We use the term building science a lot. For those who may have never heard the term, or fully explored it, here is a quick debrief.
Taking into account experiences of architects, engineers, and builders, building science explores the way that a building responds over time to environmental factors and natural phenomena. Or, a detailed study of a building with the goal of increasing its life span, health, and/or performance, and applying those lessons to new buildings.
Indoor Air Quality/Indoor Environmental Quality
This covers things like sound/acoustics, lighting, indoor air pollutants and how to control them. Ever heard of “sick building syndrome”? In those cases, actually being inside a building will negatively affect a person’s health, whether from stale or toxic air, lack of good ventilation, noise levels, or a number of other factors.
Air conditioning, heating, and ventilation are some of the important mechanical systems. Without proper systems, filtration, and flow, a building will not function well and keep its inhabitants comfortable. We prefer balanced ventilation, like an energy recovery ventilation system that is continuously alternating between bringing fresh air in and venting stale air out, while maintaining the temperature indoors to prevent energy loss.
ENCLOSURES and Air/Moisture Barriers
An enclosure is simply the surfaces of a building that separate indoors and outdoors. Walls, ceilings, windows, and soffits. Not surprisingly, better methods for keeping moisture out of building materials will prolong their life and reduce problems like mold and rot. So, things like air and vapor barriers are very important. They also increase the energy efficiency of buildings, and reduce operating costs from heating and cooling. However, its all connected. Since a home with a “tight envelope” or a continuous air or moisture barrier doesn’t allow air to flow through cracks, it will also need to be closely monitored and have a good, balanced ventilation system in place to circulate fresh air and reduce indoor air pollutants.
With the increasing awareness of the pressures that humans are placing on the global environment, we recognize the role that the construction industry needs to take on in reducing our impact. Big changes can be made with a choice of materials that have a low carbon footprint, or by building using carbon rich materials like wood, hemp, and straw that sequester the carbon out of the atmosphere. Things like passive solar design and an integrated landscape and water management plan also help to greatly reduce a building’s need for external energy inputs.
Modern Building Science, Traditional Materials
Hopefully it’s all coming together for you. At Living Craft, we are always trying to educate ourselves on the latest innovations in building science. We are doing the work of researching and picking out the best solutions which honor the traditions of building and respect the environment on all levels. If you have questions, we would love to hear them!
In the sunny Front Range of Colorado, we see solar panels on a daily basis. But harnessing the power of the sun for your home is not limited to this high tech solution. People have used the sun in myriad ways in the past, and we can continue to make use of low tech, design focused options for capturing and using the sun’s free power.
Passive Solar Design
Passive solar design is a set of design tools that can be used in any part of the world to create a home that is warm in the winter and cool in the summer while using a minimal amount of energy for either cooling or heating. This means less petroleum products, wood, or other bio-fuels, which in turn means less CO2 emissions and other pollutants that are released in the burning of fuels. Burning of fuel or use of electricity also equates to direct financial burdens on those who use them, so using passive solar design can keep more of your money in your wallet.
Passive vs. Active
You might wonder how passive solar design got its name. Active solar generally refers to systems that require extra items that are attached to a building and are not already integrated into the home’s structural needs. These include solar collectors, solar panels, or rooftop systems for heating water. They often need pumps, timers, sensors, and/or wiring to get and keep them working. Passive solar doesn’t require these extras, but is able to be achieved using only the same materials that you would need to build any house, just rearranged into a design to maximize your ability to gather energy from the sun. Therefore, there is usually no added expense!
Principles of Passive Solar
Know your Location
Passive solar design works with the patterns of nature. The sun’s relative position in the sky is influenced both by the location that you live in and what time of year it is. Ideally, a builder or homeowner would have time to observe the site all year round to notice where the sun rises and sets each time of year, where winds come from, and any natural features that may provide shade, windbreaks, or create microclimates. Obviously, this isn’t always possible, but if you know your latitude, you can at least begin to calculate the angles that the sun will hit the house during different times of year. That being said, there are a variety of apps available for smart phones and online tools that make doing these calculations fast and easy.
Site to the South
Ideally, a passive home in the northern hemisphere should be sited on a south facing slope or in a location that gets plenty of southern sun. Most of the windows and entrances should be located on that side, to allow sunlight into the home where it can create heat. This means that the longest axis of the house will run east to west. Minimizing openings on your North face is important to prevent heat loss.
Don’t forget Outside Spaces
In addition to siting your home facing south, remember that outdoor spaces are best enjoyed with the sun, too. If your home shades your yard, consider moving it so that there’s more usable yard space on the sunny side for things like gardens, patio space, and hammock swinging. Planting deciduous trees on the West face of your home will minimize heat gain during the hot summer months.
Store up Heat
The heat that you are allowing in from the sun will need to be stored using thermal mass. Thermal mass can be any material that holds heat well. Water is one of the best materials for this, but not very practical for inside a home. As natural builders we often use earthen and lime plasters, as well as an earthen floor as our form of thermal mass. Interior adobe or cob walls that get direct wintertime sun are also a great heat sink.
Keep Heat in
Once you’ve got all the sun’s energy stored in your home, you need to keep it in. Use highly insulated walls and ceilings (we recommend natural insulation systems such as straw bale or hempcrete walls and cellulose for ceilings). Make sure there aren’t leaky areas in your home, around windows or doors. Even with a great insulation system, a drafty home will keep you chilly in the winter. Plasters create a monolithic wall coating that are an excellent air barrier.
Not too many Windows…
So if south facing windows are good, maybe a whole south facing wall of glass would be better? Not so, usually! Over-glazing can result in too-hot-homes, any time of year. Also, windows will never be as insulative as walls, so you risk having all the heat escape at night.
Also the Right Windows…
Windows that work, and work for your home, are great! Modern windows have so many features to look for and some will do better on different sides of your house (more to come on that topic!). Vertical windows on the south wall are better for letting in the low, more direct winter sun, and reflecting away higher-angle summer sun.
Cool Down Sometimes
You might think a passive solar house will get too hot in the summer. Opening windows and designing so your house can catch cross breezes is one way to help. So is something as simple as blinds or insulating curtains. Designing wide overhangs on a house can keep the high summer sun out of south facing windows. You can also plant (or keep existing) deciduous trees and shrubs on the south, east, and west sides of the house. That way, your windows will be shaded from summer sun.
Breathe Fresh Air
A house needs to have fresh air coming in. Particularly in modern well-insulated and air sealed homes, indoor pollutants can create unhealthy air conditions! A ventilation system is helpful, or necessary, to keep the home healthy. Using natural materials in and on your walls (straw or hemp insulation and plasters or clay paints) and floors (like earth, tile, or naturally finished wood) is another way to keep air clean by not introducing strange chemicals.
Keep Backup Systems Small
One great part of having a passive solar designed home is that your heating and cooling systems can be minimized, another immediate cost saver.
This isn’t the Passive Solar of the 1970s…
People might worry that their passive solar house is going to be the odd one on the block. Not so! Any style of architecture can be adapted to passive solar principles.