Week 6 Questions


Designing for improved IAQ is an excellent way in which to achieve energy savings.  Under the new ASHRAE IAQ guide, one of the major points is commissioning, which is essential to maintaining energy savings once a building is occupied.  Another point is the consideration of IAQ in the early design process, which leads to decisions that also directly impact energy use such as building orientation and HVAC systems.

One of the most intriguing ways in which energy savings can be achieved through IAQ is the use of Personal Comfort Systems (PCS), which are being developed by the University of California Berkeley's Center for the Built Environment (CBE).  The PCS will save a great deal of energy, primarily from reduced dependence upon HVAC systems, by allowing building occupants to control their personal space through foot warmers, heaters and coolers within chairs, and personal fans.  These systems use approximately 2 watts for cooling and 40 watts for heating, in comparison to traditional 1,500 watt space heaters.  The CBE has estimated that electricity use for HVAC will be cut by 30% through the use of these systems, and that natural gas use for HVAC would be reduced by as much as 39%.



There are a number of issues that lead to poor IAQ, many of which are addressed in the new ASHRAE guide for IAQ.  First and foremost is the lack of consideration for IAQ in the design process, which can lead to building orientation that is not ideal, and less efficient HVAC and ventilation systems.  This can be resolved by implementing an integrated design process in which the ways that systems interface with each other can be aligned for maximum efficiency and the best IAQ.

Another major issue is commissioning.  A lack of commissioning can allow poor installation of ventilation systems to go unnoticed.  To resolve this, commissioning needs to be done on a regular basis.

Moisture in building assemblies and ventilation systems is a serious concern for IAQ.  Roof leaks, rain penetration, inefficient envelope design, and inadequate filtration in ventilation systems can easily result in mold issues and biological growths that are extremely difficult to resolve without doing major work and renovation.  The way to avoid this is ensuring proper installation and maintenance of these systems, as well as thoughtful detailing during the design phase.



The benefits of daylighting indubitably extend beyond valuable energy savings.  As valuable as these financial savings are in and of themselves, the benefits for building occupants and the subsequent production and efficiency improvements are even more valuable.

Looking beyond energy, the psychological and physiological impacts of daylight are extensive.  With natural light, occupants not only feel better, but are physically better off as well because artificial light does not encompass as wide a spectrum as daylight.

The physical aspects of daylight lead directly to the psychological benefits.  Artificial light, which lacks the blue portion of the color spectrum, can be compared to a dark and cloudy day, which also prohibits people from experiencing the full spectrum.  On such days, many people will feel less energetic and not as happy as they generally are.  Occupants in a building with strong daylight feel much the opposite: less tired, in a better mood, and having a higher morale.

Daylight also affects hormones within the body, because the light absorbed by the eye alters melatonin levels that directly affect one's mood and ability to sleep, as well as body temperature.  If melatonin levels become too high, and body temperatures rise, this can have a domino effect upon the use of mechanical systems in a building such as HVAC.  High melatonin levels also make one drowsy, thereby negatively impacting production levels.

Abundant natural light has been shown to positively impact many different types of buildings.  Office buildings have reported higher productivity and increased office morale, as well as decreased use of sick time.  In schools with more daylight, students have achieved higher scores on tests and the health of the children has improved due to higher vitamin D intake and even fewer dental cavities.  Retail stores experience higher sales and longer visits from customers due to the more pleasant conditions and better color rendering obtained through natural light.  Another building type that has experienced major differences with increased daylight is hospitals.  Recovery rates improve, and staff and patients mutually benefit from the better moods that people are in.  The benefits for both building occupants and building owners are numerous, and certainly extend well beyond financial savings through decreased energy use.