Factsheet 2 - Natural Light / Daylighting

Overview

Daylighting refers to the application of natural light in an internal environment. Ensuring adequate levels of daylight reaches rooms in the dwelling can lead to energy savings by reducing the need for artificial light during the day. Beyond this, the liveability benefits of improved natural light in the home may include:

Physical and psychological health benefits
Economic savings due to reduced reliance on artificial lighting and reduced dwelling energy costs

Previous research has shown the beneficial social and psychological effects of building designs which feature natural light and views of natural surrounds, including reduction in stress, better emotional health, improved communication and a sense of belonging to a community or place [1] [2] [3] [4].

To reduce any potential negative impacts of daylighting, such as glare and heat retention, care must be taken to balance daylight penetration against solar heat gain wanted or otherwise. Knowledge of the sun’s path (sunrise to sunset) is essential for planning and assessing the effectiveness of daylighting strategies. Design should be flexible and adaptable to accommodate for different lighting desires. For example, optimising morning (eastern) sunlight is generally preferable to afternoon (western) sunlight, especially in kitchens and dining areas. Indirect light on the southern side of the dwelling, or filtered light on the northern side, is often preferred and may be important to those who work from home or who spend the majority of their time in the dwelling during the day.

“As humans we need fresh air and daylight when we are indoors. It has a positive effect on our health and wellbeing as well as our ability to learn.” [5]

Reduced reliance on artificial lighting can lead to energy savings. An MIT study revealed artificial lighting accounts for approximately 25‐40% of energy consumption in a typical building. [6]

What our findings revealed

Satisfaction with Natural Light
Balancing Wanted verses Unwanted Daylight
Natural Light and Feelings of Comfort
Balconies – Allowing Connection to Daylight

Satisfaction with natural light
Residents in the QUT High‐Density Liveability Study were generally satisfied with natural light in their dwelling. Only 13% of residents made modifications or adjustments to the outside of their dwelling (sunshades/external shading) and only 3% had enclosed balconies. Interviews with residents in inner‐city high density dwellings provided further insights into the importance of natural light, or daylighting, for reasons of aesthetics as well as thermal and lighting comfort.

Balancing wanted verses unwanted daylight
Residents recognised advantages of daylighting in their dwelling yet were also mindful of the negative impacts of heat from the sun, particularly at certain times of the day (e.g. afternoon) and times of year (e.g. summer).

Yes [natural light here is] good, the only real problem is that two months in summer time, for about a couple of hours in the afternoon, you get the western sun going over the TV towers there. It gets a bit hot but other than that, it’s perfect..

To achieve optimal daylight, many residents either wished they could change the dwelling to allow more light inside or worked within the constraints of their dwelling by using shades and blinds to manipulate and direct natural light. Residents were also very aware of the importance dwelling orientation played in daylight penetration.

It’s designed well for breezes but the lounge room, living area is on the west facing wall so one of the first things I did was put up block out blinds along that wall because we’d get really hot from the full sun.

It’s excellent. Because we get mainly southern light...[U]nfortunately we don’t get direct sunlight until the afternoon because the sun comes over this way.... So it would have been nice to get more sun maybe in the morning, but there’s not much we can do about that.

I’d like to poke a hole in the ceiling and let some light in but you don’t want to break the membrane up above otherwise if water gets in causes you grief and all sorts of structural things.

Natural light and feelings of comfort
Natural light was not only associated with sunlight and heating but also with a ‘feeling’ of more open space, therefore creating a more comfortable, liveable and aesthetically pleasing dwelling interior. Maximisation of natural light, as one resident indicated, can also be achieved by changing the internal colour and decor of the dwelling.

[I] changed the colour scheme) because before it was all chocolate and brown and it was just too dark. I needed the lights on during the day. We just changed it all to white and brightened it up. It’s made such a difference. Before it was depressing walking in and we had the lights on all day. I hated it. Whereas now we don’t need [lights on during the day].

Balconies – allowing connection to daylight
Maintaining a connection to the outdoor environment is an important need for high density residents. This could be achieved through open windows and balcony areas. Many interviewees identified the balcony and associated open space and views as their favourite design feature of the dwelling.

I: How’s the climate in summer and winter?
I think (my favourite design feature of this apartment is) the balcony and the glass windows because it’s private… (and) just the open space of it.

I think our apartment definitely gets enough sunlight as we are on the second floor with a balcony that opens up.

Recommended Guidelines

Designing for daylighting, by incorporating balconies and other outdoor light sources in the dwelling, can improve health and well‐being.

The following table presents practical suggestions for Residents, Building Managers, Designers and Developers in relation to daylighting and maximising natural light in the dwelling.

Further Information

Sustainable Homes Brisbane
http://www.sustainablehomebrisbane.com.au/DESIGN.htm

Skylight Industry Association
http://www.siai.com.au/

Your Home Technical Manual and Website
http://www.yourhome.gov.au/

Level – The Authority on Sustainable Buildings
http://www.level.org.nz/passive‐design/daylighting/

Cleaner Greener Buildings – Qld Government Legislation
http://www.climatechange.qld.gov.au/__data/assets/pdf_file/0003/25626/3_P-and-B_-_E1_web.pdf

References

Clearwater, Y.A. and R.G. Coss, Functional Aesthetics to Enhance Well-Being in Isolated and Confined Settings, in The Human Experience in Antarctica: Applications to Life in Space., A. Harrison, Y.A. Clearwater, and C. McKay, Editors. 1990, Springer-Verlag: New York.
Collins, B., et al., Second Level Post Occupancy Evaluation Analysis. Journal
of the Illuminating Engineering Society Summer, 1990. 21-44.
Heerwagen, J. and L. Zagreus, The Human Factors of Sustainable Building Design: Post Occupancy Evaluation of the Philip Merrill Environmental Center. 2005, US Department of Energy Building Technology Program. p. 1- 26.
Leaman, A. and B. Bordass, Assessing Building Performance in Use 4: The Probe Occupant Surveys and their Implications. Building Research and Information, 2001. 29(2): p. 129-143.
Active Housing Forum. [cited 5 June 2009]; Available from:
http://activehousing.net/.
Science Daily. [cited 5 June 2009]; Available from:
http://www.sciencedaily.com/releases/2006/11/061114194440.htm.