How bacteria and viruses can be controlled with the help of the HVAC unit
Besides the fact that they provide comfort, HVAC unites also help conserve a healthy indoor environment. There are numerous health dangers that can occur in a room where an HVAC system is not working properly. We all know that comfort and good health improve productivity, which is why it is very important for all companies to offer a quality indoor environment for their employees. Providing superior control over dangerous organisms like viruses, bacteria, and mold and dust mites is one of the most important advantages of a well-designed HVAC system. All building owners should make sure that they are kept under control, as these organisms may represent a hazard for air quality and health.
A 50% or lower level of humidity in the air is recommended by the US Environmental Protection Agency in order to improve IAQ. Consider the maximum amount of water that the air can hold, we can say that relative humidity is the percentage of water in the air.
Viral infections can be reduced through air humidity
Many viruses, included the Coronavirus, spread easier and faster through dry air, so this is why it is very important to set a proper relative humidity in the building you live in. Below you will find a couple of reasons why viral infections are common with cold and dry weather:
- When there is low humidity in the air, airborne particles stay longer in the air
- Viral infections can settle in much easier if the mucous membranes that protect the human respiratory system are dried up, which usually happens in low humidity
- Cold air has a lower relative humidity level, which can contribute to all the aspects mentioned above, even though it does not affect the spread of viruses
- Viruses spread much easier in closed spaces, and this is where we all spend our time during the cold weather
The way through which air humidity affects flu virus infections was studied by the Centers for Disease Control and Prevention. Viruses are spread much easier during the winter season since the space heating system can make indoor air drier than outdoor air. Besides temperature control, all HVAC systems should be able to control the relative humidity in the air as well. Healthcare and retirement homes belong to a more sensitive class of buildings, so additional measures must be taken in these facilities.
The spread of viruses can be prevented with the help of an increased level of humidity in the room. Increased levels of humidity can also have negative effects on IAQ, so make sure you find the right balance.
Indoor air quality and health can be negatively affected by high humidity
Viral infections strive where dry air is present because it causes particles to stay airborne for longer. The growth of bacteria, mold, and dust mites is stimulated by humid air. Indoor air quality is really poor where these organisms are present. The recommended level of relative humidity in the air is not quite clear at the moment, but some experts believe that it should be less than 50%.
When relative humidity is lowered down to the recommended range, the chances for mold and dust mites to die off are increased considerably. Considering the fact that dead mold spores and dust mites can also trigger an allergic reaction, it is equally important to filter the air. Particles with a diameter of 0.3 microns are all captures with the help of a HEPA filter, which is why experts recommend it to clean the air in which you live in.
How to effectively control indoor air humidity
Exchanging humidity between the exhaust air and the outdoor air supply is possible with the help of an energy recovery ventilation system in combination with an enthalpy wheel. Humidity can be increased and decreased as needed with the help of an ERV system:
- The exhaust air can easily get rid of that moisture through the ERV system when the outdoor air supplied to the building is humid.
- Considering the fact that the ERV system recovers humidity from the exhaust air, the opposite applies when outdoor air is dry.
Besides the fact that they provide control over air moisture, space heating and air conditioning systems will also contribute to the thermal comfort of your family. Even though they consume a lot of energy, additional humidifiers and dehumidifiers can be used to increase control over the relative humidity. However, if the HVAC system cannot reach a proper humidity ranger on its own, experts recommend investing in an additional humidifier.
Other tips to consider
Selecting the correct size of an air conditioner should normally be done by a professional, as it depends not only on the number and size of the rooms but also on the size and orientation of the windows, exposure to solar radiation and other factors such as interior clearance.
For example, for a bedroom of 20 square meters, a 7000 BTU unit can be chosen. If the apartment is not isolated and the orientation is south, it is recommended to increase the capacity of the unit to 9000 BTU. It is advisable to position the indoor unit in such a way that the airflow crosses the surface of the outer wall, which is prone to the highest heat losses/inputs. Also, the route of the refrigerant linking the indoor unit to the outdoor unit must be as short as possible. Last but not least, the noise produced by the devices must be taken into account, the most efficient being able to operate at only 19 dB, which is equivalent to the noise of the leaves.