Energy – Frequently Asked Questions
Q: Why is it important to consider the house as a system? Click to expand
A: Each change in construction methods and every new building product effects the whole house. Careful evaluation is critical to avoid negative results, such as adding insulation, which can unintentionally increase moisture accumulation, leading to increased mold growth and structural assembly rot. All because little consideration was given to the house as a system.
Q: What does energy efficiency or sustainable building mean? Click to expand
A: For us, sustainable building means requiring fewer nonrenewable resources to operate and is healthier to live in. Despite the trendiness of alternative building materials, the most intelligent thing any of us can do when building or remodeling is to reduce our homes’ reliance on energy (water, gas or electric) and improve its indoor air quality.
Q: Doesn’t it cost a lot of money to go energy efficient? Is there a return on investment? Click to expand
A: Not only is going energy efficient affordable, but the financial and health benefits far outweigh the initial costs. We estimate that it costs from one to two percent more (excluding tax credits) upfront to build a home that uses up to 30-40% less energy than conventional construction. In fact, the typical payback period is less than four years. And not only will you enjoy the continued savings, but your home will be worth more. In addition, improving the tightness of your home and ventilating properly can result in a healthier environment for you and your family.
Q: Are there builder and homeowner tax credits available? Click to expand
A: Yes. Both builders and homeowners can take advantage of tax credits and discounted utility bills when they build a home that uses less energy. Check out www.energystar.gov for more details.
Q: What is the “stack effect” and how do I prevent it? Click to expand
A: Stack effect is the movement of air into and out of buildings and is driven by the difference in buoyancy of warm and cool air. The greater the thermal difference and the height of the structure, the greater the buoyancy force and thus the stack effect.
Q: Why is it important to build a “tight” house? Click to expand
A: A tight home means your home will be free from unwanted moisture, pollutants and other contaminants that may affect the health of the structure, its occupants and its value. Building tight also means a more comfortable home. Temperatures throughout the home are more consistent.
Q: Can a house be “too tight”? Click to expand
A: The simple is answer is no. As long as you provide proper ventilation.
Q: Should a house be allowed to breathe? Click to expand
A: Yes, houses should breathe. But only through designed holes. These holes come in all shapes, sizes and designs. Your house should ventilate, but not infiltrate. Ventilation is the intentional movement of air from the outside to the inside of a building. When people or animals are present in buildings, ventilation air is necessary to dilute odors and limit the concentration of carbon dioxide and airborne pollutants such as respirable suspended particles (RSPs) and volatile organic compounds (VOCs). Infiltration is the unintentional or accidental introduction of outside air into a building, typically through cracks in the building envelope. Normally, infiltration is minimized to reduce dust, increase thermal comfort and decrease energy consumption. In typical modern U.S. home, about one-third of the HVAC energy consumption is due to infiltration. As such, reducing infiltration can yield significant energy savings, with rapid payback.
Q: What is a sealed or closed crawl space? Click to expand
A: Closed or sealed crawl spaces have no vents and are properly sealed to the outside. A vapor retarder is used to cover the ground and walls. Insulation should be used in either the sub-floor or on the crawl space walls.
Q: What are the costs associated with a closed crawl space? Click to expand
A: Costs vary for new or existing homes. For new homes, there is very little additional cost between a vented and closed crawl space. With changes to the new building code, the only thing that separates a closed from vented crawl space is the liner on the walls and the absence of vents. Whether you are doing a closed or vented crawl space, new code requires a minimum, 6 mil, over-lapped vapor retarder on the ground and the installation of insulation in either the sub-floor or on the interior of the crawl space wall. Variables associated with cost include the current condition of the space, existing insulation, presence of mold or wood rot, water problems, combustion appliances and air sealing. All things considered, the benefits associated with a closed crawl space by far outweigh the costs.
Q: What are the primary differences between a closed and vented crawl space? Click to expand
A: There is one simple difference between a vented and closed crawl space. A closed crawl space is designed to restrict the free flow of unconditioned air through the crawl space. A vented crawl space is designed to do the exact opposite.
Q: What are the financial and other benefits of closing my crawl space? Click to expand
A: The first benefit is a 15-18% reduction in energy usage. The second is moisture control and the avoidance of expense associated with mold and wood rot. Despite these financial benefits, the primary reason for closing a crawl space is to improve the health of the building and its occupants.
Q: Is it better to insulate the sub-floor or the crawl space walls? Click to expand
A: As long as the insulation is installed properly, either one of these options is fine. In new construction we typically insulate the walls and seal the sub-floor.
Q: Can you convert an existing, vented crawl space into a closed crawl space? Click to expand
A: Yes, in most cases. There are several factors that need to be considered, including venting combustibles, ductwork and design, water management and crawl space access, but these can generally be addressed with a site visit.