Special framing techniques, such as a continuous air barrier, reduce leaks and drafts. Framing is the foundation on which an energy efficient home is created.
Improved Thermal Systems
Enhanced insulation techniques with special attention paid to gaps, voids and compression to prevent the reduction and the effectiveness of the insulation. The insulation needs to be in physical contact with the air barrier, as a primary means of preventing air movement between conditioned and unconditioned space. Insulation products should be GREENGUARD Indoor Air Quality Certified® or manufactured from at least 75 percent recycled content.
Right – Sized HVAC
"Right-sizing" a home’s heating and cooling system is important because it contributes to the performance and efficiency of the equipment – and to the comfort of the occupants. When it comes to a tightly constructed, energy efficient home, bigger equipment is not necessarily better. Oversized HVAC equipment operates less efficiently and can cause humidity problems – in addition to being more costly.
Framing and Sheathing
Air barrier continuity must be maintained throughout the entire structure – including knee walls, soffits, garage interfaces and other areas of the home that may need special attention. Rigid exterior sheathings capable of stopping airflow are required at all levels. It is recommended that roof sheathings include a reflective barrier, except when insulation is applied to the underside of the roof deck. These framing and sheathing requirements work together to create a tight building envelope and ultimately an energy efficient home.
Lighting Efficiency – CFL/LED Lighting
At least 60 percent of all hard-wired lights need to be compact fluorescent lights (CFL) or light emitting diode (LED) lights, which reduce home energy consumption.
Optional Lighting Efficiency – Dimming
Use dimmer switches for non-fluorescent fixtures, which allow homeowners to reduce watt usage.
ENERGY STAR appliances
ENERGY STAR® - a program of the U.S. Environmental Protection Agency and the U.S. Department of Energy – promotes energy efficient products and practices. Appliances that qualify for ENERGY STAR designation meet strict guidelines set by the EPA and DOE. According to the EPA and DOE, ENERGY STAR qualified appliances incorporate advanced technologies that use 10 to 50 percent less energy and water than standard models.
Toilets should meet the U.S. Environmental Protection Agency’s (EPA) WaterSense™ specifications for efficiency and performance. This includes an effective flush volume of 1.28 gallons, which is 20 percent less than the federal standard, and solid waste removal of 350 grams or greater. According to the EPA, WaterSense™ labeled toilets combine high efficiency with high performance and save water without a trade off in flushing power.
High- Performance Appliances
Clothes washers should be ENERGY STAR® qualified and have a water factor (WF) no greater than 6.0. Water Factor is a measure of water efficiency, calculated as gallons of water used per cubic foot of capacity. In other words, the lower the water factor, the more energy efficient the clothes washer. According to the information from ENERGY STAR®, high performance clothes washers that meet use an average of 55 percent less water than standard models and about 31 percent less energy to run the washer and heat the water.
Engineered Plumbing Systems
In order to reduce water wasted during the time it takes hot water to reach the tap, it is recommended that builders follow one of several options for efficient plumbing design. These range from central location of the water heater to a demand-controlled hot water recirculation pump. Efficient plumbing design helps to reduce the “wait time” for hot water – thereby conserving water – and also helps reduce the amount of energy used to heat the water.
Indoor Environmental Quality
Duct connections should be sealed with a UL-listed mastic product, and all supply and return boot-to-house connections are sealed with UL-listed class 1 pliable sealant such as mastic or caulk. This technique, combined with specific duct tightness, helps keep attic dust and other contaminants out of the home’s ventilation system.
“Right-sizing” a home’s heating and cooling system not only contributes to the efficiency of the equipment – it also helps to manage indoor relative humidity by removing moisture during the cooling season. When systems are over-sized, moisture problems can adversely impact indoor environmental quality, along with affecting occupant comfort.
Avoiding the build-up of carbon monoxide (CO) is important for occupant safety. Utilize hardwired and removable CO detectors in all homes.
Fresh Air and Spot Ventilation
Utilize mechanical fresh air ventilation throughout the home, in addition to spot ventilation in the kitchen and bathrooms. Fresh air ventilation means that filtered outside air is brought into the home through the HVAC system. We recommend a high performance filter or approved electronic air cleaner. Spot ventilation in kitchens and bathrooms is important because it helps move moisture from showering and cooking out of the home. The kitchen and bathroom ventilation must be capable of exhausting to the outside a specific volume of air at a specific rate.
Air Pressure Balancing
All rooms (except bath and laundry rooms) in the conditioned space should not exceed a pressure differential of +/- 3 pascals with respect to the outside when interior doors are closed and the air handler is operating. Returns, transfer grills, or jump ducts may be needed to balance each room.
Internal Moisture Manager
Moisture – whether it’s naturally occurring from condensation or created by occupant activities such as cooking and showering – is important to manage for the purpose of indoor environmental quality. Builders must follow the Energy and Environmental Building Association™ (EEBA) Water Management Guide so that moisture entering building assemblies has a way to dry – either to the interior, exterior or both. Tub and shower surrounds must be backed with specific water resistant materials. And, in hot, humid climates, additional requirements apply, such as not using vinyl wallpaper in kitchens and bathrooms.
Paints must contain low levels of VOCs – volatile organic compounds. VOCs are organic substances that can off-gas from solid of liquids, including paint and coatings. By using low-VOC products, exposure to these compounds is reduced, resulting in better indoor air quality in the home.
Carpet products should carry the Carpet Rug and Institute (CRI) Green Label® for low-VOC (volatile organic compound) emissions. This results in better indoor environmental quality because it limits substances that can off-gas. In addition, low-VOC tack strips and adhesives are required for carpet installation. Do not use urea formaldehyde wood products under carpets. Use a central vacuum in homes where carpeting exceeds 70 percent of the floor area in conditioned space.
Optional Acoustical Package
Indoor environmental quality isn’t just about air quality – it also includes attributes such as sound that contribute to the comfort of the home’s occupants. Builders can install an acoustical package, intended to result in a sound transmission coefficient performance of 37 to 39. In a word, quiet.
Optional Advanced IEQ System
With so many consumers increasingly concerned about indoor environmental quality, builders and homebuyers may want to consider adding an advanced IEQ system to provide an even greater range of benefits. Builders may choose to offer an advanced IEQ equipment package, which is based on four pillars of improving indoor air quality – source elimination, ventilation, cleaning/ purification, and monitoring. Equipment for this option includes a purification system, advanced HEPA filtration, germicidal lamp and other components that vary according to climate.
Optional Framing – Optimum Value Engineering
Builders are encouraged to apply Optimum Value Engineering (OVE) techniques, also known as advanced framing, in order to reduce lumber requirements while maintaining structural integrity.
The air barrier inhibits air from entering and exiting the building envelope, and plays an important role not only in energy efficiency but also in durability – because it is part of the system that controls the air, heat and moisture flows. At all levels, a continuous air barrier and sealing of penetrations is required. Components and finished surface materials such as drywall and sheathing act as barriers, but regardless of the material, it’s important that the air barrier is continuous and that the holes are sealed.
Three primary physical forces adversely affect the durability of building materials – air, heat, and moisture – and the physics of how they impact durability often interrelate. The air barrier, thermal barrier, and moisture barrier work together as a system to manage air flow, heat flow, and moisture flow. The thermal barrier or insulation is to be applied in direct physical contact with the continuous air barrier, in order to minimize air flow that can reduce the effectiveness of the insulation. Fiberglass, cellulose and foam insulation materials are all effective thermal barriers, but regardless of the material, it’s important that the thermal barrier is in physical contact with the air barrier.
Internal Moisture Management
Moisture is one of the three primary physical forces that can adversely affect the durability of building materials – with air and heat being the other two. Whether it’s naturally occurring from condensation or created by occupant activities such as cooking and showering it is important to control moisture. Builders must follow the Energy and Environmental Building assemblies has a way to dry – either to the interior, exterior or both. Tub and shower surrounds must be backed with specific water resistant materials. And, in hot, humid climates, additional requirements apply, such as not using vinyl wallpaper in kitchens and bathrooms.