Latest / Sunlight Matters / People, Buildings and Light

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People, Buildings and Light · Sunlight Matters

• 0:00
  SPEAKER_01: Actually, people don't want sunlight for its warmth anymore because probably because of the heat waves and and the change of how we live today.
• 0:09
  SPEAKER_01: So uh it is still important for the people.
• 0:12
  SPEAKER_01: It's important specifically actually for the effect on people's mood, on their well-being.
• 0:19
  SPEAKER_02: Um the building national code here in Sweden is removing a lot of requirements for new building, including minimum requirements from daylight, quite Sweden being in the forefront of the past.
• 0:29
  SPEAKER_02: And this is terrible, it's going in towards another direction compared to what research and what evidence is showing.
• 0:39
  SPEAKER_00: Welcome to Sunlight Matters, the podcast that reconnects us with the sun.
• 0:44
  SPEAKER_00: Join us as we explore the power and influence of our star, the force at the heart of everything.
• 0:50
  SPEAKER_00: Each episode we speak with leading experts to uncover the ways sunlight shapes our world.
• 0:57
  SPEAKER_03: Welcome to today's episode of Sunlight Matters, and I am joined by Nico and Aga from Lund University in Sweden.
• 1:06
  SPEAKER_03: So welcome both of you.
• 1:08
  SPEAKER_03: I wonder if you could both do a short introduction to yourselves, and then we're going to talk about my favorite subject, sunlight.
• 1:15
  SPEAKER_01: Thank you, David.
• 1:16
  SPEAKER_01: Thank you for having us in this show.
• 1:18
  SPEAKER_01: My name is Agnieszka Tahura.
• 1:20
  SPEAKER_01: I am a doctoral student at Lund University.
• 1:23
  SPEAKER_01: We work in a group called Energy and Building Design.
• 1:26
  SPEAKER_01: And my research, which is funded by the Swedish Energy Agency, focuses on solar access in cities.
• 1:35
  SPEAKER_01: And my personal interest is not only how the numbers can describe this solar axis, uh you know, and how much of it we're getting for the technical purposes like the energy and other technical performances, but also how it affects the people and what the people need and think about it.
• 1:58
  SPEAKER_03: Fantastic.
• 1:59
  SPEAKER_03: Fantastic.
• 2:00
  SPEAKER_02: And I'm Nico Gentile, and it happens to be that I'm the supervisor, one of the supervisors of uh Agniesca for uh her PhD, and I'm senior lecturer here, meaning that I do teaching, I do research mostly related to daylight, both inside and outside buildings, but also something else.
• 2:19
  SPEAKER_02: I'm a building physicist by background, so the energy part is also pretty important to me, together with more subjective or perceptual part that Taga is investigating quite a lot.
• 2:30
  SPEAKER_02: And thanks for inviting us.
• 2:32
  SPEAKER_03: Oh well, listen, I mean it's it's an absolute pleasure.
• 2:34
  SPEAKER_03: And I'm uh I love this because I think you know what what I sense is we're gonna have a great conversation around some of the more technical aspects, but also some of the more uh esoteric aspects of of sunlight and daylight, and actually that was one of the things I was kind of keen to start off with is there a difference in terms of the way you look at daylight versus sunlight?
• 3:00
  SPEAKER_03: I was just kind of interested because on a previous podcast that distinction was made to me, and I was like, Oh, it is interesting that that there is a distinction there.
• 3:10
  SPEAKER_01: Absolutely.
• 3:11
  SPEAKER_01: And in our field, uh when we talk about daylight, uh we mostly think about this diffuse light, the light that um comes in through the window, even if um even on a cloudy day, um it's this kind of soft light that just kind of makes the space feel bright and light, whereas sunlight is this direct beam of light.
• 3:35
  SPEAKER_01: So it's very strong, it creates shadows, um it can be very nice for some plants, and uh also people tend to love it, but it can be also quite problematic sometimes with uh the glare, and um because of its strength, it it can create uh some issues inside.
• 3:56
  SPEAKER_03: So when you're I mean, I guess when you're thinking about things like building buildings and people's relationship to buildings, then do you look at sunlight and daylight in two different ways, or do you see them as sort of one um part of the same thing?
• 4:12
  SPEAKER_01: So actually, in the regulations traditionally, daylight was looked at as a climate-less situation where we assume a um a cloudy sky.
• 4:24
  SPEAKER_01: So when the sky is cloudy, it's basically kind of special distribution where the zenith point, the most top point in our hemisphere, in the sky uh hemisphere is the brightest point.
• 4:38
  SPEAKER_01: This is a special case situation, and many recommendations for buildings for daylight assume this special case.
• 4:46
  SPEAKER_01: But nowadays we have advanced computer simulations, so we can we can simulate the real like case situation where the entire year is taken into account and both daylight and sunlight, so both the sunny days, the half-sunny days, the cloudy days are taken into account.
• 5:07
  SPEAKER_01: Um but on the other hand, you can also look at sunlight focusing just on the sunlight aspect.
• 5:14
  SPEAKER_01: So in that case, you check for the contact with the sun in the sky, so whether the sun can reach your building or not.
• 5:25
  SPEAKER_01: In that situation, you actually disregard clouds most of the time.
• 5:29
  SPEAKER_01: So there are different ways to assess the modern standards uh go towards the climate-based simulations, which are pretty advanced, but also there are there are aspects of sunlight that we can we can talk about separately to that, because then uh we talk about uh the solar access into the cities and buildings, and that's a little bit a different topic.
• 5:54
  SPEAKER_03: Yeah, I mean it's it's it's it's very interesting because I guess you know, as obvious is that you know the way sunlight hits buildings is very different.
• 6:02
  SPEAKER_03: In cities, you've got then, I guess, problems with high-rise buildings being built and people's access to sunlight um being impacted by that.
• 6:11
  SPEAKER_03: So in terms of sort of regulations around people's access to light, I know in the UK, for instance, we do have a right to light and things like that.
• 6:21
  SPEAKER_03: But uh, it's one of those things where I then get confused between does that mean daylight or sunlight, you know.
• 6:26
  SPEAKER_03: So would you be able to just sort of clear that up a bit?
• 6:30
  SPEAKER_01: Absolutely.
• 6:31
  SPEAKER_01: I I can tell you that uh for sunlight, there are these recommendations out there and they vary by country.
• 6:38
  SPEAKER_01: There is no uniform way to look at it.
• 6:40
  SPEAKER_01: But there's been some suggested ways.
• 6:42
  SPEAKER_01: Um, for example, China and Australia, they look at the worst day of the year.
• 6:48
  SPEAKER_01: So that it would be the winter solstice where the day is the shortest, and then they say we should have this many hours of sunlight access onto, for example, a window surface.
• 7:00
  SPEAKER_01: That doesn't ensure that on this particular day the sun will actually hit this window because it can be a cloudy day, but clouds are disregarded in that case.
• 7:10
  SPEAKER_01: So it's just about um the vectors, kind of it's the connection to the little dot on the sky, which is the the sun in that on the on that hour.
• 7:20
  SPEAKER_01: Many countries follow the same principle, the same methodology.
• 7:24
  SPEAKER_01: The European standard, for example, it requires that um at least one habitable space in an apartment, for example, gets one and a half hours of sunlight, and the design day is between the first of February and the 21st of March.
• 7:42
  SPEAKER_01: So they don't take the worst case scenario, they take the mid-worst case.
• 7:48
  SPEAKER_01: So the days are getting longer, but still the nights are shorter or equal to the day duration.
• 7:55
  SPEAKER_02: Yeah, I I think it's also important to understand why standards and regulation are there and where they come from.
• 8:01
  SPEAKER_02: So because otherwise, you know, we look at numbers and they don't really make sense to us.
• 8:05
  SPEAKER_02: But you know, a lot of daylight regulations that we have in Europe, daylight I'm speaking now, not uh not sunlight specifically, they come from the early 20s and this and even later, and they were done for sanitary purposes.
• 8:17
  SPEAKER_02: So having windows that could be open and that you could change air, and then and and then and then you eventually get daylight.
• 8:23
  SPEAKER_02: So for most of Europe, uh daylight meant having a regulation on minimum window sides for ears, which is very limited, of course.
• 8:32
  SPEAKER_02: And then daylight became important more for the appearance of room and the quality, but also for energy aspects like visibility and so on.
• 8:41
  SPEAKER_02: So we moved towards an approach that was more what Aga was mentioning, based on an overcast sky.
• 8:47
  SPEAKER_02: It's called daylight factor approach, which is a little bit limited, gives you a snapshot of a very specific situation.
• 8:53
  SPEAKER_02: But there again is done to have something that gives you an idea of how much the light for visibility you're getting inside the space.
• 9:01
  SPEAKER_02: So we are evolving from sanitary purposes to vision.
• 9:05
  SPEAKER_02: And then it comes sunlight.
• 9:07
  SPEAKER_02: So it's that the last I would say.
• 9:08
  SPEAKER_02: Sunlight it's it's important, it depends on the space.
• 9:11
  SPEAKER_02: Are we speaking about residential dwellings or are we speaking about non-residential?
• 9:16
  SPEAKER_02: And in dwellings, having sunlight has been connected to health benefits, it is very well connected to financial benefits as well.
• 9:24
  SPEAKER_02: We have research showing that the financial value of apartments both in um in North America, but also I've seen recently a study in Italy, it relates very well with the annual sunlight exposure, so to the direct sunlight.
• 9:40
  SPEAKER_02: So there is also these other aspects that come to the picture.
• 9:43
  SPEAKER_02: So that's that we discuss a lot about different aspects of daylight.
• 9:48
  SPEAKER_02: And when it comes to urban densification and right to light, as you say, uh this is extremely important we think nowadays to give a justification to the needs for sunlight at daylight, because for environmental reasons we are uh building more and more dense, which is perhaps good in a sustainability perspective, but it's uh um it's not aligned with daylight and sunlight goals.
• 10:11
  SPEAKER_03: Yeah, no, it's I it it's fast because it sort of feels that at some point along the way that kind of sunlight and daylight, you know, was really deprioritized in our kind of rush to build um through the sort of sixties and seventies and eighties, and and it's now being rediscovered as something very, very important.
• 10:30
  SPEAKER_03: And certainly what I can see is is around the kind of notion of sunlight, there's a lot more research being published around why it's absolutely vital.
• 10:40
  SPEAKER_03: And I was I was talking to someone from UCL last week who was saying that from an educational point of view, for instance, that if kids are taught in lighter classrooms, their ability to learn kind of goes up.
• 10:52
  SPEAKER_03: And uh Aga, you've just done a survey on on sunlight, and I was kind of to understand what some of the findings were that you got from that.
• 11:00
  SPEAKER_03: So, what were you looking to get out of the survey?
• 11:04
  SPEAKER_01: I actually was very interested to find out what people today think about sunlight because the latest the studies that I could find were dated back to the 60s and 70s on them.
• 11:17
  SPEAKER_01: Really?
• 11:17
  SPEAKER_01: Yeah, and uh not much has been done since.
• 11:21
  SPEAKER_01: Um so the I was wondering what is the basis for some of these recommendations, why the 1.5 hours uh in the European standard, for example, where does this come from?
• 11:34
  SPEAKER_01: And it seems like uh a lot of these uh numbers might be coming from a very old research, we could say now, because it was 50 years ago, and people were then valuing sunlight for its warmth, and because the actually the apartments were not as heated or as well heated as they are today.
• 11:55
  SPEAKER_01: Today, in the modern buildings, we have insulation, we have very good and airtight windows, we have district heating and all the modern technologies that um no longer make it such an issue.
• 12:08
  SPEAKER_01: Also, currently are experiencing more and more heat waves, and the cross-section of the society also changed.
• 12:16
  SPEAKER_01: We no longer have the same, you know, arrangements in families and and uh lots of migration has happened since.
• 12:24
  SPEAKER_01: So it was very interesting to look at the modern population and to see what they think about sunlight.
• 12:31
  SPEAKER_01: And I can tell you that it was actually similar because the old study said that 90% of people want sunlight in their homes, which is the case now as well.
• 12:41
  SPEAKER_01: But 20 something percent out of those people actually would want the sunlight inside only in the winter months.
• 12:50
  SPEAKER_01: So there is a little bit of a shift in perception.
• 12:53
  SPEAKER_01: Actually, people don't want sunlight for its warmth anymore because probably because of the heat waves and and the change of how we live today.
• 13:03
  SPEAKER_01: So uh it is still important for the people.
• 13:06
  SPEAKER_01: It's important specifically actually for the effect on people's mood, on their well-being.
• 13:13
  SPEAKER_01: This is a very, very important aspect of sunlight, I think.
• 13:17
  SPEAKER_01: The mood enhancing, people get energized by just seeing that the sun is shining outside.
• 13:24
  SPEAKER_01: And this is a fascinating uh effect that sunlight has on us.
• 13:28
  SPEAKER_01: And also, I I have to say that I was doing the survey in the spring months.
• 13:32
  SPEAKER_01: So people were, especially here in Sweden, people were craving for some sunlight after long cold dark months in Sweden.
• 13:42
  SPEAKER_03: Can I so can I ask in terms of uh how you did the research?
• 13:46
  SPEAKER_03: It was basically you came up with a series of questions and it was all going out asking for their response.
• 13:52
  SPEAKER_03: I mean, uh and it is fascinating.
• 13:54
  SPEAKER_03: You did it at the end of the winter into early spring, and you know, I I mean I know for myself I've become obsessional about please, son, come out, you know.
• 14:04
  SPEAKER_03: We've had a we've had a few good weeks.
• 14:06
  SPEAKER_03: Well, we've had a brilliant spring here in the UK, and I think it sort of made a massive difference to everybody.
• 14:12
  SPEAKER_03: So yeah, I I'm kind of how what was the sort of process he went through in terms of gathering that data?
• 14:18
  SPEAKER_03: And I I guess there was sort of like what you were looking for was kind of the answer to what people sort of feel about sunlight, wasn't it?
• 14:27
  SPEAKER_01: Yes, it was about people's perceptions, it was about their preferences also in regard to sunlight in home, so residential setting of sunlight.
• 14:39
  SPEAKER_01: And I largely based this research on those studies from the 60s and 70s in terms of their structure and what they asked about, and actually what they actually got as well from those interviews that they carried out because people were then talking about all these aspects of sunlight, like its appearance on room or these uh therapeutic benefits and so on.
• 15:01
  SPEAKER_01: So I included those in my survey as well, and I tried to adjust it so that it could be posted online.
• 15:08
  SPEAKER_01: So it's an online survey, it's actually still active.
• 15:12
  SPEAKER_01: I'm already analyzing the data for a given period, but uh you are also welcome to take taking it.
• 15:20
  SPEAKER_03: Absolutely, I'll be there.
• 15:22
  SPEAKER_01: But then I I'm kind of so will you then publish the results publicly or yes, I'm planning on uh publishing them uh in a conference paper, perhaps, which has been already the pay the proposal has been submitted.
• 15:37
  SPEAKER_01: Uh and then also as a journal paper, uh as part of a larger study, I also carried out interviews uh here in Sweden with uh participants in in homes um to to pick their brains a little bit more about uh how they interact with sunlight, how they feel and um yeah, what they think about the sunlight access that they receive in their apartments.
• 16:06
  SPEAKER_01: So it was more personalized.
• 16:08
  SPEAKER_01: I could look specifically at specific apartments and not only find out what people think about it, but also simulate the actual, you know, well, what is the situation there?
• 16:19
  SPEAKER_01: You know, how many hours are we getting?
• 16:21
  SPEAKER_01: So um I will I'll put that together and then I will have a bigger understanding, hopefully, of uh what is right.
• 16:30
  SPEAKER_02: And I think I think we can also mention, okay, you already got several hundreds of answers, which is very good.
• 16:36
  SPEAKER_02: It makes quite a strong case from all over Europe, of course, with a strong part of the population being Swedish all over Europe.
• 16:44
  SPEAKER_02: And we are in contact, of course, also with the European Standardization Committee, because the European standard for daylight has some requirements for sunlight access, and this probably can be slightly revised or updated.
• 16:59
  SPEAKER_02: I don't think, for what I see from your work, Aga, I don't see like big changes compared to what is recommended nowadays, but at least there will be a stronger evidence for delivering a certain amount of sunlight in dwellings.
• 17:12
  SPEAKER_03: Well, I mean I I have to say, I mean, congratulations on doing the work because you know, again, the more I understand about the absolute lack of research there is about sun and our relationship to the sun, the more profoundly strange I find it.
• 17:31
  SPEAKER_03: Because you know, if you're a government, actually having a healthy, fit population should be one of your top priorities.
• 17:41
  SPEAKER_03: And you know, the evidence points to people's relationship with the sun is is so incredibly important, and actually if you can ensure that they get access to sunlight in the proper and best way, then they're gonna be fitter, healthier, and and you know, more mental or mentally kind of able to deal with things.
• 18:02
  SPEAKER_03: So, you know, it is it's kind of a strange thing, isn't it?
• 18:05
  SPEAKER_03: I mean you talk about there hasn't been any research since the 60s or 70s.
• 18:09
  SPEAKER_03: I mean, that is quite surprising, isn't it?
• 18:12
  SPEAKER_01: Yes, it was surprising to me.
• 18:14
  SPEAKER_01: Um there is some research done, but it's not it often combines a lot of things, it doesn't focus particularly on sunlight, and it's not to this scale, you know.
• 18:24
  SPEAKER_01: I was trying to reach a good number of respondents from Sweden, so I got nearly 500 respondents, so I could then look at it as a good cross-section of the population and make some make some points from that.
• 18:41
  SPEAKER_02: Yeah, I I think also research goes a little bit in waves, depending on uh which is the evidence that we start to build.
• 18:48
  SPEAKER_02: And I mean lately there has been an enormous amount of research on daylight per se, and then it has been the view the wave of view out, and it's still the wave of view out because you know, in the moment in which maybe research shows that view out is quite important for restoration, for reducing psychological stress and so on, then of course, even us as building physicists or like architects, we focus our research on that.
• 19:12
  SPEAKER_02: But this has not been the case for sunlight per se, so the direct component on daylight, and I think it's about the time of investigating that as well.
• 19:24
  SPEAKER_02: Uh, if we look at the European standard again, I mean, even in that case, it comes a little bit clearer.
• 19:31
  SPEAKER_02: The European standard has four requirements for daylight in general.
• 19:35
  SPEAKER_02: One is about daylight provision, they call it.
• 19:38
  SPEAKER_02: So it's just granting enough daylight.
• 19:41
  SPEAKER_02: But then, of course, there is too much daylight, so there is a criterion glare.
• 19:46
  SPEAKER_02: And this was also very well developed because glare is a quite serious problem in offices, especially in Northern Europe, not in dwellings, of course.
• 19:55
  SPEAKER_02: Then there is a criteria based on view out, and the view out criteria is also quite well grounded on um on uh research because of psychological stress relief and so on.
• 20:07
  SPEAKER_02: And the fourth criteria is the sunlight access, which is there, so the European Standardization Committee experts they recognize it as of high importance, but still is, in our opinion, under-researched at the moment.
• 20:22
  SPEAKER_02: So, in that sense, I think Agar is doing an exceptionally good work in updating there and giving some more solid evidence.
• 20:28
  SPEAKER_03: It's really interesting.
• 20:30
  SPEAKER_03: I can't wait to see the f final kind of outputs from it.
• 20:33
  SPEAKER_03: I guess, Agar, overall, what you see is that people want people really value sunlight.
• 20:40
  SPEAKER_01: They do, they do, and it's got a very positive effect.
• 20:44
  SPEAKER_01: I could say that uh one thing that people maybe start uh maybe maybe this is changing with with the time and global warming, is that uh people maybe don't appreciate sunlight anymore for its warmth as much as they used to.
• 21:00
  SPEAKER_01: Right.
• 21:01
  SPEAKER_01: Interestingly, also there was this question, it was kind of like um a dilemma question asked in this survey, which people often say to me that this was the toughest to answer.
• 21:13
  SPEAKER_01: I give the participants the option of a nice view out, a pleasant view out, but with little or no sunlight inside, versus plenty of sunlight inside, but not such a nice view.
• 21:25
  SPEAKER_01: And actually the results suggest that uh two-thirds of people actually prefer to have a nice view versus to have plenty of sunlight.
• 21:36
  SPEAKER_01: So there is a little bit of shift towards towards a nice view.
• 21:40
  SPEAKER_01: And sunlight is an important factor, but it's not the most important factor.
• 21:46
  SPEAKER_01: There was also one question in the survey where people were rating different aspects of sunlight of um their apartments, but uh to to find out what what they value the most.
• 21:59
  SPEAKER_01: And they actually preferred daylight, lots of daylight to to lots of sunlight in their apartments.
• 22:07
  SPEAKER_01: But sunlight is still a very important aspect.
• 22:12
  SPEAKER_01: And in my interviews, my participants often talked about how it affects them, how it lifts their mood and uh you know gives them the energy kick in the morning and so on.
• 22:24
  SPEAKER_01: Often they also spoke about how they regret the lack of sunlight or that the room is too deep, so it doesn't reach all the way and so on.
• 22:33
  SPEAKER_02: You know who are the best researcher in this field.
• 22:35
  SPEAKER_02: Uh, they are real estate agents.
• 22:37
  SPEAKER_02: They are by far the best.
• 22:39
  SPEAKER_03: Yeah, yeah, yeah.
• 22:40
  SPEAKER_02: If you would read any ads for apartments that are on sale in Sweden, they would set as first thing loose of fresh, which means light and fresh, like west facing balcony.
• 22:52
  SPEAKER_02: So you get the afternoon sun.
• 22:54
  SPEAKER_02: And um uh another common expression is this uh what do you say in English?
• 23:00
  SPEAKER_02: But corner apartment, meaning that you get light from three sides.
• 23:04
  SPEAKER_02: Yes, yes, yes.
• 23:04
  SPEAKER_02: But they really know what the client wants.
• 23:06
  SPEAKER_02: And we are doing we are trying to put some evidence there, but I mean it would be enough to read their ad, in fact, to understand how important it is to light in dwellings.
• 23:15
  SPEAKER_03: I mean it's it's fascinating.
• 23:17
  SPEAKER_03: I mean, I the I I mean I think about my house, which is you know it's a beautiful house.
• 23:23
  SPEAKER_03: Um very fortunate because I've got an an office in the garden, so I've got access to lots of light and sunlight.
• 23:30
  SPEAKER_03: Um but it I I I was really interested in your distinction between kind of sunlight and the view.
• 23:36
  SPEAKER_03: And for me, sunlight is more important, I think, than the view, because I know sort of the impact it had lack of sunlight, the impact it has on me is something which I can kind of feel sort of physically almost.
• 23:49
  SPEAKER_03: So um it's fascinating to kind of hear the difference.
• 23:52
  SPEAKER_03: But Nico, from your experience though, this whole, you know, what why do people care about sort of daylight and sunlight?
• 23:59
  SPEAKER_03: What's the what's the sort of in again, the interplay between them like you know, just as a I guess from the sort of building physicist point of view, you know, it I guess you've got light coming into into buildings which may impact kind of heating, all these things.
• 24:19
  SPEAKER_03: What what what is the interplay, as I say, between them and why should people care?
• 24:24
  SPEAKER_02: Yeah, that's a good question.
• 24:25
  SPEAKER_02: Uh starting from the first, why people care, or why they should care, why the people care, I think, because intrinsically we know that that's what we should have.
• 24:34
  SPEAKER_02: Kind of we evolved with daylight and we evolved there.
• 24:37
  SPEAKER_02: So uh we we we just just want to have more of that, and we know that we are spending most of our life indoors.
• 24:44
  SPEAKER_02: So uh I mean that that's probably the easiest way to answer.
• 24:48
  SPEAKER_02: And then, of course, there are many other small angles to look at the point here.
• 24:52
  SPEAKER_02: Survey Aga here was mentioning something about the survey with view out, sunlight, and so on.
• 24:57
  SPEAKER_02: I can say that also people are getting more and more acquainted about the benefits of being exposed to daylight as research evidence builds up and as we get less and less daylight.
• 25:08
  SPEAKER_02: I think the pandemic, in a way, was quite uh enlightening there.
• 25:11
  SPEAKER_02: I would say that daylight is one of those things that you don't appreciate until someone takes it, takes it away from you.
• 25:19
  SPEAKER_03: Right, right, right, right.
• 25:20
  SPEAKER_02: So the pandemic there was quite an help.
• 25:23
  SPEAKER_02: So that's probably why people care already.
• 25:26
  SPEAKER_02: Why they should care, and this is instead a very long list.
• 25:30
  SPEAKER_02: So for me, for me as a building physicist, again, as you mentioned, it's um it's about a lot about trade-off.
• 25:37
  SPEAKER_02: Because daylight and sunlight indoors is not about having as much as possible.
• 25:43
  SPEAKER_02: Too much daylight, it's it's problematic in terms of overillumination.
• 25:47
  SPEAKER_02: You cannot uh really perform tasks like office tasks or fine work tasks.
• 25:53
  SPEAKER_02: It can be glaring and it can be also pretty bad for energy, so it's overheating.
• 25:58
  SPEAKER_02: So that's the first trade-off.
• 25:59
  SPEAKER_02: You have a little bit to balance the two things.
• 26:02
  SPEAKER_02: And this has been a problem for decades, I would say.
• 26:05
  SPEAKER_02: And nowadays it's getting even more complicated.
• 26:07
  SPEAKER_02: The picture is not really trivial at all to answer the question.
• 26:10
  SPEAKER_02: So, because today we don't care anymore about energy in buildings, energy during use phase, but we are looking more at uh the energy impact of buildings during their entire life cycle.
• 26:22
  SPEAKER_02: So, from the construction to the use to the disposal of buildings, and we look at energy in terms of climatic impact, embedded carbon typically.
• 26:32
  SPEAKER_02: Now the things here it gets even more complicated because building a window and using a window instead of having a wall, it can be more environmentally impacting than the wall in itself.
• 26:45
  SPEAKER_02: And if we don't balance the environmental performance with other types of benefits, let's say social benefits, health benefits, then um then we we have a big risk that we that we are gonna recommend in future buildings with less and less daylight because if we focus too much on the environmental aspect.
• 27:07
  SPEAKER_02: It's not the case, for example, that in Europe we have a framework for sustainability of construction works.
• 27:15
  SPEAKER_02: It's a framework that is based on the so-called three pillars of sustainability, the environmental sustainability, so how much CO2 you emit in the building, the social sustainability, which is about energy poverty, daylight poverty, and daylight is expressionally mentioned there.
• 27:33
  SPEAKER_02: So that's equal and the financial aspect as well, because there should be financial sustainability as well.
• 27:38
  SPEAKER_02: But in fact, despite having this framework, what we observe in reality is that all the regulation today, all the recommendations, like new climate declaration for buildings, new limits are based only on the environmental performance.
• 27:52
  SPEAKER_02: And there is very little said about the social or quality performance.
• 27:56
  SPEAKER_02: And this is a risk, and it's a clear risk.
• 27:58
  SPEAKER_02: I can mention, for example, that from 1st of July, um, the building national code here in Sweden is removing a lot of requirements for new building, including minimum requirements from daylight, despite Sweden being in the forefront in the past.
• 28:14
  SPEAKER_02: And this is terrible, it's going in towards another direction compared to what research and what evidence is showing.
• 28:21
  SPEAKER_02: So let's see how it turns out.
• 28:23
  SPEAKER_02: I don't think it's gonna be a great uh experiment, but that's um uh that's what is happening.
• 28:30
  SPEAKER_02: So this is uh yeah, this is something.
• 28:33
  SPEAKER_02: Uh we do quite a lot of studies there, I would say.
• 28:36
  SPEAKER_02: As Agas mentioned, the Swedish Energy Agency is supporting us a lot with that.
• 28:42
  SPEAKER_02: And we have uh we have some quite work, uh quite some work ongoing with the International Energy Agency as well, trying to look at this interplay and trade-offs between energy, environmental aspects, and quality, social sustainability.
• 28:57
  SPEAKER_03: I mean, I think it's so interesting because I I haven't heard that interplay being described so nicely before, and it really is something to consider.
• 29:06
  SPEAKER_03: And you know, again, I've been reading research which shows that since COVID people are spending less time outside, so you know, they're not getting access to sunlight and daylight and the the potential health-giving benefits of that they're inside, and you know, here am I, I'm sat in front of a huge piece of glass, but that glass is designed to to cut out UV and other things, so you know, I can sit here all day and I won't get some of the benefits of actually just standing outside, and as a sort of building physicist, is there things going on around kind of thinking about glass and you know, innovations around glass to actually let some of the kind of good stuff through as well?
• 29:51
  SPEAKER_03: Because if people are spending more time inside, then that's going to be very necessary.
• 29:55
  SPEAKER_03: And again, I was talking to someone in Dubai, and you know, Dubai.
• 30:00
  SPEAKER_03: I think a couple of weeks ago was up to 50 degrees, so you couldn't go outside your building or you know, but all of the buildings are covered, you know, have glass, all of the big buildings have glass, but all of those will be designed to keep UV and infrared out.
• 30:16
  SPEAKER_02: Yeah.
• 30:17
  SPEAKER_02: That's actually a very good question and very timely as well, because that's where research is moving as well now.
• 30:23
  SPEAKER_02: So I would say that until maybe 20 years ago, for like for us, daylight was about visible light, the one that we used to see.
• 30:30
  SPEAKER_02: And then then suddenly research shows that there are also non-visual effects of light related to sleep wake cycles.
• 30:37
  SPEAKER_02: So there has been a lot done in that uh in that area as well now, showing again how daylight and the spectral composition of daylight into the visible spectrum can um adjust, or rather than adjust, I would say keep in pace our sleep and wake cycles.
• 30:54
  SPEAKER_02: Um yeah, so I would say that until today we just focused on the visible part of light.
• 30:58
  SPEAKER_02: And because of that, we did uh windows and glass, as you say, that let all the visible light coming through, quite a lot of it, like 70% or just a little bit less, but they cut out completely UV and infrared radiation.
• 31:12
  SPEAKER_02: Infrared in particular, because it's the one problematic for overheating in buildings.
• 31:17
  SPEAKER_02: So it means that daylight indoors is actually different from the daylight outdoors.
• 31:22
  SPEAKER_02: So we have almost the same visible part, but we are lacking the UV and the infrared and other part of radiation.
• 31:29
  SPEAKER_02: Now it turns out that this is might be a big problem.
• 31:32
  SPEAKER_02: We don't know that yet.
• 31:34
  SPEAKER_02: But uh but there is more and more evidence showing that the infrared part of radiation is extremely important together with the UV for eye development and for a number of other developmental things that I don't want to mention and I don't want to get there because I'm not um a physiologist or a doctor, so it's outside my competence.
• 31:53
  SPEAKER_02: But what I do know I do know is that we need infrared radiation.
• 31:57
  SPEAKER_02: We are cutting it out completely because of energy reason, energy in buildings reason.
• 32:02
  SPEAKER_02: So this makes the trade-offs that I was mentioning before even more complicated.
• 32:07
  SPEAKER_02: What would happen in the future?
• 32:09
  SPEAKER_02: Are we gonna have windows that are improving or let's say uh designed only for increasing to the most the energy performance, the environmental performance of buildings, or also to have healthy indoor environments?
• 32:24
  SPEAKER_02: Is that possible at all to have a trade-off among those?
• 32:28
  SPEAKER_02: Or is maybe it's better that we just go outside, that we change our societal schedule, which looks a little bit complicated, but you know, sometimes I wonder, I never thought about that because I'm an engineer, so I have a problem, I try to solve the problem.
• 32:40
  SPEAKER_02: But sometimes it's yeah, yeah.
• 32:46
  SPEAKER_02: Wouldn't be that just easy to to give us like three, four hours of outdoor activities.
• 32:50
  SPEAKER_02: I don't know.
• 32:51
  SPEAKER_02: I'm just saying that I'm just just provoking.
• 32:54
  SPEAKER_02: But um, I don't know, these these these things are uh coming up and these I mean things are getting complicated.
• 33:00
  SPEAKER_03: These are major, major, major things, you know.
• 33:02
  SPEAKER_03: You're talking about the health of populations and again back to the UAE, like actually going outside is not practicable.
• 33:12
  SPEAKER_03: The investment going into Dubai and Abu Dhabi is is enormous, you know.
• 33:16
  SPEAKER_03: So you've got more and more people going there.
• 33:19
  SPEAKER_03: So one one feels that that sort of health aspect of kind of what people can access through windows.
• 33:26
  SPEAKER_03: I mean, it's it's they're gonna be really interested in it, I I imagine.
• 33:30
  SPEAKER_03: But I think what's really for me is kind of amazing is that very few people have sat down and thought this stuff through.
• 33:37
  SPEAKER_03: So, as you say, because you know, we've we've spent all of our time thinking about that kind of visible side of things.
• 33:44
  SPEAKER_03: And but by the way, I I think I'm gonna be talking to someone from UCL who's talking about the actual physiology of our relationship with with light.
• 33:54
  SPEAKER_03: So I'm very excited about that because it sort of feels like there's all these bits of a puzzle being kind of put together.
• 34:02
  SPEAKER_02: I think I might know where this person is and he's brilliant.
• 34:05
  SPEAKER_02: So it would be a much more interesting podcast.
• 34:07
  SPEAKER_02: I'm sorry.
• 34:08
  SPEAKER_03: No, no, no, my goodness.
• 34:10
  SPEAKER_03: This is a brilliant I mean, honestly, I've I've sort of I'm learning so much in terms of the way you think about you, you know, because I guess between you and Agar and a few others, you're at the kind of cutting edge of research around this very, very important subject.
• 34:28
  SPEAKER_02: I would I would say that thanks for the nice words, but I I would say that what is difficult and that's I think we are doing pretty good is to put different pieces of information that are not necessarily I would say extremely complex information, but there are very few people that actually put them together.
• 34:46
  SPEAKER_02: Uh and our field is actually pretty small, I must say.
• 34:49
  SPEAKER_02: We know each other pretty well in our smaller daylight research field.
• 34:53
  SPEAKER_02: Now, for example, this trade-off about environmental requirements and daylight requirements.
• 34:57
  SPEAKER_02: We just presented a master thesis.
• 35:00
  SPEAKER_02: So the two students I presented two weeks ago, I can mention them, Pauline, Karsten's, Luca Focus, they are called, from our master in energy efficient and environmental building design.
• 35:10
  SPEAKER_02: And so they were showing if there is alignment between the environmental and daylight regulation in Denmark.
• 35:18
  SPEAKER_02: So it was a very specific case.
• 35:20
  SPEAKER_02: And they were looking at renovation of buildings where it's a little bit easier to get the environmental performance through.
• 35:27
  SPEAKER_02: And they were showing that it's quite interesting.
• 35:29
  SPEAKER_02: If you really want to apply both the environmental, existing environmental regulation in Denmark and the existing daylight regulation, most likely you almost don't find any solution.
• 35:41
  SPEAKER_02: So you cannot comply with both regulations at the same time.
• 35:44
  SPEAKER_02: Because those two and those two, let's say, entities or like expertise, they seldomly speak, and it's very hard to see the interdependence among things, even in the built environment, and you end up in this uh a little bit absurd situation in which you have a regulation that contradicts itself, uh, I would say.
• 36:06
  SPEAKER_03: I mean, again, it's amazing, but I think it's sort of uncovering these insights, which is the key to kind of sorting things out a bit more in the future, isn't it?
• 36:14
  SPEAKER_02: Yeah, yeah, absolutely.
• 36:15
  SPEAKER_03: Well, listen, it's been really, really interesting talking to you both.
• 36:19
  SPEAKER_03: I mean, I I can't wait to see the see the um the the the results of your survey, Agar.
• 36:25
  SPEAKER_03: And if there's uh any way we can kind of get access to some of these papers, we would be really kind of pleased to do that.
• 36:32
  SPEAKER_03: And Agar, if you can send me a link, I can post it on when we sort of publish this podcast, we can include the link to the survey as well.
• 36:41
  SPEAKER_01: Great.
• 36:41
  SPEAKER_01: Thank you, Dave.
• 36:42
  SPEAKER_01: And yes, we we publish everything with open access here in Sweden, so you can just search our names and uh you will find out what we do.
• 36:50
  SPEAKER_03: Amazing.
• 36:51
  SPEAKER_03: Well, listen, I really appreciate you both coming on and spending the time talking to me about this amazing.
• 36:57
  SPEAKER_01: Thanks for having us.
• 36:59
  SPEAKER_02: Thank you, Dave.
• 37:00
  SPEAKER_02: It was fantastic, and uh it was great to speak to you and we enjoy your podcast and we will keep listening to it.
• 37:08
  SPEAKER_03: Yes, fabulous, fabulous.
• 37:11
  SPEAKER_02: Thank you.
• 37:11
  SPEAKER_02: Bye bye.