Below you will find all you need to know to turn your property into an energy efficient system. One Hour Heating & Air Conditioning is your Durham heating, AC, and insulation expert. Call us today at (919) 321-9985 to discuss your needs!
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- Energy Efficiency Services For Your Home Or Business
- Energy Efficient Tax Credits & Rebates
- Green Building Fact Sheets & Articles
Frequently Asked Questions:
- Why is it important to consider the house as a system?
- What does green or sustainable building mean?
- Doesn’t it cost a lot of money to go green? Is there a return on investment?
- Are there builder and homeowner tax credits available?
- Why is it important to build a “tight” house?
- Can a house be “too tight”?
- Should a house be allowed to breathe?
- What is a Manual J calculation and why is it important?
CLOSED CRAWL SPACE QUESTIONS
- What is a sealed or closed crawl space?
- What are the costs associated with a closed crawl space?
- What are the primary differences between a closed and vented crawl space?
- What are the financial and other benefits of closing my crawl space?
- Is it better to insulate the sub-floor or the crawl space walls?
- Can you convert an existing, vented crawl space into a closed crawl space?
SPRAY FOAM INSULATION
- What is spray foam insulation and how is it applied?
- Does spray foam cost more than traditional fiberglass insulation?
- What is the difference between open and closed cell foam?
- What are the differences between a vented and sealed attic?
- What is the “stack effect” and how do I prevent it?
WHY IS IT IMPORTANT TO CONSIDER THE HOUSE AS A SYSTEM?
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.
WHAT DOES GREEN OR SUSTAINABLE BUILDING MEAN?
For us, building green means requiring fewer non-renewable resources to operate and is healthier to live in. Despite the trendiness of alternative building materials, the greenest 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.
DOESN’T IT COST A LOT OF MONEY TO GO GREEN? IS THERE A RETURN ON INVESTMENT?
Not only is going green affordable, but the financial and health benefits far outweigh the initial costs. We estimate that it costs from two to four percent more (excluding tax credits) upfront to build a home that uses up to 60% less energy than conventional construction. In fact, the typical payback period is less than five 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.
ARE THERE BUILDER AND HOMEOWNER TAX CREDITS AVAILABLE?
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.
WHY IS IT IMPORTANT TO BUILD A “TIGHT” HOUSE?
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.
CAN A HOUSE BE “TOO TIGHT”?
The simple is answer is no. As long as you provide proper ventilation.
SHOULD A HOUSE BE ALLOWED TO BREATHE?
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.
WHAT IS A MANUAL J CALCULATION AND WHY IS IT IMPORTANT?
Manual J is the program designed by the ACCA that factors in size, design, location, materials, occupancy, etc. of a home in order to properly size the HVAC system. Without a Manual J, you risk the installation of an over- or undersized system, each with its own set of problems.
WHAT IS A SEALED OR CLOSED CRAWL SPACE?
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.
WHAT ARE THE COSTS ASSOCIATED WITH A CLOSED CRAWL SPACE?
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. But for existing homes, depending on the space, a typical closed crawl space retrofit costs between $2-$5/SF of crawl space. Variables 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.
WHAT ARE THE PRIMARY DIFFERENCES BETWEEN A CLOSED AND VENTED CRAWL SPACE?
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.
WHAT ARE THE FINANCIAL AND OTHER BENEFITS OF CLOSING MY CRAWL SPACE?
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.
IS IT BETTER TO INSULATE THE SUB-FLOOR OR THE CRAWL SPACE WALLS?
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.
CAN YOU CONVERT AN EXISTING, VENTED CRAWL SPACE INTO A CLOSED CRAWL SPACE?
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.
WHAT IS SPRAY FOAM INSULATION AND HOW IS IT APPLIED?
Spray polyurethane foam, commonly referred to as SPF, is a spray-applied insulating foam plastic that is installed as a liquid and then expands many times its original volume. SPF formulas can be tweaked to have many different physical properties depending on the use desired. For example, the same basic raw materials can make an insulation foam that is semi-rigid and soft to the touch, also create a high density roofing foam that is resistant to foot traffic and water.
DOES SPRAY FOAM COST MORE THAN TRADITIONAL FIBERGLASS INSULATION?
Yes, typically it costs two to three times the cost of traditional fiberglass batts. However, this costs is normally recovered within the first four years through energy savings. To learn more, visit our sprayfoam insulation page.
WHAT IS THE DIFFERENCE BETWEEN OPEN AND CLOSED CELL FOAM?
Open and closed cell are the terms used to differentiate between the two most common types of spray polyurethane foam. Open Cell is a low-density foam filled with tiny cells that are not completely closed. Air fills all the open space within the foam. When sprayed, it expands to up to 150 times the volume of its liquid state. Open Cell foam feels and looks like a sponge when it’s applied. It is an excellent insulator and sound proofing material. Open Cell typically has an R-value of 3.5. Closed Cell Foam is a medium density product that’s filled with tiny closed cells filled with gas that give the cells their size and density. Closed cell foam is generally rigid and it’s hydrophobic (repels water). It is an excellent insulator; as well as, an excellent air, thermal and vapor barrier. Closed cell can also increase the structural integrity of your home. Closed Cell Foam has R-values ranging from R-6 to R-6.5.
WHAT ARE THE DIFFERENCES BETWEEN A VENTED AND SEALED ATTIC?
A traditional, vented attic was designed to allow condensation to escape by allowing moisture to escape through gable vents by airflow. A sealed attic is an attic system that eliminates the need for gable vents by insulating the underside of a roof deck with air-impermeable insulation that doesn’t allow for condensation to develop. A properly sealed attic can be your best defense against high-energy bills, and it may be your only defense against the stack effect, and an HVAC system that can’t keep your house cool in the summer.
WHAT IS THE “STACK EFFECT” AND HOW DO I PREVENT IT?
Stack effect is the movement of air into and out of buildings and is driven by buoyancy. The greater the thermal difference and the height of the structure, the greater the buoyancy force and thus the stack effect. The stack effect is also referred to as the “chimney effect.” For our purposes, we use the term to describe the affect of a super-heated attic over conditioned space. This condition creates a pressure differential that can suck the cool air out of the conditioned space and up into the attic.
WHERE DO YOU STORE THE WATER?
Water is typically stored in prefabricated above or below ground storage tanks.
WHAT CAN I DO WITH THE WATER?
There are systems available allowing the water to be used in any application; however, the most typical uses are for irrigation or for use in the toilets.
WHAT HAPPENS IF IT DOESN’T RAIN?
A properly installed rainwater harvesting system has a supply input from a well or city water system that supplements the supply during dry periods.