Royal Belgian Meteorological Institute proves "The New Standard in Air Temperature Measurement is the BARANI helical MeteoShield"

Barani MeteoShield Pro looking over a Stevenson screen meteorological shelter

Following a long-term study by the Royal Belgian Meteorological Institute the results of the performance of the patented design of the MeteoShield Pro, on which the MeteoHelix IoT Pro micro weather stations are based, were finally published at on October 08, 2018 at the CIMO-TECO-METEOREX - WMO as part of the Meteorological Technology World Expo 2018.

Under the skeptic eye of the Royal Belgian Meteorological Institute, two units of the MeteoShield Professional were paired against two fan-ventilated atmospheric air temperature measurement systems used as the ultimate atmospheric air temperature references.

The results should have been predictable

Until the introduction of the helical (spiral or twister type) radiation shield by BARANI DESIGN Technologies, the results of radiation shield testing were mostly predictable. Fan-ventilated (fan-aspirated) shields that use an electric fan to drive air around a temperature sensor typically surpassed the accuracy of naturally ventilated multi-plate shields or Stevenson screens by 0.5°C or even by up to 3°C. Some of the most reputable air temperature sensor companies and their customers placed $300-$1500 precision sensors into expensive poorly performing shields only to end up with mediocre accuracy for a large financial investment. Affordable Davis Vantage Pro weather stations were many times able to surpass the accuracy and reliability of professional weather stations at 1/10th the cost. This was the status quo.


While many Met offices still cling to the old style Stevenson screen shelters for their reference measurements, a new era of precision atmospheric measurement may be upon us. While Stevenson created his shelter to perfection with the technologies at hand, new technologies of the 21st century allowed Jan Barani, educated at Rensselaer Polytechnic Institute (RPI) in aeronautical engineering, to create something not only more precise but arguably beautiful. Fan ventilation upgrades to the Stevenson screen design kept pace with modern fan-ventilated solar shields and screens until the introduction of the helical radiation shield design by BARANI DESIGN Technologies.

MeteoShield Pro - the new standard of atmospheric temperature measurement

Quoting the results of the Royal Belgian Meteorological Institute study, the standard deviation error of the patented helical shield design of MeteoShield Professional is 1/2 of their fan-ventilated shield which in layman’s terms means the helical MeteoShield Pro is twice as accurate. Whats more, the standard deviation of the MeteoShield Pro is 18% lower than their fan-aspirated Stevenson screen. Once again in layman’s terms we can say that the helical MeteoShield Pro is 18% more accurate than a fan aspirated Stevenson screen. If that was not enough, the helical MeteoShield’s precision in rainy conditions is almost twice as good as that of the fan-aspirated Stevenson screen reference and almost four times better than the RMI fan-ventilated shield.

Stable platform for climatological measurement

Climatology has a special set of requirements for monitoring global warming. Temperature minimums and maximums are not the most relevant values, actually they are only good for publicity. Average yearly temperatures are also only part of the picture. A detailed statistical analysis encompassing such terms as Standard Deviation, Skewness, Kurtosis, 1st Quartile, Median and 3rd Quartile in addition to the Minimums and Maximums need to be considered together. Effects of rain and snow, snow on the ground and the effects of ground color and ground type around the radiation shield or Stevenson screen are also important to consider. Taking all these variables and statistical terms into consideration, “MeteoShield Professional is really the only measurement platform that comes even close to fulfilling all the requirements. It is not perfect, but comes closest to finally being able quantify with confidence, the very slow (0.7°C per 100 years) climatic changes, which up till now, were stuck in measurement noise.

Is Barani better than Stevenson?

  • “The Barani's shelters have shown excellent results with a very limited heating under strong radiation. The mean overheating is as low as 0.2°C for medium global solar radiation and low wind speed (<1m/s). It is unclear why the overheating is lower for higher global solar radiation.”

  • “Despite the fact that the Barani shelters are not arti cially ventilated, their performances are better than our arti cially ventilated compact shelter.”

Quoted from the Intercomparison of Shelters in the RMI AWS Network, Luis Gonzaalez Sotelino, Nicolas De Coster, Peter Beirinckx, Pieter Peeters, Royal Meteorological Institute of Belgium, 3 avenue Circulaire 1180 Uccle, Belgium



What to look for in a HVAC outdoor air temperature sensor


Outdoor air temperature sensors (OAT) should possess the following qualities:

  • Robustness - radiation shield mount should ideally be made of corrosion resistant metal for strength and longevity and white in color to prevent overheating of the OAT sensor on sunny days.
  • Easy mounting - sensor and radiation shield mount should permit easy pole mounting and wall mounting. The mount should position the OAT sensor at least 8 inches (20 cm) from the mounting surface or wall.
  • High-quality radiation shield - quite a bit of money can be saved on temperature sensor cost by spending a little extra on a very good radiation shield. A high-quality radiation shield is especially important on hot sunny days since it determines the air temperature a sensor will measure. 

The trade-off between high-cost or a high-quality OAT sensor lies in the understanding that a temperature sensor will measure temperature only of air inside the radiation shield. In low-quality shields, even the most accurate and expensive sensors will measure unrealistically high air temperatures due to influences of wall heat radiating onto the shield or due to heating from direct or reflected sunlight. 

Overall system savings can be maximized by using a helical solar shield as written about in Meteorological Industry News and HVAC & Refrigeration Insider®.

Save time and money by installing your HVAC temperature sensor as close as possible

hvac outdoor heat EXCHANGER fan exhaust

hvac outdoor heat EXCHANGER fan exhaust

HVAC system's capacity is a function of outdoor air temperatures (OAT). Some estimates suggest an HVAC system's total capacity decreases by as much as 3% for every 4°F (~2°C) increase in outdoor air temperature. With focus on HVAC efficiencies on the rise and ever increasing electricity costs, it is important to monitor outdoor air temperature precisely. 

In the past, accurate OAT measurement has been cost prohibitive, but one small manufacturer with roots in upstate New York has come to the rescue with a patented design of a helical solar radiation shield for air temperature and humidity sensors.

Helical solar radiation shield for hvac outdoor air temperature (oat) sensors by barani design.

Helical solar radiation shield for hvac outdoor air temperature (oat) sensors by barani design.

A little-known company in the HVAC world, BARANI DESIGN Technologies, boasts years of experience in the meteorological sector. See "Helical radiation shield technology set to revolutionize air temperature measurement". Barani Design's experience in the aerospace industry nurtured at Rensellear Polytechnic Institute and Boeing, has led to many innovative designs. The helical radiation shield, while seemingly simple,  is proving to be the biggest innovation in air temperature measurement in decades.

The helical solar radiation shield achieves a combination of high accuracy and superb sensor protection unmatched in the market. It is able to measure air temperature accurately even in the proximity of sun-exposed exterior walls and other radiative heat sources which include HVAC rooftop systems. 

The device creates an internal vortex, which feeds fresh air to the OAT temperature sensor while providing 360° shielding from radiated heat and sun.   Improvements in accuracy can reach up to 8 °F on sunny days. Save time and money by installing your temperature sensor as close as possible, even if that means installing it on a sun-exposed wall. 

Please contact BARANI DESIGN Technologies s.r.o. worldwide and or allMeteo in the USA & CANADA for distributor pricing and more information:

BARANI DESIGN Technologies s.r.o.
Klincova 35
Bratislava, 82108 SLOVAKIA
TEL : +421 907 076 370

allMETEO (managed by COMPTUS, a BARANI DESIGN distributor)
202 Tamarack Road
Thornton, NH 03285, USA
TEL : +1 (603) 726-7500