Academic Edi o s: Se gio Mon elpa e
and Camilla Lops
Recei ed: 27 Ma ch 2025
Re ised: 5 May 2025
Accep ed: 8 May 2025
Published: 13 May 2025
Ci a ion: Aguila -Ca asco, M.T.;
López-Lo illo, R.M.; Suá ez, R.;
León-Rod íguez, Á.L. Ven ila ion
S a egies o Ensu e The mal Com o
o Use s in School Buildings: A
C i ical Re iew. Appl. Sci. 2025,15,
5449. h ps://doi.o g/10.3390/
app15105449
Copy igh : © 2025 by he au ho s.
Licensee MDPI, Basel, Swi ze land.
This a icle is an open access a icle
dis ibu ed unde he e ms and
condi ions o he C ea i e Commons
A ibu ion (CC BY) license
(h ps://c ea i ecommons.o g/
licenses/by/4.0/).
Re iew
Ven ila ion S a egies o Ensu e The mal Com o o Use s
in School Buildings: A C i ical Re iew
Ma ía Te esa Aguila -Ca asco 1, Remedios Ma ía López-Lo illo 1, Ra ael Suá ez 2,*
and Ángel Luis León-Rod íguez 2
1Depa amen o de Cons ucciones A qui ec ónicas I, Escuela Técnica Supe io de A qui ec u a,
Uni e sidad de Se illa, A . de Reina Me cedes 2, 41012 Se ille, Spain; [email p o ec ed] (M.T.A.-C.);
[email p o ec ed] (R.M.L.-L.)
2Ins i u o Uni e si a io de A qui ec u a y Ciencias de la Cons ucción, Escuela Técnica Supe io
de A qui ec u a, Uni e sidad de Se illa, A . De Reina Me cedes 2, 41012 Se ille, Spain; [email p o ec ed]
*Co espondence: sua [email p o ec ed]
Abs ac : People spend mos o hei ime indoo s, whe e ai quali y is c ucial o heal h.
In his con ex , his s udy conduc s a c i ical e iew o en ila ion s a egies in schools
o ensu e ai quali y, as well as o gua an ee s uden s’ he mal com o . Based on a
bibliog aphical e iew, s a egies om p e ious s udies a e iden i ied and e alua ed in
o de o de e mine hei ad an ages. A e a de ailed sea ch, a o al o 19 a icles we e
selec ed, which p o ides a ho ough analysis o he en ila ion s a egies in school buildings
conside ing he mal com o . The iden i ied s a egies we e ca ego ized in o na u al,
mechanical, and hyb id ypes. The esul s e eal a p e alence o na u al en ila ion,
which accoun s o o e 50% o s a egies in all clima es. Mechanical en ila ion is less
common and is applicable o a ound 30% o cases. Hyb id s a egies, combining na u al
and mechanical en ila ion, a e he leas used and only appea in oceanic clima es, wi h
a usage a e o 20%. Mos s udies highligh he lack o ai condi ioning in many schools,
making adequa e he mal s ess managemen h ough en ila ion c ucial. The esul s
analyzed clea ly show a lack o s udies wi h op imal esul s whose en ila ion s a egies
can be eplica ed in o he simila educa ional buildings, ensu ing he mal com o and
ai quali y.
Keywo ds: en ila ion; he mal com o ; school; s a egy; indoo ai quali y
1. In oduc ion
In con empo a y li es yles, people spend mos o hei ime inside buildings, whe e
ac o s such as indoo ai quali y and he mal com o become essen ial o ensu ing hei
heal h, a undamen al pa o li e. Acco ding o he Wo ld Heal h O ganiza ion (WHO),
ai pollu ion is anked among he g ea es en i onmen al heal h isks [
1
], wi h p olonged
exposu e leading o se ious heal h p oblems in humans. Nume ous s udies ha e quan i ied
he isk o su e ing di e en diseases a ec ing he espi a o y [
2
], ca dio ascula [
3
],
immune [
4
], and neu ological sys ems [
5
]. This also inc eases he isk o indi iduals
de eloping ch onic diseases [
6
–
8
]. Ensu ing op imal indoo ai quali y is he e o e key o
mi iga ing hese heal h isks and p omo ing o e all well-being. On he o he hand, he
lack o he mal com o esul ing om o e hea ing and unde cooling inside buildings
also poses a se ious isk o heal h [
9
], causing se e e illnesses [
10
], impai ing cogni i e
pe o mance [
11
], and leading o a decline in dex e i y and manual execu ion capaci ies [
12
].
Appl. Sci. 2025,15, 5449 h ps://doi.o g/10.3390/app15105449
Appl. Sci. 2025,15, 5449 2 o 24
These e ec s can be e en mo e se e e in child en, depending on hei s age o de el-
opmen , nega i ely impac ing cogni i e de elopmen [
13
], as well as causing he diseases
men ioned ea lie . Child en spend a conside able pa o he day a school, whe e, in
addi ion o he abo e, a high concen a ion o CO
2
in he en i onmen can educe s uden s’
concen a ion le els and cogni i e pe o mance [14].
The e o e, adequa e en ila ion is essen ial in o de o ensu e indoo ai quali y and o
gua an ee he heal h and p ope de elopmen o child en [
15
,
16
]. This has been u he
highligh ed by he COVID-19 pandemic, emphasizing he need o en ila e spaces in o de
o p e en he ansmission o ai bo ne diseases [17,18].
Howe e , he high le el o in e es gene a ed in his ield ollowing he COVID-19
pandemic has sidelined an issue ha had been gaining ac ion p io o COVID-19, ha o
he mal s ess, which has now been elega ed o a seconda y posi ion. I cu en a es o
an h opogenic ac i i y pe sis , i is highly likely ha clima e change will lead o an inc ease
in he plane ’s a e age empe a u e o 1.5
◦
C abo e cu en le els be ween 2030 and 2052
and 4.8
◦
C be ween 2081 and 2100 [
19
], u he exace ba ing he issue o o e hea ing and i s
impac on indoo en i onmen s [
20
]. This, in u n, nega i ely a ec s he mal com o and
indoo ai quali y [
21
], especially in wa me sou he n Eu opean clima es [
22
], inc easing
he mal s ess [
23
]. Educa ional buildings a e especially ulne able o o e hea ing due o
signi ican in e nal occupancy loads on he one hand, and on he o he hand, o he ac ha
many ail o mee he mal condi ioning equi emen s, as hey we e buil p io o cu en
egula ions. In Eu ope, hese ma e s a e egula ed by Di ec i e 2010/31/EU (amended
by Di ec i e (EU) 2018/844) [
24
]. Fu he mo e, in mos schools, en ila ion is ca ied ou
na u ally, helping o educe le els o CO
2
and o he pollu an s while also p omo ing ene gy
consump ion educ ion [
25
]. This na u al en ila ion misuse is a guably he main cause o
discom o and he mal s ess [
26
], aking he o m o cold in win e and hea in summe ,
esul ing in a ise o up o 0.8
◦
C on a e age du ing he summe . The e o e, no only does
ai pollu ion impac nega i ely on child en’s heal h, bu he mal s ess also con ibu es o
ad e se e ec s such as concen a ion loss, a igue, i edness, anxie y, and s ess [27].
In many cases, his inc eased need o en ila ion has led o s udies on how o sol e
com o and he mal s ess issues being cas aside. Fu he mo e, in some cases hese issues
ha e wo sened due o he p io i y gi en o window opening wi h no p o ocol o con ol,
so ha ul ima ely hese emain open h oughou he day, o he de imen o he mal
com o [28,29].
The e o e, i is essen ial o iden i y en ila ion s a egies, whe he na u al o me-
chanical, o ensu e bo h ai quali y and use he mal com o . In his s udy, indoo ai
quali y is assessed h ough ca bon dioxide (CO
2
) concen a ion, which is commonly
used as a ep esen a i e indica o o en ila ion e ec i eness and o e all ai quali y in
occupied spaces [
30
,
31
]. Ele a ed CO
2
le els a e associa ed wi h insu icien en ila ion,
and con olling his pa ame e indi ec ly helps main ain adequa e le els o o he indoo
pollu an s. Fu he mo e, since p ope en ila ion is a key s a egy o educe ai bo ne i us
ansmission, moni o ing and limi ing CO
2
concen a ions also con ibu es o minimizing
his isk [
32
,
33
]. As o he mal com o , i is assessed based on empe a u e and ela i e
humidi y, ollowing he c i e ia es ablished in he ISO 7730 s anda d [34].
Re iews join ly add essing hese opics— en ila ion s a egies in schools and he mal
com o —ha e been sough . Howe e , despi e he ex en o his p oblem, ew e iews
ha e been ound which p esen a se o en ila ion s a egies and hei esul s ega ding
he mal com o . In he Scopus and WoS da abases, only se en e iews ha e been ound
discussing bo h opics combined, compa ed o 40 e iews ound add essing he opics
sepa a ely; 29 o hese ocus on en ila ion s a egies, albei only gua an eeing CO
2
le els
and ai quali y a he han he mal com o , while 11 emphasized he mal com o analysis
Appl. Sci. 2025,15, 5449 3 o 24
wi hou es ablishing o quan i ying en ila ion s a egies, only analyzing he causes. As
we ha e seen p e iously, his lack o e iews add essing bo h opics join ly may be due
o he cu en con ex ollowing he COVID-19 pandemic, whe e s udies ha e p ima ily
ocused on ai quali y o sa egua d human heal h by p e en ing disease ansmission
and exposu e o pollu an s. In addi ion o showing us he lack o e iews o conduc an
umb ella e iew s udy, his ini ial sea ch and analysis o s udies highligh s he need o a
e iew o a icles add essing hese opics o sea ch o en ila ion s a egies and analyze
hei esul s, s eng hs, limi a ions, and weaknesses in o de o c ea e p o ocols o use and
e alua ion in schools.
2. Ma e ials and Me hods
The pu pose o his s udy is o p esen a c i ical analysis o en ila ion s a egies
implemen ed in school en i onmen s and aimed a ensu ing s uden s’ he mal com o . To
do so, s a egies p oposed in p e ious s udies we e iden i ied and analyzed o es ablish hei
indi idual associa ed ad an ages and bene i s. This e alua ion was conduc ed h ough a
e iew o he li e a u e, implemen ing de ailed sea ch c i e ia as speci ied in Sec ion 2.1.
These c i e ia include he selec ion o ele an keywo ds and a sea ch o a icles by yea o
publica ion in wo speci ic da abases. Sec ion 2.2 ou lines he selec ion c i e ia employed:
an ini ial il e ing p ocess based on he a icle i le, ollowed by an analysis o he abs ac ,
and a inal de ailed examina ion o he a icle con en .
2.1. Sea ch C i e ia
The sea ch c i e ia began wi h he selec ion o keywo ds ela ed o he main objec i e
o he esea ch. The keywo ds chosen ini ially we e “ en ila ion” AND “school” AND
“ he mal com o ” AND “s a egy”. To complemen he in o ma ion, simila keywo ds
we e p oposed o b oaden he sea ch ange:
•“ en ila ion” OR “indoo ai ” OR “ai eno a ion” OR “ai low”
•“school” OR “uni e si y” OR “educa ional building” OR “class oom”
•“ he mal com o ” OR “occupan com o ” OR “en i onmen al com o ” OR “indoo
com o ” OR “en i onmen al quali y”
•
“s a egy” OR “ echnique” OR “me hodology” OR “model” OR “mode” OR “design”
Due o he ocus on na u al en ila ion s a egies du ing he COVID-19 pandemic,
o en neglec ing occupan s’ com o , he sea ch was di ided in o wo pe iods, be o e and
a e COVID-19, o educe po en ial bias. The in e media e yea was ixed a 2021. The
p e-COVID-19 pe iod ends in 2021 and goes back en yea s (2011–2021). The pos -COVID-
19 pe iod is de ined as 2022 o he p esen . Gi en ha his esea ch ocuses on schools,
he sea ch c i e ia we e e ined o include only educa ional buildings. Class ooms exhibi
dis inc cha ac e is ics, including highe occupancy densi ies, ixed and in ensi e schedules,
a mo e ulne able popula ion, and p edominan ly na u al en ila ion sys ems wi h limi ed
o no mechanical en ila ion o ai condi ioning. These ac o s di e en ia e educa ional
buildings om o he ypologies and necessi a e ailo ed app oaches.
The sea ch was conduc ed in wo di e en da abases, WOS and SCOPUS, which a e
main da abases used in o he e iews [
35
,
36
]. These da abases p o ide ad anced sea ch
unc ionali ies ha enable he au oma ed gene a ion o combina ions be ween keywo ds
and hei synonyms, allowing o a comp ehensi e and consis en sea ch p ocess. In bo h
cases, he sea ch was pe o med o he p oposed keywo ds in he i le, abs ac , and
keywo ds, limi ing he da e ange o each pe iod. These sea ch c i e ia a e shown in
Figu e 1.
Appl. Sci. 2025,15, 5449 4 o 24
Appl. Sci. 2025, 15, x FOR PEER REVIEW 4 o 25
keywo ds, limi ing he da e ange o each pe iod. These sea ch c i e ia a e shown in Fig-
u e 1.
Figu e 1. Me hodology: sea ch c i e ia.
2.2. Selec ion C i e ia
Once he abo e c i e ia we e es ablished, he sea ch o a icles was conduc ed using
he keywo ds speci ied. In o al, 277 a icles we e ob ained: 186 om he p e-COVID-19
pe iod and 91 om he pos -COVID-19 pe iod. O he 186 p e-COVID-19 a icles, 50 we e
ound in he SCOPUS da abase and 136 in WOS. Fo he pos -COVID-19 a icles, 32 we e
ound in SCOPUS and 59 in WOS.
Subsequen ly, an analysis was ca ied ou in o de o elimina e duplica e a icles
om hese wo da abases. A e excluding duplica es, 163 a icles om he p e-COVID-
19 pe iod and 74 om he pos -COVID-19 pe iod we e selec ed, so ha a o al o 237 a i-
cles we e selec ed acco ding o he ini ial sea ch c i e ia.
To suppo he selec ion p ocess, a co-occu ence map was gene a ed using
VOS iewe (Figu e 2), which e ealed i e main hema ic clus e s: he mal com o
(g een), na u al en ila ion and a chi ec u al design ( ed), indoo ai quali y (blue), edu-
ca ional con ex (yellow), and school building e o i ing (pu ple). VOS iewe is de el-
oped by Leiden Uni e si y, loca ed in Leiden, The Ne he lands. This mapping allowed
o a clea e unde s anding o he hema ic s uc u e wi hin he da ase and was used o
guide he iden i ica ion o he mos ele an a icles— hose si ua ed a he in e sec ion o
he main clus e s and add essing he ou co e concep s: en ila ion, school, he mal com-
o , and s a egy. F om he e, a il e ing p ocess began, ini ially selec ing a icles based on
hei i les. The i les o all ex ac ed a icles we e e iewed, selec ing hose whose i les
include aspec s ela ing o he objec i es se ou in his e iew. This selec ion yielded 56
a icles om he p e-COVID-19 block and 24 om he pos -COVID-19 block, o a o al o
80 a icles.
F om hese 80 a icles, a new selec ion was ca ied ou based on he abs ac s. All he
abs ac s o he chosen a icles we e e iewed, and hose which e e o en ila ion s a -
egies in schools and include he mal com o we e selec ed. Acco ding o he exclusion
Figu e 1. Me hodology: sea ch c i e ia.
2.2. Selec ion C i e ia
Once he abo e c i e ia we e es ablished, he sea ch o a icles was conduc ed using
he keywo ds speci ied. In o al, 277 a icles we e ob ained: 186 om he p e-COVID-19
pe iod and 91 om he pos -COVID-19 pe iod. O he 186 p e-COVID-19 a icles, 50 we e
ound in he SCOPUS da abase and 136 in WOS. Fo he pos -COVID-19 a icles, 32 we e
ound in SCOPUS and 59 in WOS.
Subsequen ly, an analysis was ca ied ou in o de o elimina e duplica e a icles om
hese wo da abases. A e excluding duplica es, 163 a icles om he p e-COVID-19 pe iod
and 74 om he pos -COVID-19 pe iod we e selec ed, so ha a o al o 237 a icles we e
selec ed acco ding o he ini ial sea ch c i e ia.
To suppo he selec ion p ocess, a co-occu ence map was gene a ed using VOS iewe
(Figu e 2), which e ealed i e main hema ic clus e s: he mal com o (g een), na u al en-
ila ion and a chi ec u al design ( ed), indoo ai quali y (blue), educa ional con ex (yellow),
and school building e o i ing (pu ple). VOS iewe is de eloped by Leiden Uni e si y,
loca ed in Leiden, The Ne he lands. This mapping allowed o a clea e unde s anding o
he hema ic s uc u e wi hin he da ase and was used o guide he iden i ica ion o he
mos ele an a icles— hose si ua ed a he in e sec ion o he main clus e s and add essing
he ou co e concep s: en ila ion, school, he mal com o , and s a egy. F om he e, a
il e ing p ocess began, ini ially selec ing a icles based on hei i les. The i les o all
ex ac ed a icles we e e iewed, selec ing hose whose i les include aspec s ela ing o he
objec i es se ou in his e iew. This selec ion yielded 56 a icles om he p e-COVID-19
block and 24 om he pos -COVID-19 block, o a o al o 80 a icles.
Appl. Sci. 2025,15, 5449 5 o 24
Appl. Sci. 2025, 15, x FOR PEER REVIEW 5 o 25
c i e ia ollowed in his pa , a icles ocusing on o he opics and ailing o add ess use s’
he mal com o o discuss en ila ion s a egies we e excluded. A icles mee ing he ex-
clusion c i e ia we e classi ied by opic, and se e al ecu ing hemes we e iden i ied. In
Table 1, he hemes iden i ied and he numbe o a icles associa ed wi h each a e lis ed.
As can be seen, one o he mos ecu ing hemes is he s udy o modi ica ion o he build-
ing en elope o imp o e he mal com o condi ions (46% o a icles), since one o he
keywo ds used, “s a egy”, also e e s o o ms o e o i ing. A e applying he a o e-
men ioned selec ion and exclusion c i e ia, 20 p e-COVID-19 and 9 pos -COVID-19 a i-
cles we e selec ed, o a o al o 29 a icles.
Figu e 2. Keywo d co-occu ence map gene a ed by VOS iewe wi h i e main hema ic clus e s:
he mal com o (g een), na u al en ila ion and a chi ec u al design ( ed), indoo ai quali y
(blue), educa ional con ex (yellow), and school building e o i ing (pu ple).
Table 1. Main opics o excluded a icles.
Causes o discom o 6
Changes o s udy o he building en elope/building e o i ing 22
Ene gy use 8
New simula ion models 2
Ai quali y analysis 9
Use pe cep ion 1
Finally, a selec ion based on he con en o he a icle was conduc ed. The 29 a icles
selec ed by abs ac we e analyzed, iden i ying a icles ha mee he ollowing equi e-
men s:
• p opose and analyze a leas one na u al and/o mechanical en ila ion s a egy.
Figu e 2. Keywo d co-occu ence map gene a ed by VOS iewe wi h i e main hema ic clus e s:
he mal com o (g een), na u al en ila ion and a chi ec u al design ( ed), indoo ai quali y (blue),
educa ional con ex (yellow), and school building e o i ing (pu ple).
F om hese 80 a icles, a new selec ion was ca ied ou based on he abs ac s. All he
abs ac s o he chosen a icles we e e iewed, and hose which e e o en ila ion s a egies
in schools and include he mal com o we e selec ed. Acco ding o he exclusion c i e ia
ollowed in his pa , a icles ocusing on o he opics and ailing o add ess use s’ he mal
com o o discuss en ila ion s a egies we e excluded. A icles mee ing he exclusion
c i e ia we e classi ied by opic, and se e al ecu ing hemes we e iden i ied. In Table 1,
he hemes iden i ied and he numbe o a icles associa ed wi h each a e lis ed. As can be
seen, one o he mos ecu ing hemes is he s udy o modi ica ion o he building en elope
o imp o e he mal com o condi ions (46% o a icles), since one o he keywo ds used,
“s a egy”, also e e s o o ms o e o i ing. A e applying he a o emen ioned selec ion
and exclusion c i e ia, 20 p e-COVID-19 and 9 pos -COVID-19 a icles we e selec ed, o a
o al o 29 a icles.
Table 1. Main opics o excluded a icles.
Causes o discom o 6
Changes o s udy o he building en elope/building e o i ing 22
Ene gy use 8
New simula ion models 2
Ai quali y analysis 9
Use pe cep ion 1
Finally, a selec ion based on he con en o he a icle was conduc ed. The 29 a icles se-
lec ed by abs ac we e analyzed, iden i ying a icles ha mee he ollowing equi emen s:
Appl. Sci. 2025,15, 5449 6 o 24
•p opose and analyze a leas one na u al and/o mechanical en ila ion s a egy.
•a e conduc ed in an educa ional building.
•conside he mal com o h ough moni o ing and/o su eys.
A e pe o ming hese analyses, 27 a icles we e selec ed: 17 p e-COVID-19 and 10
pos -COVID-19.
The numbe o a icles ex ac ed in each selec ion phase is lis ed in Table 2and Figu e 3.
Table 2. Numbe o a icles acco ding o il e ing phase.
Sea ch Fi s Selec ion
by Ti le
Second Selec ion
by Abs ac
Final
Selec ion
SCOPUS PRE 50 31 14 13
POST 19 12 6 7
WOS PRE 113 25 6 4
POST 55 12 3 3
To al 237 80 29 27
Appl. Sci. 2025, 15, x FOR PEER REVIEW 6 o 25
• a e conduc ed in an educa ional building.
• conside he mal com o h ough moni o ing and/o su eys.
A e pe o ming hese analyses, 27 a icles we e selec ed: 17 p e-COVID-19 and 10
pos -COVID-19.
The numbe o a icles ex ac ed in each selec ion phase is lis ed in Table 2 and Figu e
3.
Table 2. Numbe o a icles acco ding o il e ing phase.
Sea ch Fi s Selec ion by Ti le Second Selec ion by Abs ac Final Selec ion
SCOPUS PRE 50 31 14 13
POST 19 12 6 7
WOS PRE 113 25 6 4
POST 55 12 3 3
To al 237 80 29 27
Figu e 3. Me hodology: selec ion c i e ia.
Figu e 3. Me hodology: selec ion c i e ia.
Appl. Sci. 2025,15, 5449 7 o 24
A e e iewing he 27 a icles selec ed, an addi ional 8 we e excluded, as hey did no
p o ide he necessa y in o ma ion o mee he objec i es o his s udy. Consequen ly, he
analysis ocuses on he esul s om he emaining 19 a icles, which examined en ila ion
s a egies in school buildings, while also conside ing he mal com o .
3. Resul s
Se e al s udies ocus on di e en en ila ion s a egies o ensu e he mal com o
in school buildings. Table 3summa izes hese s udies, adding insigh on he ype o
en ila ion s udied and he key aspec s o he main selec ed a icles (yea o execu ion,
loca ion and clima e, ype o building, and season o he yea when es s and measu emen s
a e ca ied ou ).
Table 3. Summa y o he a icles whose en ila ion s a egies we e analyzed in dep h.
Re Yea Loca ion (Köppen
Clima ic Classi ica ion)
Type o
Building
Season o
he Yea Ven ila ion S a egy
[37] 2018 Goiânia, B azil (Aw) Uni e si y Summe
•Na u al en ila ion wi h cons an
window opening
•Mechanical en ila ion wi h
a iable low acco ding o senso s
[38] 2014 La Rochelle, F ance
(C b) Uni e si y Summe
Win e
•Na u al en ila ion wi h andom
window opening
•Na u al en ila ion wi h window
opening based on senso s
•Hyb id en ila ion
[39] 2019 Nicosia, Cyp us (Bsh) Seconda y
school Win e •Na u al en ila ion wi h
scheduled window opening
[40] 2020 Nicosia, Cyp us (Bsh) Seconda y
school
Summe
Win e
•Na u al en ila ion wi h
scheduled window opening
[41] 2019 Bucha es , Romania
(D )
Seconda y
school
Summe
Win e
•Na u al en ila ion wi h
scheduled window opening
[42] 2014 Uni ed Kingdom (C b) Seconda y
school Summe •Na u al en ila ion using
windca che
[43] 2017 Lisbon, Po ugal (Csa) Seconda y
school Annually
•Na u al en ila ion wi h andom
window opening
•Mechanical en ila ion wi h
a iable low acco ding o senso s
[44] 2016 D ammen, No way
(D b)
Educa ional
building
Win e
Sp ing
•Mechanical en ila ion wi h
a iable low acco ding o senso s
[45] 2019 Se ille, Spain (Csa) Seconda y
school
Summe
Win e
Sp ing
•Mechanical en ila ion wi h
cons an low
•Mechanical en ila ion wi h
a iable low acco ding o senso s
Appl. Sci. 2025,15, 5449 8 o 24
Table 3. Con .
Re Yea Loca ion (Köppen
Clima ic Classi ica ion)
Type o
Building
Season o
he Yea Ven ila ion S a egy
[46] 2023 Basque Coun y, Spain
(C b) Uni e si y
Summe
Win e
Sp ing
•Na u al en ila ion wi h cons an
window opening
•Na u al en ila ion wi h window
opening based on senso s
•Mechanical en ila ion wi h
a iable low acco ding o senso s
•Hyb id en ila ion
[47] 2022 Ex emadu a, Spain
(Csa) Uni e si y Win e
•Na u al en ila ion wi h cons an
window opening
•Na u al en ila ion wi h window
opening based on senso s
[48] 2024 G az, Aus ia (C b) Uni e si y Win e
Sp ing
•Na u al en ila ion wi h cons an
window opening
•Na u al en ila ion wi h
scheduled window opening
•Mechanical en ila ion wi h
cons an low
[49] 2011 Ancona, I aly (C a) Technical
School Win e
•Na u al en ila ion wi h andom
window opening
•Na u al en ila ion wi h window
opening based on senso s
•Na u al en ila ion using
windca che
•Mechanical en ila ion wi h
cons an low
[50] 2019 Cassino, I aly (Csa) P ima y
School Win e
•Na u al en ila ion wi h
scheduled window opening
•Mechanical en ila ion wi h
a iable low acco ding o senso s
[51] 2020 Jo dan (Bsk) Uni e si y Summe
Win e
•Na u al en ila ion using s ack
en ila ion
[52] 2023 Sou he n Sweden (C b) P ima y
School Summe
•Mechanical en ila ion wi h
cons an low
•Hyb id en ila ion
[53] 2023 Uni ed Kingdom (C b) Educa ional
building
Win e +
Sp ing
•Na u al en ila ion wi h andom
window opening
•Mechanical en ila ion wi h
cons an low
•Hyb id en ila ion
[54] 2023 Spain (Csa)
P ima y/seconda y
schools
Summe
Win e
Sp ing
•Na u al en ila ion wi h andom
window opening
[55] 2021 Sydney (C a) Seconda y
school
Win e
Sp ing
•Mechanical en ila ion wi h
a iable low acco ding o senso s
Appl. Sci. 2025,15, 5449 9 o 24
Below a e he a icles published by yea in Figu e 4and by coun y in Figu e 5. As can
be seen, he publica ion end does no inc ease as a esul o COVID-19, which is consis en
wi h he ini ial assessmen made, s a ing ha , a e COVID-19, mos o he a icles ocused
on ai quali y, lea ing aside he mal com o . In e ms o he coun ies whe e hese s udies
ha e been ca ied ou , mos (84%) ha e been conduc ed in Eu ope, and wi hin his g oup
he e is a no able p esence o he coun ies o Spain and I aly.
Appl. Sci. 2025, 15, x FOR PEER REVIEW 8 o 25
• Na u al en ila ion wi h window opening based on
senso s
[48] 2024 G az, Aus ia (C b) Uni e si y Win e
Sp ing
• Na u al en ila ion wi h cons an window opening
• Na u al en ila ion wi h scheduled window open-
ing
• Mechanical en ila ion wi h cons an low
[49] 2011 Ancona, I aly (C a) Technical
School Win e
• Na u al en ila ion wi h andom window opening
• Na u al en ila ion wi h window opening based on
senso s
• Na u al en ila ion using windca che
• Mechanical en ila ion wi h cons an low
[50] 2019 Cassino, I aly (Csa) P ima y
School Win e
• Na u al en ila ion wi h scheduled window open-
ing
• Mechanical en ila ion wi h a iable low acco d-
ing o senso s
[51] 2020 Jo dan (Bsk) Uni e si y Summe
Win e • Na u al en ila ion using s ack en ila ion
[52] 2023 Sou he n Sweden (C b) P ima y
School Summe • Mechanical en ila ion wi h cons an low
• Hyb id en ila ion
[53] 2023 Uni ed Kingdom (C b) Educa ional
building
Win e +
Sp ing
• Na u al en ila ion wi h andom window opening
• Mechanical en ila ion wi h cons an low
• Hyb id en ila ion
[54] 2023 Spain (Csa)
P ima y/sec-
onda y
schools
Summe
Win e
Sp ing
• Na u al en ila ion wi h andom window opening
[55] 2021 Sydney (C a) Seconda y
school
Win e
Sp ing
• Mechanical en ila ion wi h a iable low acco d-
ing o senso s
Below a e he a icles published by yea in Figu e 4 and by coun y in Figu e 5. As
can be seen, he publica ion end does no inc ease as a esul o COVID-19, which is
consis en wi h he ini ial assessmen made, s a ing ha , a e COVID-19, mos o he a -
icles ocused on ai quali y, lea ing aside he mal com o . In e ms o he coun ies
whe e hese s udies ha e been ca ied ou , mos (84%) ha e been conduc ed in Eu ope,
and wi hin his g oup he e is a no able p esence o he coun ies o Spain and I aly.
Figu e 4. Dis ibu ion o he a icles analyzed acco ding o yea o publica ion.
Figu e 4. Dis ibu ion o he a icles analyzed acco ding o yea o publica ion.
Appl. Sci. 2025, 15, x FOR PEER REVIEW 9 o 25
Figu e 5. Classi ica ion o a icles acco ding o he coun y in which he s udy was conduc ed.
Based on he a icles selec ed and analyzed, a se ies o en ila ion s a egies is p e-
sen ed in Table 4, co e ing na u al, mechanical, and hyb id en ila ion. I should be no ed
ha na u al en ila ion is de ined as en ila ion in which bo h in ake and ex ac ion a e
ca ied ou na u ally, while mechanical en ila ion is en ila ion in which bo h in ake and
ex ac ion a e ca ied ou mechanically, o in which in ake is na u al and ex ac ion is
mechanical. Finally, hyb id en ila ion is en ila ion in which na u al and mechanical
en ila ion a e in simul aneous ope a ion. This means ha mechanical en ila ion has i s
own in ake and mechanical ex ac ion, wi h a con olled ai low and numbe o enewals,
while, in pa allel, he windows a e opened, ei he manually by he use s o mechanically.
This en ila ion is also e e ed o in some o he s udies as mixed o mixed-mode.
Table 4. Classi ica ion o diffe en en ila ion s a egies.
NV
1. Use -dependen na u al en ila ion: ope a ion elies en i ely on occupan beha io ; use s de-
cide when o manually open o close windows, wi hou a speci ic pa e n.
V: No need o au oma ion sys ems o echnical main enance.
D: High unce ain y in pe o mance; can be ineffec i e du ing ex eme wea he o when use s
misjudge he need o en ila ion.
1.a. Wi h pe manen ly open windows: windows emain open con inuously, ega dless o ou -
doo condi ions o occupancy le els.
1.b. Wi h i egula window opening pa e ns: windows a e opened spo adically, based on he
use ’s pe cep ion (e.g., eeling wa m o de ec ing odo s).
2. Use -dependen na u al en ila ion acco ding o es ablished window opening pa e ns: use s
ollow p ede ined window opening schedules o ules, based on ime o day.
V: G ea e p edic abili y and po en ially imp o ed pe o mance i use s a e educa ed.
D: S ill elies on consis en use beha io ; may no espond in eal ime o changing condi ions.
Figu e 5. Classi ica ion o a icles acco ding o he coun y in which he s udy was conduc ed.
Based on he a icles selec ed and analyzed, a se ies o en ila ion s a egies is p e-
sen ed in Table 4, co e ing na u al, mechanical, and hyb id en ila ion. I should be no ed
ha na u al en ila ion is de ined as en ila ion in which bo h in ake and ex ac ion a e
ca ied ou na u ally, while mechanical en ila ion is en ila ion in which bo h in ake and
ex ac ion a e ca ied ou mechanically, o in which in ake is na u al and ex ac ion is
mechanical. Finally, hyb id en ila ion is en ila ion in which na u al and mechanical
en ila ion a e in simul aneous ope a ion. This means ha mechanical en ila ion has i s
own in ake and mechanical ex ac ion, wi h a con olled ai low and numbe o enewals,
while, in pa allel, he windows a e opened, ei he manually by he use s o mechanically.
This en ila ion is also e e ed o in some o he s udies as mixed o mixed-mode.
Appl. Sci. 2025,15, 5449 16 o 24
Table 9. Na u al en ila ion p o ocols.
Ven ila ion S a egy
Re .
Numbe o
Di e en
P o ocols
De ailed P o ocols
Occupancy Moni o ed
(M)/Simula ed
(S)
Moni o ed
Days
Temp Humidi y CO
2
Season C oss
Ven ila ion Ai
Condi ioning Di e en Window
Opening Times A e
Tes ed
Nigh
Ven ila ion Di e en
Classes
S udied
Di e en
Buildings
S udied
O ien a ion
Yes No Yes No Yes No
1. Use -
dependen
a
[
37
]
2 Summe · · · · Sou heas 25 M 3 · ·
[
46
]
1 Sp ing · · · No hwes 36 S 1 · · ·
[
47
]
17 Win e · · · · No h 5 o 40 M 18 · · ·
[
48
]
2Win e · · · Sou hwes 20 S 1 · ·
Sp ing · · · Sou hwes 20 S 1 ·
b
[
38
]
2Summe · · · Sou h 30 M 20 · · ·
Win e · · · Sou h 30 M 20 · · ·
[
43
]
2
Annually
· · · No hSou h 25 M 550 · ·
[
49
]
1 Win e · · · N/D 21 M 21 ·
[
53
]
24 Win e +
Sp ing · · · · · · N/D 27 o 33 M 81 · · ·
[
54
]
1 Summe · · · · · N/D 11 o 28 M 150 · · ·
1 Win e · · · · · N/D 11 o 28 M 150 · · ·
1 Sp ing · · · · · N/D 11 o 28 M 150 · · ·
2. Use -dependen
acco ding o es ablished
window opening pa e ns
[
39
]
7 Win e · · · · · · · No h + Sou h 23 o 25 M 6/96 · · ·
[
40
]
7Summe · · · · · · · No h + Sou h 23 o 25 M 4 · ·
Win e · · · · · No h + Sou h 23 o 25 M 7 · ·
[
41
]
8Summe · · · · N/D 13 o 26 S N/D · · ·
Win e · · · · N/D 13 o 26 S N/D · · ·
[
48
]
2Win e · · · · Sou hwes 20 S 1 · ·
Sp ing · · · · Sou hwes 20 S 1 ·
[
50
]
2 Win e · · · · Eas 25 o 27 M 60 · ·
3. Use -
independen
wi h
pa ame e
con ol
h ough
senso s
CO2
[
46
]
1 Sp ing · · · No hwes 36 S 1 · · ·
[
47
]
1 Win e · · · No h 33 M 18 · · ·
[
49
]
1 Win e · · · N/D 21 M 21 · ·
Temp.
[
38
]
2Summe · · · Sou h 30 M 21 · · ·
Win e · · · Sou h 30 M 20 · · ·
[
46
]
3
Summe · · · No hwes 36 S 1 · · ·
Win e · · · No hwes 36 S 1 · · ·
Sp ing · · · No hwes 36 S 1 · · ·
4. Use -independen
using windca che
[
42
]
1 Summe · · · N/D 32 S N/D
[
49
]
1 Win e · · · N/D 21 M 21 ·
[
51
]
8Summe · · · No h 48 S 31 · · ·
Win e · · · No h 48 S 28 · · ·
Appl. Sci. 2025,15, 5449 17 o 24
Table 10. Mechanical en ila ion p o ocols.
Ven ila ion
S a egy
Re .
Numbe o
Di e en
P o ocols
De ailed p o ocols
Occupancy Moni o ed
(M)/Simula ed
(S)
Moni o ed
Days
Temp Humidi y
CO
2
Season
Ai Condi-
ioning Ai low
Hea
Reco e y Nigh
Ven ila ion Di e en
Classes
S udied
Di e en
Buildings
S udied O ien a ion
Yes No Yes No Yes No
5. Mechanical
en ila ion wi h
cons an ai low
[
45
]
6
Summe ·6.5 ACH/6.1 ACH · · Sou hwes 21 S 15
Win e ·6.5 ACH/6.1 ACH · · Sou hwes 21 S 15
Sp ing ·6.5 ACH/6.1 ACH · · Sou hwes 21 S 15
[
48
]
4Win e ·2.9–4.45 L/s (m2)· · · Sou hwes 20 S 1 · ·
Sp ing ·2.9–4.45 L/s (m2)· · · Sou hwes 20 S 1 ·
[
49
]
1 Win e ·134 m3/h ·N/D 21 M 21 ·
[
52
]
1 Summe ·N/D ·N/D N/D M 31 ·
[
53
]
2 Win e + Sp ing ·N/D · · N/D 30 M 81 ···
6. Mechanical
en ila ion wi h
a iable ai low
[
37
]
1 Summe · · · Sou heas 25 M 3 · ·
[
43
]
2 Yea · · · · No h/Sou h 25 M 550 · ·
[
44
]
3Win e · · · N/D N/D M 1 · ·
Sp ing · · · N/D N/D M 1 · ·
[
45
]
3
Summe · · · Sou hwes 21 S 15
Win e · · · Sou hwes 21 S 15
Sp ing · · · Sou hwes 21 S 15
[
46
]
1 Sp ing · · · No heas 36 S 1 · ·
[
50
]
1 Win e · · · Eas 25–27 M 60 · ·
[
55
]
1 Win e + Sp ing · · No heas 7–25 M 60 ···
Table 11. Hyb id en ila ion p o ocols.
Ven ila ion
S a egy
Re .
Numbe o
Di e en
P o ocols
De ailed p o ocols
Occupancy
Moni o ed
(M)/Simula ed
(S)
Moni o ed
Days
Temp Humidi y CO
2
Na u al C oss
Ven ila ion Ai
Condi ioning Mechanical
Ven ila ion
Ai low (m3/h)
Hea
Reco e y Nigh
Ven ila ion
Di e en
Classes
S udied
Di e en
Buildings
S udied
O ien a ion
Season Yes No Yes No Yes No
Yes
No
7. Hyb id
en ila ion
[
38
]
4Summe · · 250 · · · · · Sou h 30 M 20 · · ·
Win e · · · 250 · · · · Sou h 30 M 32 · · ·
[
46
]
3
Summe · · 250 · · No hwes 36 S 1 · · ·
Win e · · 250 · · No hwes 36 S 1 · · ·
Sp ing · · 250 · · No hwes 36 S 1 · · ·
[
52
]
1 Summe · · N/D · · N/D N/D M 31 ·
[
53
]
4Win e +
Sp ing · · N/D · · · · N/D 31 M 81 · · ·
Appl. Sci. 2025,15, 5449 18 o 24
4. Discussion
This a icle in es iga es di e en en ila ion s a egies in educa ional cen e s and
hei abili y o simul aneously gua an ee ai quali y and hyg o he mal com o condi ions.
The 19 a icles selec ed we e used as he s a ing poin o an analysis o he condi ions
moni o ed in di e en seasons and clima es o each o he en ila ion s a egies conside ed.
The p o ocols used in each s udy ha e been analyzed and a de ailed s udy ca ied ou o
he measu emen s and condi ions in place. The esul s ob ained show he main pa ame e s
condi ioning he mal com o and ai quali y– empe a u e, humidi y, and CO2.
Due o he olume o da a ob ained om he a ailable li e a u e, es ablishing an equi alen
compa ison in he di e en clima ic zones is a di icul ask. This is no only because o he lack
o measu emen da a, bu also because he di e ences in p o ocols (spo measu emen s e sus
con inuous measu emen s, measu emen s only du ing occupied ime e sus measu emen s
h oughou he day) hampe compa ison o he di e en esul s. Fu he mo e, hyg o he mal
sensi i i y le els a y in he di e en clima ic zones. Howe e , a end can be iden i ied be ween
he di e en clima es and en ila ion s a egies. The e o e, his s udy does no aim o es ablish an
op imal p o ocol and en ila ion condi ions o ensu e he mal com o and ai quali y bu o c ea e
a guide which can be used o he pu poses o e e ence and compa ison in any u u e s udies.
In addi ion o he esul s p esen ed, his e iew e eals key ends and pa e ns ha
wa an u he e lec ion. Na u al en ila ion is by a he mos widely implemen ed
s a egy ac oss all clima es, likely due o i s low cos and ease o implemen a ion. Howe e ,
he high dependence on use beha io —especially in s a egies wi hou p ede ined window
opening schedules—makes i an un eliable solu ion o ensu ing consis en indoo en i on-
men al quali y. Mechanical en ila ion, on he o he hand, hough less equen ly s udied,
o e s g ea e con ol bu o en lacks he mal ea men o hea eco e y elemen s, which
limi s i s e ec i eness in colde clima es. Hyb id en ila ion s a egies, al hough leas
ep esen ed in he li e a u e, ha e shown p omising esul s in achie ing bo h accep able
CO
2
le els and he mal com o , pa icula ly when senso -based con ol is in ol ed. These
indings sugges ha au oma ion and mixed-mode sys ems could be a di ec ion o u u e
de elopmen , especially in egions whe e ou doo condi ions a y widely o whe e use
beha io canno be easily egula ed.
The esul s o he measu ed a iables— empe a u e, humidi y, and ca bon dioxide—
a e shown in Tables 10 and 11, de ailing a e age, maximum, and minimum alues. Only
win e and summe esul s a e analyzed, as hese a e he mos ex eme seasons in e ms o
he mal com o . As he ables show, no all s udies measu ed all a iables. In Table 10,
summe esul s, empe a u e alues o be ween 23 and 26
◦
C, humidi y be ween 45% and
60%, and CO
2
le els below 800 ppm a e highligh ed in g een ollowing he com o pa am-
e e s o he UNE EN ISO 7730:2006 [
56
] s anda d and ai quali y pa ame e s acco ding o
UNE EN 16798-1 [
57
]. In Table 11, win e esul s, empe a u e alues o be ween 20 and
24
◦
C, humidi y be ween 40% and 50%, and CO
2
le els below 800 ppm a e highligh ed
in g een.
As obse ed in Table 12, he e a e ew s a egies ha achie e op imal empe a u e and
CO
2
alues o ensu e he mal com o and ai quali y. I should be s essed ha he lack o
da a collec ion in many s udies complica es he analysis o he di e en s a egies. The e a e
h ee cases wo h highligh ing, as hey achie e an a e age empe a u e o be ween 23 and
25
◦
C and a e age CO
2
alues below 800 ppm. These h ee s a egies we e implemen ed in
he same s udy by Dhalluin e al. [
38
]. Sui able alues we e achie ed wi h use -con olled
na u al en ila ion wi hou any opening pa e n, wi h na u al en ila ion wi h window
opening based on empe a u e senso alues, and wi h hyb id en ila ion. I should be
no ed ha no ai condi ioning sys ems we e used o achie e op imal empe a u e alues
in any o hese cases. Howe e , due o he signi ican lack o da a, we canno asse ha
Appl. Sci. 2025,15, 5449 19 o 24
he emaining s a egies a e unsui able. I is he e o e necessa y o conduc u he s udies
wi h be e con ol o he a ious a iables which quan i y he mal com o and ai quali y.
Fu he mo e, Table 13 shows how he si ua ion in win e is simila o ha in summe .
Fi s ly, he lack o da a encoun e ed again in he bibliog aphy complica es compa ison
o esul s and s a egies. In his case, i is obse ed ha almos no scena io achie es
bo h adequa e he mal com o and ai quali y simul aneously. This is only ound in he
s udy by Cablé e al. [
44
] h ough a mechanical en ila ion s a egy wi h a iable low
based on senso measu emen s. In some scena ios whe e CO
2
alues below 800 ppm
a e achie ed, he empe a u e is comp omised, wi h a e age alues below 20
◦
C, e en
eaching ex emely low alues o 11
◦
C in some cases. Con e sely, in scena ios whe e
sui able a e age empe a u e alues a e achie ed, his is a he expense o CO
2
alues,
which can each up o 1400 ppm in some cases. The e o e, as in he p e ious case, i is
concluded ha u he s udies a e necessa y o inc ease he numbe o s a egies s udied
and he measu emen s aken.
A majo limi a ion ound in he e iewed li e a u e is he absence o s anda dized
moni o ing and epo ing p o ocols. Many s udies ail o speci y measu emen du a ions,
occupancy le els, o whe he he da a co espond o peak o a e age condi ions. This
lack o uni o mi y signi ican ly es ic s he po en ial o compa a i e o me a-analy ical
app oaches. Mo eo e , e y ew s udies epo on all h ee key a iables ( empe a u e,
humidi y, and CO
2
), making i di icul o assess s a egies holis ically. The obse ed pe o -
mance gaps, whe e ei he he mal com o o ai quali y is sac i iced o he o he , highligh
he complexi y o designing e ec i e passi e o semi-passi e en ila ion solu ions.
Finally, his e iew does no aim o de ine a uni e sal s a egy, bu a he o p o ide a
compa a i e and c i ical amewo k o u u e esea ch. I unde lines he need o mo e
obus expe imen al designs, b oade clima e co e age, and be e in eg a ion o com o
and heal h c i e ia. Mo e s udies a e needed, pa icula ly in unde ep esen ed clima e
zones and on unde explo ed s a egies like hyb id sys ems. Inco po a ing eal- ime da a
collec ion, use beha io modelling, and pos -pandemic conside a ions such as inc eased
ai enewal a es will also be essen ial in shaping u u e guidelines and ensu ing heal hy,
com o able lea ning en i onmen s.
Appl. Sci. 2025,15, 5449 20 o 24
Table 12. Resul s ob ained om he measu emen s acco ding o he di e en s a egies in summe . The alues shaded in g een a e hose ha mee he equi emen s
es ablished by egula ions ega ding CO2, empe a u e, and humidi y.
Ven ila ion
S a egy Clima e Re .
Cooling
Occupancy Moni o ed
(M)/Simula ed (S) Moni o ed
Days T A e age
(◦C) T Max (◦C) T Min (◦C) H A e age
(%) H Max (%) H Min (%)
CO
2
A e age
(ppm) CO2Max
(ppm) CO2Min
(ppm)
1a T opical [37] Yes 25 M 3 29.4 25.25 74 49
1b Oceanic [38] No 30 M 20 24.4 27.3 20.9 47 73 26 800 1800 300
Medi e anean [54] No 11 o 28 M 150 28.18 36.44 22.29 50.2 71.7 26.1 593 4015 341
2Semi-a id [40] No 23 o 25 M 4 31.6 33.7 28.5 32 50 19
Con inen al [41] No 13 o 26 S N/D 33.9 31.1 72 57 1300 875
3b Oceanic [38] No 30 M 20 23.5 28.4 19.7 50 76.5 30 700 1420 380
Oceanic [46] No 36 S 1 26.3 29.1 23.9 70 88 58 1079 2299 400
4Oceanic [42] No 32 S N/D
Semi-a id [51] No 48 S 31 33.75 64.5 23.75 459
5Medi e anean [45] No 21 S 15
Oceanic [52] No N/D M 31 23
6T opical [37] Yes 25 M 3 29 25.3 71 40
Medi e anean [45] No 21 S 15
7
Oceanic [38] No 30 M 20 24.95 24.35 24 43.5 60.75 28.75 500 965 220
Oceanic [46] No 36 S 1 26 28.6 23.8 41 45 38 688 1167 400
Oceanic [52] No N/D M 31 22.2
Table 13. Resul s ob ained om he measu emen s acco ding o he di e en s a egies in win e . The alues shaded in g een a e hose ha mee he equi emen s
es ablished by egula ions ega ding CO2, empe a u e, and humidi y.
Ven ila ion
S a egy Clima e Re .
Hea ing
Occupancy Moni o ed
(M)/Simula ed (S) Moni o ed
Days T A e age
(◦C) T Max (◦C) T Min (◦C) H A e age
(%) H Max (%) H Min (%)
CO
2
A e age
(ppm) CO2Max
(ppm) CO2Min
(ppm)
1a
Medi e anean
[47] No 5 o 40 M 18 16.1 17.0 15.4 56.5 59.5 54.6 539.5 607.8 479.4
Oceanic [48] Yes 20 S 1 17 15 770
1b
Oceanic [38] No 30 M 20 20.5 23.9 15.5 53 78 26.5 1800 3000 400
T opical [49] No 21 M 21 23.16 24.82 21.96
Medi e anean
[54] No 11 o 28 M 150 21.24 33.41 12.52 47 69.2 23.7 1194 4950 348
2
Semi-a id [39] Yes 23 o 25 M 6 20.6 22.3 18.2 58 71 45 1219 2632 419
Semi-a id [40] No 23 o 25 M 7 19.3 21.2 16.7 59 68 50
Con inen al [41] Yes 13 o 26 S N/D 21.9 17.1 36 18 1200 788
Oceanic [48] Yes 20 S 1 21 10 1450
Medi e anean
[50] No 25 o 27 M 60 23.3 24.2 21.0 1408 1943 645
3a
Medi e anean
[47] No 33 M 18 11.09 13.1 8.2 44.22 48.6 39.9 606.99 808 494
T opical [49] No 21 M 21 23.41 23.91 22.19 920.95
3b Oceanic [38] Yes 30 M 20 20.4 24.8 11 55 76 24.5 1100 2600 400
Oceanic [46] No 36 S 1 20 23.2 16.4 35 49 27 1091 2228 400
4T opical [49] No 21 M 21 21.61 23.71 21.62
Semi-a id [51] No 48 S 28 27.5 64 25.25 459
5
Medi e anean
[45] No 21 S 15
Oceanic [48] Yes 20 S 1 20 950
T opical [49] No 21 M 21 23.74 24.91 22.04
6
Con inen al [44] No N/D M 1 23.3 637
Medi e anean
[45] No 21 S 15
Medi e anean
[50] No 25 o 27 M 60 21.3 22.3 20.4 1002 1072 541
7Oceanic [38] Yes 30 M 32 20.3 26.45 13.2 39.25 58 21.25 775 1850 400
Oceanic [46] No 36 S 1 17.9 20.7 15.1 64 72 58 729 1158 400
Appl. Sci. 2025,15, 5449 21 o 24
5. Conclusions
This s udy has p esen ed a c i ical e iew which analyzed he en ila ion s a egies
mos commonly used in schools o bo h gua an ee indoo ai quali y and ensu e he he mal
com o o s uden s. A e an ini ial selec ion o 277 a icles and a inal selec ion o 19,
a o al o nine s a egies we e iden i ied in i e di e en clima es acco ding o Köppen’s
classi ica ion, g ouped by na u al, mechanical, o hyb id en ila ion. This highligh ed he
low numbe o s udies which ocus on ensu ing bo h he mal com o and ai quali y in
schools. I is also impo an o highligh he geog aphical concen a ion o he analyzed
s udies, wi h mos o hem being loca ed in Eu ope. Mos o he 80 s udies analyzed ini ially
add ess only one o hese aspec s, neglec ing he o he , pa icula ly he mal com o . Mos
s udies ocus on ensu ing ai quali y e en when his means sac i icing he mal com o .
This end has been pa icula ly p onounced since he COVID-19 pandemic, when he
ocus o s udies shi ed o ai quali y in o de o p e en ai bo ne disease ansmission,
i espec i e o he he mal com o o he occupan s. The e o e, a clea lack o s udies has
been iden i ied in his a ea.
Wi hin na u al en ila ion, he mos employed s a egies in s udies conside ing ai
quali y and he mal com o a e: use -dependen na u al en ila ion (wi h pe manen ly
open windows o wi h i egula window opening pa e ns); use -dependen na u al en-
ila ion acco ding o es ablished window opening pa e ns; use -independen na u al
en ila ion wi h pa ame e con ol h ough senso s (CO
2
o empe a u e senso s); and use -
independen na u al en ila ion using a windca che and s ack en ila ion. Mechanical
en ila ion s a egies can be summa ized as en ila ion wi h cons an ai low o en ila ion
wi h a iable ai low, wi h he la e based on CO
2
o empe a u e measu emen s. The e
a e no addi ional ca ego ies o mixed en ila ion s a egies.
Na u al en ila ion s a egies a e he mos used in all clima es: 73% in he con inen al
clima e, 68% in he Medi e anean clima e, 66% in he oceanic clima e, 100% in he semi-a id
clima e, and 63% in he opical clima e. Howe e , only in 17% o he cases analyzed in he
selec ed wo ks a e op imal a e age empe a u e and ai quali y condi ions achie ed wi h
hese s a egies in summe . None a e achie ed in win e , highligh ing a clea need o he
implemen a ion o hyb id o mixed sys ems in school spaces.
Rega ding he analysis o esul s ob ained wi h he di e en s a egies, i mus i s
be no ed ha he lack o da a p e en s us om de e mining whe he some s a egies a e
be e han o he s o he simul aneous p omo ion o he mal com o and ai quali y. A e
a compa ison o he s a egies ha ha e su icien da a on empe a u e and CO
2
, i is
concluded ha he e a e almos no s udies whe e bo h com o condi ions and CO
2
alues
a e ensu ed simul aneously; in mos cases, one o he wo a iables is comp omised. Only
wo s udies, one in summe and one in win e , ha e been ound o show sui able alues
o bo h pa ame e s. I is also wo h no ing a g ea e weal h o da a in win e , which
may seem su p ising, as some schools a e hea ed by adia o s bu a ely ha e cooling.
The e o e, summe could be mo e c i ical due o he high empe a u es in some o he
coun ies s udied, including Spain, I aly, and Po ugal. Howe e , in he es o Eu opean
coun ies, win e is he mos c i ical season, as hey ha e milde summe s. These issues
wa an u he in es iga ion in u u e s udies, as hey ep esen a ele an a ea o in e es
wi h di ec implica ions o indoo ai quali y (IAQ) and he mal com o (TC).
The e o e, i is essen ial o conduc new s udies es ing di e en en ila ion s a egies
in educa ional buildings o simul aneously ensu e he mal com o and ai quali y. This
e iew se es as a guide o he p o ocols used in he a ious s udies analyzed.
Appl. Sci. 2025,15, 5449 22 o 24
Au ho Con ibu ions: Concep ualiza ion, R.S. and Á.L.L.-R.; me hodology, M.T.A.-C. and R.M.L.-L.;
o mal analysis, M.T.A.-C. and R.M.L.-L.; in es iga ion, M.T.A.-C. and R.M.L.-L.; esou ces,
M.T.A.-C.
and R.M.L.-L.; w i ing—o iginal d a p epa a ion, M.T.A.-C. and R.M.L.-L.; w i ing— e iew and
edi ing, M.T.A.-C. and R.M.L.-L.; isualiza ion, M.T.A.-C. and R.M.L.-L.; supe ision, R.S. and
Á.L.L.-R.
; p ojec adminis a ion, R.S. and
Á.L.L.-R.
; unding acquisi ion, R.S. and Á.L.L.-R. All
au ho s ha e ead and ag eed o he published e sion o he manusc ip .
Funding: The au ho s wish o acknowledge he inancial suppo p o ided by G an (PID2020-
117722RB-I00) “Re o i en ila ion s a egies o heal hy and com o able schools wi hin a nea ly
ze o-ene gy building ho izon” unded by MICIU/AEI/10.13039/501100011033).
Ins i u ional Re iew Boa d S a emen : No applicable.
In o med Consen S a emen : No applicable.
Da a A ailabili y S a emen : No new da a we e c ea ed.
Con lic s o In e es : The au ho s decla e no con lic s o in e es .
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Asociación Española de No malización y Ce i icación. AENOR: Mad id, Spain, 2006.
57.
UNE-EN 16798-1:2020; Ene gy Pe o mance o Buildings. Ven ila ion o Buildings. Indoo En i onmen al Inpu Pa ame e s o
Design and Assessmen o Ene gy Pe o mance o Buildings Add essing Indoo Ai Quali y, The mal En i onmen , Ligh ing and
Acous ics—Module M1-6, Pa e 1. AENOR: Mad id, Spain, 2020.
Disclaime /Publishe ’s No e: The s a emen s, opinions and da a con ained in all publica ions a e solely hose o he indi idual
au ho (s) and con ibu o (s) and no o MDPI and/o he edi o (s). MDPI and/o he edi o (s) disclaim esponsibili y o any inju y o
people o p ope y esul ing om any ideas, me hods, ins uc ions o p oduc s e e ed o in he con en .
