| For many, a building is nothing more than four walls, a floor and a roof that contains the everyday items they need, use or enjoy. For others, including energy efficiency pros and building performance contractors, they take a more scientific view of those same structures. Building scientists realize there are many forces at work on a building (rain, wind, weight loads, mechanical systems, occupants, etc…) and maintaining a proper balance of each component, and the building as a whole, helps ensure the optimum building performance. From the simple task of sealing air or duct leaks, to adding more insulation, ventilation or even a radiant barrier, each change has an impact on how well your system works. These changes can either save you money and make you more comfortable, or decrease the durability of your home and the life cycles of it’s components. This scientific view is known as the “Whole-house” or “House-as-a-System” approach to building performance. Using specialized diagnostic tools, matched with a deep understanding of construction details, the building science “house-as-a-system” approach is the best way to optimize a building’s performance. This approach will provide the occupants with a comfortable, healthy and energy efficient environment to continue to enjoy for years to come.
To optimize your building’s performance you must be controlling: Controlling Moisture is vital to the buildings integrity, performance and health. Moisture is the leading cause of building degradation.
The basic ways that moisture is introduced is:
1. Bulk – liquid water (i.e. rain, plumbing leak, disconnected condensation line, etc…)
2. Vapor – moisture in the air (i.e. humidity, showers, talking, breathing, etc…)
3. Capillary – moisture wicking through building materials
Steam from showers or cooking, as well as occupants breathing and perspiration, all add large amounts of moisture to the home. Maintaining a healthy indoor air quality relies on controlling this moisture within the building. Spot ventilation in bathrooms and kitchens are one source of control, as well as whole house ventilation (ERV) and dehumidifiers. Many times, the right-sized AC unit alone can produce enough dehumidification throughout most of the year here in the lowcountry. Controlling the relative humidity in the home, not only protects it from mold and fungi growth, but also allows for a higher temperature set point which helps reduce your energy bills without sacrificing comfort.
Once you have identified moisture problems within your building, the quicker you respond and resolve the problem the better it is for your pocket and your health. Seven common signs of potential moisture “mis”management are:
* Musty, moldy smells, or the visual sign of mold, mildew and fungi
* Condensation on either side of the window (without rain)
* Paint that is peeling or chipping prior to its life cycle
* Cupping hardwood floors
* High humidity indoors (“sticky” or damp air), even when the AC is running a lot
* Allergies worse indoors than outdoors
* Water in the crawlspace
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Air flows freely, and as the air flows in and out of your building or home, it allows the free exchange of things you are trying to control – i.e. moisture, heat and allergens.
Many standard buildings allow for the free and uncontrolled movement of air within walls and between floors and ceilings, all which can contribute to many common problems. The uncontrolled airflow can deposit any of these elements anywhere within the structure, many times in places that are not easily detectable and often leading to mold or mildew, rot, and poor indoor air quality. Most insulations do not prevent air leakage, so unless the house is insulated with spray foam, controlling air flow should be a primary concern.
By focusing on the building envelope and eliminating these unwanted air leaks, greater control over the performance of the system can be realized. Stop paying for wasted energy that consumes your money and decreases your home’s performance. Conservation is good, control is great.
There are a couple of forces that effect air flow, or pressure, within your building. These are stack effect, wind, and mechanical ventilation (HVAC, ERV, Exhaust Fans).
Stack effect can be described like a chimney. As the warm air rises, it wants to push out of the hole at the top of the chimney toward the cooler sky; the same is true for your house, even on a one story house. The “chimney” in your house may be can lights, attic hatches, exhaust fans, etc… that you can see and identify, but it may also be hidden behind walls where finding the culprit is more difficult.
In the fireplace example, as air leaves the top of the chimney, replacement air is entering through the front of the fireplace, constantly feeding the fire with its needed air. The same cycle happens in your house as well. As the warm air leaves through the top levels of your house, new air is pulled in from the bottom of your building. Typically these holes are connected to conditioned spaces and have a negative affect on indoor air quality.
Although we cannot control the natural force of wind, designing or remodeling a building that is tight is the best approach keeping this force from stealing your comfort, health and energy dollars.
For the mechanical effect created from exhaust fans, HVAC, etc…ensuring they are balanced and operating properly helps prevent pressure differences that lead to air flow. For example, a commercial kitchen exhaust hood in your home should have controlled make-up air, or it will find its own through all the air gaps in your envelope. Pressure is always finding a balance, it is your responsibility to make sure you control how that equilibrium is maintained.
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Heat is transferred is 3 basic ways:
If you envision your building or home like a cooler, the concept of heat transfer becomes easier to understand. A cooler works well due to its air seal and insulation where it is controlling convection and conduction. An air-tight cardboard box with no insulation will not maintain, or contain, the temperature inside the box as effectively as a cooler due its poor design. There will be a significant transfer of heat from outside the cardboard box into the cold interior space due to its poor thermal resistance. This transfer, or balancing of temperatures, results in the ice melting, and you having a soggy box. If you added a see through window, on either the cooler or the box, this transfer process will be exacerbated from radiation. Controlling all types of heat transfer is crucial to optimizing your building or home.
When a building is built efficiently, it not only controls the air flow and moisture, but it also controls the rate at which heat moves through the building envelope. Contrary to what many believe, heat always moves from hot to cold, not just up and down. Here in the Lowcountry, heat is mostly trying to get into our houses throughout the year. The primary role of your insulation system, including the windows and doors (the home’s equivalent to a cooler’s lid), is to slow down this flow of heat. The better the insulation job, and the higher quality the windows and doors are in the building, the less energy you will need to maintain a healthy, durable and comfortable environment.
In the buildings that exist today, many do a poor job at controlling this heat flow. Some older ones have no insulation at all, and many more have inadequate amounts or poorly installed insulation at best. Some houses have inefficient single pane windows and even metal frames that are poor insulators, while others have newer double-pane windows that unfortunately don't have low-e coatings. Reducing solar heat gain reduces the amount of heat transfer through radiation, and is a sure way to improve the comfort and control of your home’s indoor environment.
Elm Energy Group will assess your building’s envelope and it’s effectiveness at controlling heat transfer, and make suggestions that optimize the comfort and efficiency of your building.
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An old and prevailing belief exists that your house has to breathe. With the advancements in building science and technology, it is now known that a building’s occupants need to breathe, not the building itself.
According to the EPA, the quality of our indoor air is commonly worse than the air outside; Nothing beats fresh air! Inside, we have many products that release VOC’s (off-gassing chemicals) into our indoor air (furniture fabrics, carpet, dry cleaning, wood finishes, paints, cleaning products, etc.), as well as pollutants such as pollen, dust mites, and pet dander that get indoors and need to be evacuated. A reliable introduction of fresh air must be maintained for the safety and health of the occupants inside buildings. Controlling how fresh air is introduced into your building is the key to controlling indoor air quality and the efficient use of energy.
Safety plays a part in controlling ventilation, but deserves a little more importance than a tag line. Commonly overlooked pollutants and health risks in the home are the byproducts of combustion appliances, especially carbon monoxide. Along with cars that are parked in an attached garage, a few examples of appliances that can introduce carbon monoxide into a home when incomplete combustion occurs are:
* gas stove tops
* gas fireplaces
* gas water heaters
Our certified building analysts will test your home to ensure the best indoor air quality exists, at the same time ensuring the safe operation of your combustion appliances. We follow the “Do No Harm” ethos. For more information visit the following link(s): Department of Energy - Energy Savers Website - Ventilation
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