Energy Efficient BuildingHouse as a SystemExperts in the residential construction industry have been researching energy efficient building and house performance for decades. The building sciences have determined that an individual component's performance is heavily dependent upon building the whole house as a system. If one component is weak, the overall system performance is less.For example, if there are gaps and voids in the insulation, the air conditioner or furnace will have to use more energy to meet thermostat requirements. If the house is well sealed but there is no fresh air ventilation, the home may become humid and air quality will suffer. This is a mistake that many well-intentioned builders make. CONTROLLED fresh air ventilation is critical to energy efficient building. InsulationA well insulated building envelope is an essential portion of the energy efficient home. That means insulation should be properly installed without gaps or voids. A gap in insulation results in convection ( hot or cold air moving through the wall cavity). If air movement is allowed, the walls temperature will rise or fall with that movement, eliminating the insulation value of the wall. Any void in insulation can cause inbalance in the house and will result in cold spots or hot spots in the home.Videos from Green Building TVWindowsThe owner builder should consider the type of windows that will be installed very carefully. Low-E (low emmissivity) windows reduce solar heat gain in the summertime. This can help lower the work load of the home's air conditioning system.It is important to also consider the heat transfer that occurs when using metal framed windows. If energy efficient building is the goal, vinyl windows are a better choice. Metal framed windows transfer heat from the outside. The same thing happens if steel studs are used for exterior walls. The right windows are a key component to an energy efficient building. Tight HouseA tight house is a well sealed house. This house does not allow UNCONTROLLED air infiltration. Air infiltration allows climatized air to escape and exterior air to come in and impact the interior temperature. The forced air unit will be working much harder to compensate. This additional work makes the home less energy efficient and leads to unecessary higher heating and cooling bills.
Fresh Air VentilationEnergy efficient building and the whole house system call for a tight house. To prevent the stagnation of air and accumulation of moisture inside, fresh air ventilation should be employed. Fresh air systems control the intake of fresh air and the removal of interior air.Blower Door TestingIt costs around $200.00 to schedule a blower door test. Ask the testing contractor if there is a combination price for both the blower door test and the duct blaster test. Find out what is included. Inquire if the test includes locating leaks and minor sealing.
Sealed DuctsMany homeowners do not realize that the performance of their forced air units is compromised. They have leaks in their ductwork or registers. It contributes greatly to the overall efficiency of the home to seal all ducts and registers. Registers can be sealed by applying mastic to all the seams. Sealing prevents air loss into the attic space or crawlspace.Duct Blaster Testing
Duct blaster testing will indicate how much leakage is present in the A/C ducts. The same contractor that does the blower door test will normally conduct the duct blaster test at the same time.
A blower is attached to the house ductwork and registers are sealed. The testing company has very sensitive instruments to measure air pressure and can determine how much air is lost into the attic via unsealed ducts. I had a unit that we continued to fail the test. Finally it was determined that the air was escaping at the edges of the register that attached to the testing gear. Insist on sealed ductwork and mastic sealing of all the registers in the house.
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