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efficiency_now:immediate_measures:technology:showerhead [2022/08/24 11:46] – [Protection with high-quality legionella filter] wfeistefficiency_now:immediate_measures:technology:showerhead [2022/08/24 11:58] (current) – [Protection with high-quality legionella filter] wfeist
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 ==== Protection with high-quality legionella filter ==== ==== Protection with high-quality legionella filter ====
  
-Now the latest filter technology can be used for protection against legionella exposure: using microfilters with opening cross-sections considerably less than 0.2 µm, it is possible to eliminate these microbes which are larger than 1 µm. These are available as so-called "terminal filters" i.e. filters directly in front of the shower head. The filtration effect has been confirmed by independent laboratory measurements. \\+{{ :efficiency_now:immediate_measures:technology:duschkopf_hygfilter.jpg?150|}}Now the latest filter technology can be used for protection against legionella exposure: using microfilters with opening cross-sections considerably less than 0.2 µm, it is possible to eliminate these microbes which are larger than 1 µm. These are available as so-called "terminal filters" i.e. filters directly in front of the shower head. The filtration effect has been confirmed by independent laboratory measurements. \\
 We tested one such shower head with regard to practical application:  We tested one such shower head with regard to practical application: 
   - The shower head comes with a built-in filter and in appearance is no different from a modern "ordinary" shower head.   - The shower head comes with a built-in filter and in appearance is no different from a modern "ordinary" shower head.
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   - Showering with this is no different from the previously used shower head: the shower feels 'full', shampoo can be washed out of the hair in a short time, the entire duration of the shower remained unchanged (as always, I needed approximately 3 minutes; such times are very different for each individual, this information has only been provided for reference). \\   - Showering with this is no different from the previously used shower head: the shower feels 'full', shampoo can be washed out of the hair in a short time, the entire duration of the shower remained unchanged (as always, I needed approximately 3 minutes; such times are very different for each individual, this information has only been provided for reference). \\
 Compared to frequently found shower heads with 12 l/min, water consumption can be reduced by around one half due to the lower flow rate((This applies for all the different required showering times provided that this time does not change with the other shower head; according to the available experience, this also shouldn't be the case.)). The energy saving for usable heat (that which is made available by the shower head) is thus also halved. However, because a quite large share of the energy demand for hot water consists of circulation and storage losses, the total energy consumption is reduced "only" in the range of 25 to 30 %.  Compared to frequently found shower heads with 12 l/min, water consumption can be reduced by around one half due to the lower flow rate((This applies for all the different required showering times provided that this time does not change with the other shower head; according to the available experience, this also shouldn't be the case.)). The energy saving for usable heat (that which is made available by the shower head) is thus also halved. However, because a quite large share of the energy demand for hot water consists of circulation and storage losses, the total energy consumption is reduced "only" in the range of 25 to 30 %. 
-In single family houses a very high level of safety can be assumed due to the terminal filter((The manufacturer provides proof for a retention factor of 10<sup>7</sup>. Extreme values for contamination in DHW systems with high exposure were less than 10<sup>6</sup> CFU/(100ml). Even with such maximum values the terminal filter ensures a reduction to less than 1 CFU/(100 ml). For comparison: values around 30 CFU/(100 ml) already exist in average cold water installations.)): under these circumstances, the risk is reduced even further also with storage and circulation temperatures of 45° provided by heat pumps ((We will add a basic information section about the risks and their assessment in due course, but here are some remarks on this already at this point:+In single family houses a very high level of safety can be assumed due to the terminal filter((The manufacturer provides proof for a retention factor of 10<sup>7</sup>. Extreme values for contamination in DHW systems with high exposure were less than 10<sup>6</sup> CFU/(100ml). Even with such maximum values the terminal filter ensures a reduction to less than 1 CFU/(100 ml). For comparison: values around 30 CFU/(100 ml) already exist in average cold water installations.)): under these circumstances, the risk is reduced even further also with storage and circulation temperatures of 45° provided by heat pumps((We will add a general information section about 'risks and their assessment' in due course, but here are some remarks on this already at this point:
   - Much as we would desire it, it is definitely **not possible to achieve "zero risk"** in many areas of our daily lives: e.g. even collisions between inattentive pedestrians can lead to serious injuries in the worst case.   - Much as we would desire it, it is definitely **not possible to achieve "zero risk"** in many areas of our daily lives: e.g. even collisions between inattentive pedestrians can lead to serious injuries in the worst case.
   - However, such "residual risks" are usually **extremely low.** For example, fatal accidents with bikes without the involvement of motor vehicles are less than 0.16 annually per 100.000 persons (133 persons in the year 2020 in Germany according to [destatis 2020]).   - However, such "residual risks" are usually **extremely low.** For example, fatal accidents with bikes without the involvement of motor vehicles are less than 0.16 annually per 100.000 persons (133 persons in the year 2020 in Germany according to [destatis 2020]).
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   - Other measures might possibly further reduce the risk slightly, but again, not to zero, unfortunately. Thus the consistent use of **bicycle helmets** would perhaps bring down the related standardised risk to 0.02 a<sup>-1</sup> and we would also endorse this in view of the low effort for this. The additional increase in hot water temperatures to above 60°C generally everywhere in the system (beyond the terminal filter) in contrast would achieve a barely measurable improvement because the residual risks that still exist in this area now come mainly from the standing heated cold water;  However, the effort here is huge because the heat losses are doubled. Likewise, with an additional increase in the air change rate (to 0.8 h-1, as often suggested), the radon concentrations would hardly be measurably reduced any further because according to the available measurement results with a correctly dimensioned heat recovery ventilation system, the values are already close to those of the outside air concentrations; in this example the respective effort would also be unreasonable (continuous operation of humidification systems would be necessary in winter).   - Other measures might possibly further reduce the risk slightly, but again, not to zero, unfortunately. Thus the consistent use of **bicycle helmets** would perhaps bring down the related standardised risk to 0.02 a<sup>-1</sup> and we would also endorse this in view of the low effort for this. The additional increase in hot water temperatures to above 60°C generally everywhere in the system (beyond the terminal filter) in contrast would achieve a barely measurable improvement because the residual risks that still exist in this area now come mainly from the standing heated cold water;  However, the effort here is huge because the heat losses are doubled. Likewise, with an additional increase in the air change rate (to 0.8 h-1, as often suggested), the radon concentrations would hardly be measurably reduced any further because according to the available measurement results with a correctly dimensioned heat recovery ventilation system, the values are already close to those of the outside air concentrations; in this example the respective effort would also be unreasonable (continuous operation of humidification systems would be necessary in winter).
   - In contrast, improved infection prevention measures for example have been proven to be able to minimise the COVID risk by a factor of 4 to below 11 a<sup>-1</sup> (wearing of masks). Or, pedestrian safety can be improved by a factor of 2 by means of speed regulation in inner cities. In these areas with a still high risk, the effort for further reductions is quite small.   - In contrast, improved infection prevention measures for example have been proven to be able to minimise the COVID risk by a factor of 4 to below 11 a<sup>-1</sup> (wearing of masks). Or, pedestrian safety can be improved by a factor of 2 by means of speed regulation in inner cities. In these areas with a still high risk, the effort for further reductions is quite small.
- ))+ )).
  
 The terminal filter inside the shower head is simply much more effective for preventing legionella exposure than permanent thermal disinfection. The terminal filter inside the shower head is simply much more effective for preventing legionella exposure than permanent thermal disinfection.
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 Water-saving shower heads are available on the market at the same prices as conventional ones. With the lack of information for most products, the only trouble is finding suitable shower heads which make a comfortable showering experience possible also with lower flow rates.  Water-saving shower heads are available on the market at the same prices as conventional ones. With the lack of information for most products, the only trouble is finding suitable shower heads which make a comfortable showering experience possible also with lower flow rates. 
-Extra filter costs of around 100 €/a may well be incurred for a terminal legionella filter. However, the saved energy costs alone are about 125 € each year, and in addition approximately 25 € are saved for potable water.  +Extra filter costs of around 100 €/a may well be incurred for a terminal legionella filter. However, the saved energy costs alone are about 125 € each year, and in addition approximately the same costs are saved for potable water.  
-What matters much more is the fact that such a solution allows operation of the hot water system with a commercially available hot water heat pump as well. According to our assessment, it would be reasonable to aim for a rapid switch to shower heads of the quality described here; this would reduce the number of illnesses in this connection as well as the energy consumption and thus also CO2 emissions. At the same time, the switch to heat pumps (largely renewable energy based systems) for domestic hot water will also be enabled in this way in the medium term.  +What matters much more is the fact that such a solution allows operation of the hot water system with a commercially available hot water heat pump as well. According to our assessment, it would be reasonable to aim for a rapid switch to shower heads of the quality described here; this would reduce the number of illnesses in this connection as well as the energy consumption and thus also CO<sub>2</sub> emissions. At the same time, the switch to heat pumps (largely renewable energy based systems) for domestic hot water will also be enabled in this way in the medium term.\\ \\   
-[[planning:building_services|Back to overview "Measures relating to building services technology"]] +[[planning:building_services|Back to overview "Measures relating to building services technology"]]\\  
-Or to the overview relating to the [[planning:thermal_protection|building envelope. ]]+Or to the overview relating to the [[planning:thermal_protection|building envelope. ]]\\ \\ 
  
 ===== References ===== ===== References =====
efficiency_now/immediate_measures/technology/showerhead.1661334394.txt.gz · Last modified: by wfeist