Comprehensive services in areas of testing, inspection, certification and training.

Hydrogen in gas appliances: a revolution in energy and the environment

In the Thermal and Environmental Laboratory we are part of the fascinating future of energy, specifically in the issue of hydrogen combustion in gas appliances. We approached our experienced colleague Milan Holomek, who has been leading a team testing this technology for several years.

Join us in discovering the future of hydrogen combustion in gas appliances in a report we have prepared together with the Guild of Heating and Plumbing Engineers, of which we are a member, and in whose current publication you will find the full interview, including seminars and news from the TIC sector, or from the world of testing, inspection and certification.

Interview "about hydrogen"

Hydrogen is gaining more attention as one of the interesting solutions for a more sustainable and energy future. Milan Holomek, Head of the Laboratory of Thermal and Environmental Equipment at the Engineering Test Institute in Brno, has been actively involved in the use of hydrogen in the energy sector for several years and will help us explore its potential for environmental and economic efficiency.

How long have you been involved in this innovative technology and what do you see as its greatest importance?

We have been working on the topic in our lab for over three years, and overall, adding hydrogen to the mixture for combustion in gas appliances has the potential to make a significant contribution to a more sustainable and environmentally friendly future for the energy sector, and also has the potential to help reduce dependence on fossil fuels.

Why are we even talking about hydrogen?

As part of the European Green Deal, the European Union has committed to start "greening" natural gas (G20) by adding hydrogen in the coming years. This is to be followed by a switch to hydrogen only. By greening, it is meant that natural gas, as a fossil fuel, will be replaced by hydrogen produced exclusively from renewable sources - e.g. from waste electricity from photovoltaic or wind power plants.

Are there any other benefits of burning a gas/hydrogen mixture besides the environmental aspect?

Adding hydrogen to the gas mixture can increase the energy efficiency of combustion. Hydrogen has a higher flammability than other gases, which means it can be used more efficiently and achieve more energy release with lower emissions. The benefits therefore include in particular a reduction in CO2, CO and NOx emissions compared to concentrated natural gas.

Are appliance manufacturers reacting to this?

Manufacturers are slowly starting to prepare for this transition. And we are also ready and doing testing for the manufacturers. Currently, the first major milestone being considered is a 20% hydrogen concentration in natural gas. This level is based on the fact that most products that have been designed to burn concentrated natural gas can tolerate concentrations of up to 20% hydrogen very well, even without the need for further design modifications to the appliances.

Do you test the adaptability of gas appliances to hydrogen admixture in your laboratory?

Yes, our gas appliance testing laboratory offers testing and certification of gas appliances burning natural gas with hydrogen admixture in addition to standard gases and gas mixtures defined by gas categories according to EN 437. Optionally, we can prepare other mixtures with hydrogen content in natural gas in addition to the 20% mixture. In the case of boilers, we offer measurements up to 2 MW. The principle is that we offer verification of the product design to ensure that it is fully adaptable to combust natural gas with up to 20% hydrogen in the mixture, without additional modifications to the appliance. Of course, we are also available for other specific requirements for testing and product design.

What specifically are you testing?

During the tests, we check the influence of the power input (due to lower calorific value), we test the ignition, flame propagation and stability (there should be no pulsation, backfiring, flame flight in both hot and cold conditions). We test safety conditions (blocking of flue gas exhaust and combustion air intake), we check safety times (for ignition and extinguishment), we make a special test of the resistance of the burner structure due to deliberate ignition and flame burning on the burner nozzle, we measure emissions (CO2, O2, CO and NOx), etc.

What is the output of your tests?

Testing reports are always the basis, which can be followed by other output documents such as assessment reports, final reports and possibly certificates or attestations.

As the legislative background is still under development, the current certification is more commercial. By certifying its products, the manufacturer thus declares that it is engaged in this modern trend and is thinking about the future needs of the market and the requirements of its customers. Our certification is based on specific tests and findings which provide evidence of a certain degree of guarantee of trouble-free behaviour of the products certified in this way.   

However, users of the appliances must not forget about regular service inspections. The certificate does not guarantee safety throughout the lifetime of the product.

Do you monitor other innovations in the field of thermal technology that will affect household energy in the future?

We are following many development paths. In our labs we also conduct non-accredited tests as part of some manufacturers' development tests, but for obvious reasons I cannot disclose these. There is a continuing boom in heat pumps, with efficiency improvements, reduced noise emissions and new refrigerants (after R32, it's now R290, more commonly known as propane). The drive to produce equipment that will reduce its environmental impact beyond its useful life continues. The trend towards local pellet or wood-fired sources continues, especially stoves, fireplaces and in some regions, cookstoves. There is also great interest in biomass boilers, which, thanks to the renewable status of biomass, fit very well into the energy mix of heating and hot water sources.

What else can you offer thermal technology manufacturers?

We offer comprehensiveness - we can test the product for electrical safety, noise emissions, pressure safety and performance. Manufacturers don't have to take their products to multiple locations, they can find a complete service with us. Our experts will carefully guide them through the entire product certification process.

The interview was published in a publication of the Guild of Heating Engineers and Plumbers. Read more at


Subscribe to our newsletter

News from the world of testing, inspection and certification