In this project, we used wood and brick siding to not only promote green building, but to also reduce the thermal mass of the house, to cool the temperature of the home.
Don’t you love the look of Austin stone on a home? Many neighborhoods in Bryan and College Station require a high percentage of brick or other masonry products on the exterior of their homes. It is a great look but not a great approach, especially if you are interested in green building or even just reducing your utility bills.
Brick and other masonry products are known as thermal mass. Thermal mass is the ability of a material to absorb and store heat, in this case, your siding material’s ability to absorb that heat. In other words brick heats up all day and disseminates that heat to the house.
But, you may be wondering, what about adobe? Adobe is used in hot dry climates, not hot humid climates. The difference is that in a dry climate, temperatures cool down at night. The heat absorbed by the adobe does not make it into the house before it is cooled by the night air. Water in the air also serves as somewhat of a thermal mass, holding heat longer than dry air, which is what keeps or night time temperatures higher than in the desert.
The vernacular architecture of hot humid climates usually feature siding for a reason. But, if you are stuck with neighborhood controls requiring a high percentage of masonry or if you just like the look of stone, there are some things that you can do mitigate the negative impact of a thermal mass.
Perhaps the most effective thing to do is use a veneer stone which is much thinner than traditional stone. Also try to avoid masonry on the west side which tends to get more direct sunlight at the hottest part of the day. Want to learn more about siding that we recommend. For even greater shading use larger than normal overhangs where possible.
As always, use landscaping as a design element for beauty and function. Deciduous trees on the west provide crucial summer shading while allowing the sun through in the winter.
Brick can also create moisture and potentially rot problems if a proper drainage pan is not created behind it. Of course any cladding can become a problem without proper moisture sealing. This is an area that you should question a builder about before hiring. There are no requirements in Texas for builders to have knowledge of building science and this is a place that lesser builders tend to get themselves into trouble.
This is a visual of the effect thermal mass has on your home.
Here in College Station and Bryan we have a very hot and humid climate, which presents a unique set of design and construction challenges. For one, traditional approaches to thermal mass walls are out for us. However, this potentially beautiful design approach is not necessarily a bad idea; if we modify its application from what is traditional.
Thermal mass is thick, highly dense material. This category includes stone, adobe, and brick. The idea is that through the hot day, heat does not penetrate the full depth of the thermal mass. Then, at night the outside temperature cools down enough to pull the heat out of the wall so that the process can start over the next day. Yet, because our humidity is high, we do not cool down enough at night to pull the heat out of the wall. Consequently, over time the wall serves to heat the building.
It is odd that brick is the preferred veneer through most of the hot and humid gulf coast south. Even though this is not usually structural brick, there is an air space between the brick and the insulated wall. Nonetheless, the brick is a very affective solar collector that creates a hot surface next to the house.
On my own house that was built in 1950 and once had a 100% brick veneer, I removed all of the brick that was serving to heat my home. I replaced the brick with a second insulated wall and sided it with fiber cement siding. In doing this, I was able to more than double the insulation, create a better air seal and reduce the heat next to the house. I also happen to think that it looks a lot better.
Okay, so now that we understand the process of eliminating thermal mass, how can we use it to positively affect the Brazos Valley? As we pointed out, thermal mass works well in hot, dry climates that cool down at night. In a hot, humid climate we can bring the thermal mass inside, away from the source of heat; and have it work for us. When this is done, the mass assumes the ambient inside temperature. Consequently, as temperatures rise through the hot part of the day, it helps to reduce the cooling load required to keep the house comfortable. It does this by absorbing some of the heat in the air. Although the same amount of energy is needed throughout the day, there is less of a peak load required for the hottest part of the day; which allows us to reduce the size of equipment needed to keep the house cool.
Unfortunately, more research is needed to quantify this effect. Currently, there is nothing in the program that calculates equipment size that takes this into account. Good air conditioning companies are reluctant to deviate from the standard sizing of equipment. We love our AC mechanic and have a huge amount of trust in him. However, we frequently push him to reduce equipment size because we design in ways that reduce load but that are not considered in load calculations.
Next time I will talk about using interior thermal mass in home design.
It is our recommendation that you change AC filters once a month when you are leaving your system on all the time, so you will see this task on our list for most, but not all, months. Changing out the AC filters will extend the life of your system, allow it to operate more efficiently, and even help keep the house clean. That’s right – the filters collect dust that would otherwise be spread through the house. It is a good idea to buy a carton of filters at a time. Pay close attention to the direction arrows when installing each filter. We also recommend writing the date on the filters so that you will know at a glance when they were last changed.
I recently returned from the Greenbuild 2014 conference in New Orleans. This is an annual conference put on by the United States Green Building Committee (USGBC.) It is three days of intensive learning about a wide range of design and construction concepts that relate to creating a smarter and healthier built environment.
My favorite sessions this year had to do with Biophilia, which is the study of the positive effects of nature in our lives and ways to increase our exposure to nature in the built environment. The term and general concept has been around for many years, introduced by E. O. Wilson in his book by the same name. But it has only relatively recently been picked up by the design community.
This is a thrilling development for us at Stearns Design Build, as it is so similar to our own theory of design that we call Transitions. Transitions is built on the knowledge that connection to nature and natural rhythms creates happiness. We know, for example, that people who know what time the sun rises and sets, or what phase the moon is in, consistently report a higher level of happiness and contentment. So the question becomes: in the modern world of rather insular homes, how do we create these connections for people?
The most predominant feature on the modern American home is the cavernous garage, with doors that open mechanically, swallowing cars, saving drivers and passengers from interaction with neighbors that they do not know. The backyards of most homes are no less isolating. Surrounded by a tall privacy fence, maintaining protection form neighbors and natural surroundings. Most of the trees that the yard may have once had were taken down during construction and replaced with turf that requires weekly maintenance and large amounts of pesticides and herbicides.
At one time American homes had large front porches that provide a fresh air room with access to neighbors who were frequently out for a walk. Those porches have shrunk and, if they exist at all, are a façade feature too narrow to accommodate a chair.
Modern residential design creates homes that isolate us from both community and nature.
The Ancient Greek word for community was koinonia. But it was more often used as a verb rather than a noun. It also translated as share, participate jointly and intimacy. This is the word that got translated to “fellowship” in the New Testament of the Bible. For us, community has become a place or a group of people: a passive noun, not an active verb describing how we are in community.
The philosopher Martin Heidegger, in his book What Is Called Thinking, spoke about the separation of the self from nature in language and in thought. This separation is the source of modern angst. This angst belongs to us and to all of nature. When we do not view ourselves as a part of nature, it becomes easy to view nature only as expendable resource. Heidegger said, “Nature becomes a gigantic gasoline station, an energy source for modern technology and industry.” Angst manifest in nature as climate change, habitat destruction, smog and extinction.
Our Transitions theory of design seeks to assuage modern angst through the phenomenology of design. By placing us in the context of our surroundings, both natural and community, we can impact who we are and provide a sense of connection and transcendence in the world. This bold undertaking is the essence of humbling, as we must recognize that we are a part of, and not apart from, larger systems.
To the extent that we seek “green” or sustainable solutions, it is not enough to consider the resources that we use in building, we must consider our relationship to all resources. We must design homes that put us into relationship with life’s resources so that we can become aware of our part of a process of dynamic balance.
Which is the least expensive energy retrofit? A. Installing solar panels B. Replacing existing windows with high efficiency windows C. Installing energy star appliances D. Sealing air leaks
Which has the highest ROI? A. Installing solar panels B. Replacing existing windows with high efficiency windows C. Installing energy star appliances D. Sealing air leaks
You might enjoys this article for more information.