[HN Gopher] Stossluften: Shock Ventilation
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Stossluften: Shock Ventilation
Author : sirobg
Score : 89 points
Date : 2023-12-30 09:10 UTC (13 hours ago)
(HTM) web link (www.thelocal.de)
(TXT) w3m dump (www.thelocal.de)
| timrichard wrote:
| I've started doing this in my home office after buying a CO2
| monitor. It's worked out pretty well. I don't trade much room
| temperature at all to get back close to 400PPM.
| Freak_NL wrote:
| Website doesn't seem to work. I get a header, a footer, but no
| content.
| fabian2k wrote:
| uBlock Origin blocks the entire article. The article also seems
| to be sponsored content, though I'm not sure what for exactly.
| The whole page seems a bit fishy and/or slightly broken.
| sirobg wrote:
| OP here. Agreed, it's kind of weird but I'm not sure why.
|
| I'm not German so I googled the word after seeing it on
| Twitter.
|
| I checked a few articles and this one had the most exhaustive
| description imho. That's why I decided to post this link
| despite some cons.
| vidarh wrote:
| I had the same thing, but it worked when I opened it in an
| incognito window.
| rolandog wrote:
| It didn't work for me, but viewing it in the WayBack Machine
| [0] did.
|
| [0] https://web.archive.org/web/20231230110629/https://www.th
| elo...
| shmeeed wrote:
| Incognito windows are better for Stossluften. Noted!
| mrspuratic wrote:
| when you open it in a new window it lets all the content out ;)
| vidarh wrote:
| This is used in Norway as well (and I suspect many other places).
|
| The term uses the same structure "sjokklufting", which like the
| German means shock ventilation.
|
| A quick search in the Norwegian National Library dates the
| Norwegian use of this specific term pretty firmly to ~1974 or so.
|
| Interestingly _all_ the uses of the term in writing in Norwegian
| media in 1970 's seem to either be or echo the text in an ad from
| Jotul, one of the largest manufacturers of cast-iron fireplaces
| as a negative (making it too cold), while many later mentions are
| positive, though also with a tinge of "we're only doing this as a
| fallback because our ventilation isn't good enough" in quite a
| few articles.
|
| A somewhat more common Norwegian variant describing much the same
| is utlufting ("out-ventilation") or storutlufting ("big out-
| ventilation"), which is found in print at least back to the
| 1850's, and which tends to imply much the same, though perhaps
| with a less negative slant.
|
| At some point around the 1980's, the viewpoint seems to have
| changed from promoting this as a good thing to describing the
| need for it as evidence of poor ventilation systems.
|
| My mum would often do this, and I do it myself too, - open
| several windows at least a couple of times a day during winter to
| rapidly clear out stale air. The benefit vs. less ventilation all
| the time being that while you're cooling the air, it's short
| enough that _you_ don 't lose much heat, and neither does the
| building mass. It's overall much more pleasant when it's really
| cold outside than having a window open a crack on an ongoing
| basis.
| sirobg wrote:
| Thanks for sharing this Norwegian perspective!
|
| I'm french and I don't think there is a specific word to
| describe this.
|
| We commonly use the verb "aerer" which translates to "to
| ventilate". But when someone uses this term, I think it
| designates implicitly a short ventilation as described by this
| German word or your Norwegian one. At least that's what I
| noticed around me. I don't know of anybody keeping a window
| open all day long to ventilate when it's cold outside.
| lwn wrote:
| In the Netherlands it's called "luchten". It's similar to
| "aerer". Both translate to "To air out" in English.
| vidarh wrote:
| Interestingly, Norwegian has both "luft" (air)/"lufte" (to
| air) and "lukt"/"lukte" (smell, to smell), and it turns out
| they share the same proto-Germanic origin as Dutch
| "luchten" as well as the equivalent German terms, and
| English "to lift" and Norwegian "a lofte", all centering
| around air with different angles.
| unhammer wrote:
| And in Bergen you can use "lukt" to mean both, "hoyt opp
| i lukten", maybe the Hanseatic influence?
|
| (My kid uses "luft" to mean both, "lufte ekkelt".)
| vidarh wrote:
| Germanic languages are very well suited to these kinds of
| compound words because you can pretty much keep adding words
| - hence the many jokes about ridiculously long German ones -
| where in many other languages if you want to add precision
| you use a phrase instead, or rely on context...
|
| You can do that in Norwegian too, but we tend to be a _bit_
| more shy about it than the Germans...
| snowpid wrote:
| I like to find language nerds on HN :)
| vidarh wrote:
| It's a subject well suited for obsessive pedants ;)
| spinningarrow wrote:
| A lot of newer (last 15 years or so) apartments in Oslo have a
| mixture of 'natural' ventilation through vents that let in cold
| air and mechanical ventilation in wet rooms, and even newer
| builds are starting to use 'balanced' ventilation that heats up
| cold outside air using heat from air that is being blown out
| https://www.byggmakker.no/rad-og-guider/kjokken-og-bad/vet-d...
| vidarh wrote:
| Yeah, it's obviously a lot more energy-efficient to have
| proper ventilation.
|
| (Then again, having recently flown back from Norway to the UK
| one of the things that strikes me every winter is how
| _floodlit_ Norway looks from the air at night compared to the
| UK despite far lower population density - Norway is still
| riding high on the past low energy prices...)
| zh3 wrote:
| Yes, heated pavements outside the shops, wind turbines on
| the hills, hydro, gravel roads and the sovereign wealth
| fund saving the money from oil for the future (check out
| https://www.nbim.no/, it's about 10Nok to the dollar).
| BrandiATMuhkuh wrote:
| My landlord here in Austria put that in the flat "manual". It's
| the main technique to avoid high humidity in Winter. Because high
| humidity means you won't feel warm and it fosters mold.
| sirobg wrote:
| OP here. I even read it was sometimes required in the lease
| terms!
|
| https://allaboutberlin.com/glossary/Sto%C3%9Fl%C3%BCften
| fabian2k wrote:
| In Germany as a tenant it is usually your duty to ventilate
| properly. If you do not do that and this results in mold you
| as a tenant are responsible, not the landlord. This is of
| course much more complex in practice, as mold is often not
| caused by poor ventilation but by bad construction. So the
| blame can lie with the landlord, or the tenant or both
| depending on the specific case.
| groestl wrote:
| Can confirm (Austrian here)
| HL33tibCe7 wrote:
| Is this not a waste of energy?
| fabian2k wrote:
| Compared to what? Permanently venting air is a much bigger
| waste of energy.
|
| Most of the heat is in the walls, not the air anyway.
| theshrike79 wrote:
| 5 minutes of cool air entering the house isn't a huge amount,
| but it does bring in fresh air.
| orbital-decay wrote:
| Yes, to a certain degree it undermines the point of having good
| insulation (as in, _really_ good - when the thermal mass of the
| air starts to matter). Modern "nearly zero-heating" houses
| have long heat exchangers in the vents to avoid the waste.
| ikekkdcjkfke wrote:
| Trade off
| the_mitsuhiko wrote:
| Since forced-air heating is uncommon in Europe the impact is
| not that high. The radiators or under floor heating stays warm
| and will re-heat the air very quickly.
| zeitgeistcowboy wrote:
| No, not necessarily. If it lowers the humidity, then it can
| take less energy to heat the house after venting. So it can
| actually save energy.
| Daniel_sk wrote:
| Minimal. Most houses have thick walls and there is a lot of
| accumulated energy - the air reheats quickly after closing the
| windows.
| Phelinofist wrote:
| I'm German and this was drilled into my head since I was a child.
| My dad insisted on doing this. Every landlord I had so far
| required doing this to avoid mold. I do it before I go to sleep,
| because some fresher/cooler air also helps me sleep better. It is
| also done in offices and schools.
| ano-ther wrote:
| Seems to be the best way to get rid of stale air (while
| conserving energy) in a country that prides itself of its
| tightly sealed windows.
|
| > Asked by the tabloid BILD-Zeitung what feelings Germany
| awakes in her, Angela Merkel once famously replied, 'I think of
| well-sealed windows! No other country can make such well-sealed
| and nice windows [dichte und schone Fenster].'
|
| https://nybooks.com/articles/2013/08/15/new-german-question/
| konschubert wrote:
| No.
|
| The best way is ventilation through heat exchangers.
| sjfjsjdjwvwvc wrote:
| Wrong. The best way is the method described in the OP post.
| throwaway8877 wrote:
| In comparison to what and how?
|
| It really doesn't matter how fast you replace the air. If you
| let in the cold air then you need to warm it up.
|
| What you actually do is a compromise between energy
| conservation and properly ventilated room as for the morning
| the room will be filled with high concentration of CO2 and
| humidity (from your breathing and sweating) and you more than
| often end up with bad sleep and headache.
|
| Constant proper mechanical ventilation is the key for better
| sleep and health when windows are goods as German windows
| (some other European countries make good windows too).
| _Microft wrote:
| > It really doesn't matter how fast you replace the air. If
| you let in the cold air then you need to warm it up.
|
| Ventilating quickly is preferable to ventilating slowly.
| Heat transfer through materials is comparatively slow. That
| means that exchanging the air in an instant retains the
| heat in the walls, furniture,... exchanging the air slowly
| allows heat from materials to ,,leak out" as well.
| euroderf wrote:
| AFAIK it's more typically known simply as "Luft" ("air). And the
| idea is great. Flush the room of aerial crud as quickly as
| possible so that objects in the room retain their heat.
| sgbeal wrote:
| > AFAIK it's more typically known simply as "Luft"
|
| "Luften" is the common local term ("to air out").
| blensor wrote:
| Are you writing this on an English keyboard ;)
|
| I am pretty sure most modern browsers are able to display an
| u so you can write "Luften"
| sgbeal wrote:
| Indeed, i was on a US keyboard. The u has since been
| corrected. (Or it's been edited, but this client is still
| showing the typo. Perhaps i waited too long to edit it.)
| the_mitsuhiko wrote:
| I was just joking about this today. For years I have heard all
| kinds of dismissive attitude to this concept yet the last few
| months tech Twitter has been full of people buying really
| expensive CO2 meters, presumably because they were unaware of CO2
| in rooms?
|
| When you buy a Window here, or you rent a flat it usually comes
| with a manual that asks you to ventilate regularly and how.
|
| If you ventilate properly, a CO2 meter is entirely pointless. CO2
| levels are very predictable and you can also usually tell when
| the air quality drops through your senses.
| flemhans wrote:
| I can't feel 2000 PPM through my senses. But at 4000 it starts
| getting stuffy.
| the_mitsuhiko wrote:
| I really find this hard to believe. 2000 is already at the
| higher threshold of where people report bad air quality and
| drowsiness. In practical terms it doesn't matter much because
| if you are ventilating properly, your CO2 levels don't stay
| elevated for long and you really do not need to measure or
| observe.
| Zetobal wrote:
| 4000 is a badly ventilated bedroom and 5000 is the limit
| for sustained working. If you get nauseous at 2000 you are
| highly sensible.
| the_mitsuhiko wrote:
| We have a CO2 level at home, so I can validate my
| personal observations and those of others. But I don't
| even need to go to personal anecdotes, everything you can
| read on CO2 levels indicates that people notice.
| Zetobal wrote:
| Notice is highly different from getting nauseous.
| the_mitsuhiko wrote:
| Not sure where you are getting nausea from.
| Smaug123 wrote:
| > you can also usually tell when the air quality drops through
| your senses
|
| Only when you're paying attention. If I'm not paying attention,
| I end up in a sufficiently depressed state that I can't notice,
| which is _extremely_ self-perpetuating.
| the_mitsuhiko wrote:
| If you are ventilating regularly your CO2 levels are not
| raising to ridiculous levels in the first place. I'm pretty
| sure for most people the novelty of the CO2 measurement
| device wears of quickly.
| Franzeus wrote:
| Funny - Doing this exact thing while reading this post
| mxstbr wrote:
| This is the first German word I taught my (American) partner and
| it is, to this day, likely our most used German word. Such a core
| concept to our entire culture!
| wongarsu wrote:
| A big part of why this works so well in German homes is that they
| have a high thermal mass. Even single family homes are built with
| concrete floors and plastered over brick walls (brick as in
| square building block, I think the currently popular form is
| expanded concrete?).
|
| In these buildings, you can replace all air with outside air at
| once, and once you close the windows the thermal mass of the
| building will quickly heat it up again.
|
| New buildings tend to move away from it though, instead using
| automatic fans for ventilation
| froh wrote:
| the reason being that with ventilation, you can do a heat
| exchange between incoming and outgoing air.
|
| the structure and thermal mass is similar in new buildings.
| throwaway8877 wrote:
| Mechanical mentilation (with fans) is considerably better in
| many ways.
|
| It allows heat recovery - less heating (or cooling) energy is
| wasted by proper ventilation.
|
| Ventilation is constant - there is no buildup of CO2, moisture
| or harmful particles like VOC or viruses.
|
| There is no need for discomfort caused by the shock ventilation
| when ventilation is properly dimensioned (enough for people in
| the room).
| sjfjsjdjwvwvc wrote:
| Is mechanical ventilation referring to air conditioning?
|
| In that case I would disagree, it's a magnitudes bigger waste
| of energy and resources and causes illness (at least for me).
| ricardobeat wrote:
| No. It usually takes the form of extractors in the most
| humid locations of the house (kitchen, bathroom, laundry)
| that are connected to a central unit that vents air to the
| outside. Fresh air comes in through ventilation grills
| around the house, normally located above windows by means
| of the resulting pressure. No air conditioning is involved,
| or recirculating, though more modern (and much more
| expensive) units have heat recovery systems and air filters
| that will also bring fresh air back in.
| ctroein89 wrote:
| Mechanical ventilation refers to just using fans. The
| comment you're replying to is suggesting that heat recovery
| ventilators (HRV) be used to transfer heat from the warm
| exhausted to the incoming outside air via a heat (or cools
| incoming outside air in hot climates). It reduces the need
| for heating or cooling while still getting fresh air into
| the building.
| sbierwagen wrote:
| >brick as in square building block
|
| Concrete masonry unit, "cinderblock" in North America.
| https://en.wikipedia.org/wiki/Concrete_block
| upofadown wrote:
| One way or the other you have to heat up the air again. The
| main reason this works is because air has very low thermal
| mass. Something like a thousand times less than typical solid
| materials. Even a small amount of solid mass is not going to
| cool down that much in such a short period of time.
| genman wrote:
| I think there is one single factor why it is done and it is
| more energy efficient in comparison to keeping windows
| slightly open all the time for constant ventilation.
|
| Rooms are mainly heated by water radiators in Germany. These
| radiators are most likely under windows to compensate for the
| radiated cold and draft from the windows that may create
| discomfort. As the heat moves up then it will create (mainly)
| closed circulation in the room when the windows are closed.
|
| Now when the windows are open then the heat from the
| radiators will instead escape from the windows. On top of
| this the radiators are most likely locally regulated (with
| thermal valves) and will heat up because of the cold air from
| the outside while increasing the energy loss even more.
|
| This is the main reason why the heating must be closed during
| the shock ventilation and why it is less energy efficient to
| keep the windows slightly open for constant ventilation.
|
| This is of course a compromise between good air quality and
| energy efficiency and the correct answer is to build a proper
| mechanical ventilation with an heat exchange.
| jeffrallen wrote:
| Shock ventilation is a habit of Swiss housewives which is
| diametrically opposed to the new "Minergie" standard for green
| homes, which provides for air exchange via a super expensive heat
| exchanger system which extracts heat from stale air before
| sending it out.
|
| Of course everyone who lives in Minergie homes opens the windows
| each morning while hanging out the duvets, and/or complains that
| the enormous windows are too big to open, or don't open at all.
|
| It's like all the Minergie engineers were so busy at work they
| didn't notice what their wives were doing at home. (I assume the
| original engineering for these hear exchangers was in the 70's
| when that gendered statement was not controversial!)
| palemoonale wrote:
| Not possible in the US with all its closed-up office and hotel
| rooms.
| moron4hire wrote:
| Also, not really necessary. It's more of an Old Wives Tale than
| an effective practice.
|
| The only place I have trouble with mold is in the bathroom, and
| that's because so many homes built before the 80s were built
| without ventilation fans in the bathroom. The places I've lived
| with proper ventilation have not had mold problems.
| dzhiurgis wrote:
| While it's true germans are plagued with all sort of holistic
| medicine and homeopathy mind virus, this one is true. With
| covid wave there was explosion of co2 meters and tons of
| people realised they live in stuffy air all the time.
|
| What's depressing is that neither rental rules do not require
| HRVs yo be installed nor little public places have started to
| upgrade.
| layer8 wrote:
| > Let's start with the translation. Literally, Stoss means
| "shock, impact or thrust" and luften means "ventilating."
| Stossluften therefore translates to "shock ventilation."
|
| I'd say the connotation is more of a quick blowing out, ejection
| or (im)pulse, not a shock. Compare also "ausstossen" and
| "Stossatmung". The main feature is the short duration.
| neonate wrote:
| https://web.archive.org/web/20231230110629/https://www.thelo...
|
| https://archive.ph/KW0ZC
| drsim wrote:
| My Velux roof windows do this automatically for me every day.
| Works great as they won't open if it is raining or too cold.
| Sucks that the radiators don't turn off at the same time, so some
| wasted energy there.
| Empact wrote:
| Another automatic option for achieving these air quality goals
| is to use an HRV/ERV for continuous fresh air in the house, as
| they do in Passive House construction. Doing heat exchange
| between the outgoing and incoming air makes it a very energy
| efficient system.
| https://en.wikipedia.org/wiki/Heat_recovery_ventilation
| https://www.zehnderamerica.com/heat-recovery-ventilator/
| karolist wrote:
| Do you have any control of the radiators? I have Velux GGU
| windows too and plan on doing Home Assistant integration for
| precisely the reasons you mention plus some automatic shading
| based on sun position or light sensors. For this I understand
| you need a KLF200 interface [1] and of course HA integration
| [2], then the integration possibilities are pretty much
| endless.
|
| 1. https://www.baubay.de/home-interface-velux-klf-200.html
|
| 2. https://community.home-assistant.io/t/velux-kfl200-ha-
| config...
| throwaway8877 wrote:
| It helps when you don't have actual appropriate mechanical
| ventilation as you should have with modern windows and
| insulation.
|
| A large part of the European buildings still don't have proper
| ventilation.
| mhb wrote:
| European Windows Are Awesome
|
| https://news.ycombinator.com/item?id=38818803
| blub wrote:
| This "Stossluften" is just opening a couple of windows for
| several minutes to create a draft.
|
| There's a nice booklet about ventilation for regular Joes called
| "Richtiges Luften in Wohnungen" (Proper ventilation in
| apartments) published by the Fraunhofer IRB (i.e. information
| centre for inner spaces and construction).
|
| This booklet explains the role of material and air humidity, how
| ventilation became important as buildings became more airtight,
| how relative humidity works, etc.
|
| A key observation is that the main purpose of such intense
| ventilation is refreshing the air, i.e. removing unpleasant
| smells and CO2.
|
| Landlords, experts and courts of law have nevertheless settled on
| the idea that 2-3x intensive ventilations per day are necessary
| to avoid mould.
|
| The booklet claims that dehumidification is ideally achieved
| through "Spaltluften", which is keeping a window partly open for
| a _longer_ period of time: the cool outside air enters the room
| in small quantities which can be quickly heated, thereby drying
| said air and enabling it to absorb additional humidity. Due to
| the longer ventilation period, materials which absorb humidity
| such as drapes, carpets, wallpaper or plaster can release said
| humidity which shall be absorbed by the dry air and ultimately
| exchanged with outside air. The heater must stay permanently on
| so that the cool air can be heated.
|
| Some apartments have passive mechanical ventilation such as
| openings in the rubber seals of the windows or ventilation slots
| in the window frames which follow this principle.
| franczesko wrote:
| It's also due to the fact, that many German buildings are old and
| therefore carry poor ventilation parameters.
|
| Newer buildings probably don't need shock ventilation, as it's
| better by design.
| bill38 wrote:
| See also https://news.ycombinator.com/item?id=38819249
| alkonaut wrote:
| Sounds like building codes haven't forced old buildings to be
| retrofitted with decent ventilation. If that's not possible then
| it shouldn't be a school.
| kyledrake wrote:
| If anyone wants way too much information on doing continuous
| ventilation fans in your house to improve air quality:
|
| https://news.ycombinator.com/item?id=25139125
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(page generated 2023-12-30 23:01 UTC)