Insider’s guide to UV lights and COVID-19

HVAC and UV lights

At Baker Plumbing, we are always trying to find the best and most effective approaches to solve the problems presented to us by our clients. Today we were asked to address the problem of bacteria within an HVAC system. As a professional HVAC contractor in Calgary, we immediately suggested the use of a UV light source inserted directly into the supply air of the HVAC system. You can watch a quick 1 minute video of it here :

BAKER and UV light install

UV light sources have long been used by the medical profession as a solution to eliminating infectious diseases and their sources. Learn more about UV below> NYC and UV Lights

Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency of approximately 30 PHz) to 400 nm (750 THz), shorter than that of visible light but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lampstanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms, it can cause chemical reactions and causes many substances to glow or fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules.

Short-wave ultraviolet light damages DNA and sterilizes surfaces with which it comes into contact. For humans, suntan and sunburn are familiar effects of exposure of the skin to UV light, along with an increased risk of skin cancer. The amount of UV light produced by the Sun means that the Earth would not be able to sustain life on dry land if most of that light were not filtered out by the atmosphere.[1] More energetic, shorter-wavelength “extreme” UV below 121 nm ionizes air so strongly that it is absorbed before it reaches the ground.[2] However, ultraviolet light (specifically, UVB) is also responsible for the formation of vitamin D in most land vertebrates, including humans.[3] The UV spectrum thus has effects both beneficial and harmful to life.

The lower wavelength limit of human vision is conventionally taken as 400 nm, so ultraviolet rays are invisible to humans, although some people can perceive light at slightly shorter wavelengths than this. Insects, birds, and some mammals can see near-UV

Sanitary compliance[edit]

A person wearing full protective gear, glowing in ultraviolet light

After a training exercise involving fake body fluids, a healthcare worker’s personal protective equipment is checked with ultraviolet light to find invisible drops of fluids. These fluids could contain deadly viruses or other contamination.

Ultraviolet light helps detect organic material deposits that remain on surfaces where periodic cleaning and sanitizing may have failed. It is used in the hotel industry, manufacturing, and other industries where levels of cleanliness or contamination are inspected.[83][84][85][86]

Perennial news features for many television news organizations involve an investigative reporter using a similar device to reveal unsanitary conditions in hotels, public toilets, hand rails, and such.[87][88]


Sterilization and disinfection[edit]

A low-pressure mercury vapor discharge tube floods the inside of a hood with shortwave UV light when not in use, sterilizing microbiological contaminants from irradiated surfaces.

Ultraviolet lamps are used to sterilize workspaces and tools used in biology laboratories and medical facilities. Commercially available low-pressure mercury-vapor lamps emit about 86% of their radiation at 254 nanometers (nm), with 265 nm being the peak germicidal effectiveness curve. UV at these germicidal wavelengths damage a microorganism’s DNA/RNA so that it cannot reproduce, making it harmless, (even though the organism may not be killed).[97] Since microorganisms can be shielded from ultraviolet rays in small cracks and other shaded areas, these lamps are used only as a supplement to other sterilization techniques.

UV-C LEDs are relatively new to the commercial market and are gaining in popularity.[failed verification][98] Due to their monochromatic nature (± 5 nm)[failed verification] these LEDs can target a specific wavelength needed for disinfection. This is especially important knowing that pathogens vary in their sensitivity to specific UV wavelengths. LEDs are mercury free, instant on/off, and have unlimited cycling throughout the day.[99]

Disinfection using UV radiation is commonly used in wastewater treatment applications and is finding an increased usage in municipal drinking water treatment. Many bottlers of spring water use UV disinfection equipment to sterilize their water. Solar water disinfection[100] has been researched for cheaply treating contaminated water using natural sunlight. The UV-A irradiation and increased water temperature kill organisms in the water.

Ultraviolet radiation is used in several food processes to kill unwanted microorganisms. UV can be used to pasteurize fruit juices by flowing the juice over a high-intensity ultraviolet source.[101] The effectiveness of such a process depends on the UV absorbance of the juice.

Pulsed light (PL) is a technique of killing microorganisms on surfaces using pulses of an intense broad spectrum, rich in UV-C between 200 and 280 nm. Pulsed light works with xenon flash lamps that can produce flashes several times per second. Disinfection robots use pulsed UV[102]



ECM Motors, The Good, The Bad and The Ugly

ECM motors are very popular amongst the HVAC sales force these days and while they certainly have some impressive features, be sure you understand what your getting into.


  • ECM motors are incredibly efficient in their use of energy, top rated with no doubt.
  • ECM motors are very quiet and frankly are almost silent in their operations.


  • While top rated in energy usage, the margins between first and second are slim.
  • PSC motors have come along way and are significantly cheaper component of the HVAC system


  • ECM motors are incredibly expensive to replace, as much as $1600 in some circimstances.


ECM motor swap