, more so when it comes to wood :oops:

  • Are the proper screens fan assisted?
  • Are the louvers specific dimensions?
  • Do they have to be a specific size?

Has anyone had any experience in building these?

  • how hard was it?
  • did you have anything to work to?

Hi Bashy

This could be a start http://www.hereford-weather.co.uk/html/StevensonScreendiy.htm


Cheers Steve, thats just the ticket, Although no mention of a fan
I would have thought in the sun it would attract some sun heat due to the size of them
more so if there is no wind?

Bashy - I have fitted a fan to the top of my insulated screen - not a vented/louvred one yet, and used plumbing piping to run the suction down over the top of the sensor, up and out of the top (with silicon sealant) and over and down again beside it with a fan in the outside section - it needs to vent down below the normal level of the unit or up with a weather protection hat? I am currently using a solar educational kit with a fan but will progress to a PC fan ruinning at 5 or 6 volts. The photos of mine are in the Siting and Installation Tips board. Temporary and for a trial mind you… :wink:


Any further thoughts anyone?


Cheers for the reply :slight_smile:

I did see your thread when you started it and found it most interesting :slight_smile:
I on the other hand went for the more traditional method as you know.

As it was really a bodge job and had every intention of remaking mine before
the spring time, i thought of the idea to make the real McCoy so to speak

I have done some searching on the net for the screens but none that i have found
so far have a fan in them and i am a little baffled as to why not?

If you have a good amount of time to spend on it then it will be fine, but really, dont rush it. I did on my first attempt and it went horribly wrong, my second attempt (taking alot of time preparing, marking holes etc) went very well. Although i ditched it a while back and now have my 1 wire temp sensors in micro protective screens (plastic) that i built. This is becuase they can be put on the north facing part of my house which never sees any insolation, if i had put a circular screen up then it would be an eyesaw in that position.

I personally would build a met office spec screen, if i had the time and space for it.

That is what i am really after, although i have just read the the walls, floors roof and bottom are double
perhaps this is why no fan is required due to the double shielding?

As for taking my time, i always have every intention in doing so, but then i try to get
it finished as soon as then things tend to go pete tong on me :oops:
thats what happened on the FARS i made, granted, its doing its job, but looks untidy
oh and the filler still aint gone hard yet #-o

Sounds Familiar :wink: .

Imo a Met office screen is much better, as there is a great deal of distance from the nearest insolation heated material to the sensor / instrument but these are obviously much bigger and for an urbanite like me i just dont have the space. If you had a very large unobstructed garden then these will work otherwise there not that benifical.


I thought I remembered old thread about this, and I found it. Follow the first link in this post then look for Stevenson Screen on his menu and you’ll get to a .zip download of a scan that Windy did some years back of some actual plans. There’s some other good info in that short thread too.


  • Jim

Here is another link of interest maybe? http://www.metspec.net/products.html


There are other threads/posts on here indicating that (at least in the US) the passive Stevenson is yesterday’s technology and many official sites now use aspirated shields.

Indeed in the states aspriation is a must, but over here in the U.K due to a high average wind speed on most days of the year and a cooler climate, we only really need aspiration in our shields say on average 2 days of the year where we get the highest temps on the calmest days. Otherwise it doesnt really make much difference over here for the rest of the year, so the need is low.

Here in the UK it is the preferred method, well according to our Met Office, What do the US
Met officials use Niko?

Cheers for the links guys, appreciated, although i think Brians link is now dead…
I am still undecided as to what to do yet, I could try to make one, or buy a cheap
one from The Weather Shop (about 40 quid when in stock) or attempt another FARS
I have a month or 2 to come up with something :slight_smile:

I knocked one up using a louvred panel from Focus DIY and aspirated it with a 12v .09A computer fan run by a solar panel.

Search might bring up some earlier links but this is one:


i think Brians link is now dead...

The second link in that post is still active, and then on the menu at the left of that page is a link to the screen plans (and a great picture). :wink:

I made one of these,many years ago now :wink:, and yes they are a bit tricky to build. All the slats and all the saw cuts you will need some good clamps too. The painting not as straight forward as you would think.

But don’t let this put you off :lol: You could still probably make it cheaper than the official ones with the black insides. Good luck.

Here’s one vendor:



Just found a link to my first post ref homemade screen


I later found aspiration improved things even more

Here is my homemade screen that was easy to construct.
Its almost maintenance free and never needs painting.


That is both impressive and interesting…food for thought for the future…Thanks for sharing the construction methodology :slight_smile: