Choosing the Right UV Lamps for a UV System

UV lamps are the beating heart of the UV system, which provides the critical UV radiation that is capable of effectively inactivating harmful microorganisms. This means that choosing the right UV lamps for your disinfection system could determine the success of your disinfection process. 

Understanding UV lamps and their correlation to the germicidal wavelength spectrum will provide a great foundation for understanding the key principles of UV disinfection. With this knowledge you will be better suited to choose the right UV lamps for your next UV system.

In this overview you can expect to learn more about the germicidal spectrum used for UV disinfection, the different types of UV lamps, and an in-depth comparison of the UV lamp types.

The germicidal wavelength spectrum used for UV disinfection

The germicidal spectrum refers to a specific range of ultraviolet light wavelengths that possess the capability to inactivate harmful microorganisms such as bacteria, viruses, and protozoa. This spectrum most commonly spans within the UV-C range of 200-280 nm, with a peak germicidal wavelength around 254 nm. This range is highly effective in disrupting the DNA and RNA of harmful microorganisms, which results in the desired effect of inactivating the targeted harmful microorganisms.

Due to this, UV lamps that operate close to the 254 nm wavelength are utilized in disinfection processes all over the world, as this is scientifically proven to be the most efficient wavelength. However, there are factors that does not always make these types of lamps the best choice.

Overview of UV lamp types and efficiency

In the UV disinfection industry, UV systems primarily utilize two types of lamps, low-pressure and medium-pressure UV lamps.

UV lamp efficiency concerns the conversion of electrical energy into effective UV light.

While low-pressure lamps emit UV light at a wavelength of 254 near the peak of germicidal effectiveness, medium-pressure lamps function on a broader spectrum of UV wavelengths, as well as operating at higher temperatures.

Low-pressure lamps excel in efficiency, converting up to 40% of their input energy into usable UV-C output. This makes low-pressure lamps a cost-effective choice for continuous operation, as they convert a higher percentage of electrical input into germicidal UV light.

Medium-pressure lamps on the other hand are generally less efficient and convert about 10% of their input energy into UV-C output. However, despite the lower energy conversion, they can still be more effective in certain applications due to a higher energy output.

Key differences of low-pressure and medium-pressure UV lamps

To enhance the understanding of UV lamps and how they vary from each other, let’s delve into the key differences between the two lamp types.

While low-pressure lamps are often preferred in continuous, energy-efficient operations, medium-pressure lamps may be favored in applications requiring a higher intensity and possibly a broader germicidal range. The broader germicidal range means that medium-pressure lamps become particularly relevant for applications that deal with more resilient microorganisms such as protozoan cysts (Cryptosporidium and Giardia for instance).

Additionally, medium-pressure UV systems are available in a more compact design, that requires less space which means they can be integrated into complex environments with limited space such as wellboats.

Low-pressure lamps are also found to generally have lower maintenance requirements due to their longer lamp lifetime, which means they need less frequent servicing and replacement.

The UV lamps used in ULTRAAQUA UV systems have the following lamp lifetimes:

ULTRATHERM™ Low-Pressure High Output (LPHO) UV Lamps: 16.000 Hours

ULTRATHERM™ Medium-Pressure High Intensity (MPHI) UV Lamps: 9.000 Hours

Choosing UV lamps for the specific UV disinfection challenge

First and foremost, choosing the right UV lamps for the specific UV disinfection challenge includes an in-depth understanding of the specific requirements of the challenge. Additionally, it is beneficial to have a detailed understanding of exactly how uv systems work. Whether to choose low-pressure or medium-pressure lamps comes down to several factors, which include the following:

  • The application
  • Disinfection requirements
  • Water quality
  • Energy considerations
  • Desired level of pathogen inactivation

The main properties for a direct comparison can be found in the table below:

Low Pressure UV LampsMedium Pressure UV Lamps
WavelengthPrimarily at 254 nm.Emit a broader spectrum of UV wavelengths.
EfficiencyHigh efficiency, with up to 40% of electrical input converted to UV-C.Lower efficiency, typically converting up to 10% of input energy to UV-C.
ApplicationsSuited for applications where continuous, energy-efficient operation is needed.Better for applications requiring high-intensity UV light and a broader germicidal range.
Lamp LifespanLonger lifespan – Up to 16,000 hours.Shorter lifespan compared to low-pressure lamps – Up to 9.000 hours.
Energy ConsumptionLower energy consumption, more energy-efficient.Higher energy consumption.
Operational CostLower operational costs due to higher energy efficiency and longer lifespan.Higher operational costs due to lower efficiency and shorter lifespan.
IntensityLower intensity of UV light.Higher intensity of UV light.
Microorganism InactivationEffective against a broad range of microorganisms but may be less effective against certain resistant strains.Effective against more resistant microorganisms, including some protozoa and algae.
MaintenanceLower maintenance requirements.Requires more frequent replacements and servicing.
Environmental ImpactSmaller carbon footprint due to energy efficiency.Higher carbon footprint due to less energy efficiency.

If you are still in doubt about what the right choice is for your project, you are always welcome to get in touch with us.

ULTRATHERM™ Low-pressure UV lamps

The ULTRATHERM™ UV lamps utilized in ULTRAAQUA UV systems are based on 20 years of experience and extensive research, being continuously improved to reach optimized energy efficiency and durability. The research process has contributed to achieving the highest ever measured energy efficiency for a 3rd party validated UV system (based on the ÖNORM M 5873-1 standard).

The lamps provide 16.000 hours of guaranteed lamp lifetime with an extended temperature range from 2°C to 40°C, allowing UV systems to operate with stable efficiency worldwide.

The ULTRATHERM™ lamps from ULTRAAQUA incorporate the latest low-pressure Amalgam UV lamp technology, which makes them optimized for energy efficiency and robustness.

This ultimately makes the lamps able to provide optimized operating costs, providing minimum footprint and reduced electricity consumption.

If you are interested in hearing more about how we can help with UV disinfection, feel free to reach out to us anytime by contacting our sales engineers at – or by using the contact formula below.