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Recommendations for High Performance Homes

Compiled by Eric Martin and David Hoak
November 10, 2005

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1.0 Energy Efficient Building Envelope
 
1.1 Recommendations on the following building envelope features can be provided on a home-by- home basis after additional review:
 

1.1a Wall, ceiling, and floor insulation levels
1.1b Window properties
1.1c Vented vs. unvented attics and crawlspaces
1.1d Building envelope airtightness

2.0 Energy Efficient HVAC System
 
2.1 HVAC systems should be subject to rigorous and detailed design on a home-by-home basis that considers building envelope properties. Analysis using ACCA Manual J and Manual D can be provided. The following recommendations should be considered during HVAC design:
 

2.1a Right sized 2-speed high SEER (15+) heat pump HVAC system with variable speed blower. A “right sized” system with a multi speed compressor assures that the unit has a sufficient cycle time to both provide desired comfort level and optimum dehumidification.
2.1b Airtight tested ducts w/ returns. This ensures a tight duct system that keeps conditioned air inside the home and unconditioned air out. For flex duct, reinforced foil faced flex is recommended. Keep ductwork within the conditioned space wherever possible.
2.1c Positive Pressure ventilation. Positive pressure in homes located in humid climates keeps unconditioned humid air from penetrating the home envelope, reducing the risk of condensation on the interior surface of exterior wall assemblies. This could be accomplished on an intermittent basis using a 4” duct run from outside the home to the HVAC air handler return. The outlet of the outside air duct should be placed as close to the a/c or dehumidifier coil as possible.
2.1d Zoned HVAC system – System zoning ensures that only the areas of the home calling for HVAC get conditioned air. This is especially important in multi-story homes where balanced air temperatures between the floors can be very hard to achieve. Pressure relief should be designed among zones to prevent return induced pressure imbalances.
2.1e Air Handler Unit (ahu) in conditioned space – Placing the air handler in conditioned space keeps any system leaks in conditioned space. In homes with an attached garage, the ahu can instead be located in the garage within a sealed enclosure using an exterior door for access. This brings the ahu in the conditioned space and also increases the amount of useable conditioned floor area. Enclosure should allow air exchange with the main body of the home.
2.1f Programmable thermostat.

3.0 Energy Efficient Water Heating
 
3.1 Solar water heater. Hot water production is often a home’s 2nd largest consumer of power next to the HVAC system. Installing a solar water heater can reduce overall home energy consumption by 15%. There are a variety of solar heating systems available. Of them, the most efficient are those that use a thermosiphon to provide hot water circulation between the tank and collector. Pumped circulation systems generally require more maintenance and require a significant amount of power to operate. If a pumped system is selected, it is recommended that the pump be solar powered. A batch system (integrated collector-storage) is another good option requiring very low maintenance. Another recommendation is to install solar ready mounts and plumbing for future solar installations
 
3.2 Tankless gas water heater. By eliminating the storage loses of a traditional electric water heater, tankless gas water heaters can operate more efficiently. Tankless gas water heaters also take less space from the homes floor plan.
 
3.3 Centrally locate hot water heater among hot water uses and/or install an energy efficient hot water distribution system that includes either a demand controlled circulation loop (series), or central manifold system (parallel). Insulate all hot water pipes with minimum R-4 insulation.
 
4.0 Energy Efficient Appliances
 
4.1 Energy Star â Refrigerator and Dishwasher.
 
4.2 Energy Star â Clothes Washer with Water Factor < 9.5.
 
4.3 Clothes Dryer with moisture sensor.
 
4.4 Self-cleaning or pilotless gas oven.
 
4.5 Halogen, solid disk, radiant, induction elements, or pilotless gas burners on cook tops.
 

5.0 Energy Efficient Lighting and Ceiling Fans

 
5.1 Light colored surfaces – interior and exterior
 
5.2 Maximize use of Energy Star â labeled fixtures or and/or use of compact fluorescent bulbs. With a wide variety of fluorescent bulbs and bulb bases readily available, these lights can replace almost any incandescent light on the market.
 
5.3 Closet switches with built in timers. Closet lighting loads are commonly unintentionally left ON for long periods of time. This is especially true in the case of children’s bedrooms. However, these lights generally are only needed for very short periods of time. A timer switch ensures that these loads are not left on accidentally.
 
5.4 Utilize single bulb fixtures in bathrooms.
 
5.5 For outdoor lighting, avoid incandescent/flood fixtures on manual switches. Instead choose fluorescent, solar, low-voltage, and/or daylight sensing/timer controls.
 
5.6 Consider Gossamer ceiling fans in each bedroom and major living area. Such fans provide energy savings by moving more air with less power.
 
6.0 Water Efficiency
 
6.1 Equip all showers with only one showerhead.
 
6.2 Avoid garbage disposal and opt for compost bin.
 
6.3 Dual flush toilets that allow for < 1.6 gal/flush.
 
6.4 High efficiency fixtures: lavatory fixtures and shower heads < 2 gallons/minute.
 
7.0 Indoor Air Quality
 
7.1 Carbon monoxide alarms in addition to smoke detectors near attached garages sleeping areas.
 
7.2 Whole house dehumidification. Though a right sized HVAC system goes a long way to ensure proper dehumidification, these systems do not run year round. In Florida there are several months during the year where no call for air conditioning is made. A whole house dehumidification system ensures balanced humidity levels throughout the year.
 
7.3 High quality HVAC air filters. Air filters typically used in residential HVAC systems do not provide a very high filtration level. The deeper pleated filters providing a MERV rating of 10 or greater are recommended. Ensure any added pressure drop across such filters is accounted for.
 
7.4 Energy Star â rated kitchen exhaust fans vented to the outside. This directs hot and humid air outside the house instead of recirculation of this air inside the house. Ensure rated flow is achieved by using appropriately sized ducting and avoiding long runs and sharp bends.
 
7.5 If the optional fireplace is installed, use a direct-vented type with a fresh air intake. Or use an electric fireplace. DO NOT use unvented gas fireplaces.
 
7.6 Avoid impermeable materials and objects on the inside of floors and exterior walls such as vinyl wallpaper, large mirrors, and vinyl flooring. Use of such surface coverings can also lead to moisture accumulation problems.
 
7.7 Low sone Energy Star â bath fans with timers or humidistats. These fans have efficient and quiet operation, while timed control prevents unnecessary fan operation.
 
7.8 No urea-formaldehyde particleboard exposed to the conditioned space. Either opt for alternatives such as wood, solid surfaces, or wire shelving, or seal/laminate any exposed areas.
 
7.9 Zero or Low volatile organic compound (VOC) containing paints, sealants, and adhesives.
 
7.10 Flooring choices: carpet with CRI green seal of approval (limit to < 50% of conditioned space), linoleum or cork tile/sheet with water based adhesive, tile, hard surface (wood, bamboo, etc) flooring mechanically fastened or with water based adhesive, laminate flooring with no urea-formaldehyde and glueless or water based glue installation, concrete (stamped, stained, etc.).
 
7.11 Central Vacuum system. Central vacuum systems direct vacuum exhaust to the outside preventing redistribution seen by conventional upright vacuum systems.
 
7.12 Keep porous grout lines that can harbor dirt and allergens no wider than 3/16”.
 
7.13 Install screens on all operable windows and doors to promote natural ventilation.
 
7.14 Design for detached garage or include an air barrier in between attached garage and living space (including shared attic space). Or install exhaust fan capable of exhausting garage air in 15 mins. Fan should have automatic timer linked to occupant sensor, light switch, or garage door opener.
 
7.15 Seal off ductwork after installation until finish set.
 
7.16 Select healthy insulation choices such as water sprayed foam, formaldehyde-free fiberglass, expanded polystyrene, or cotton.
 
7.17 Design a useable entry area – well defined area in garage or main entryway where shoes and outerwear can be removed and stored. Provide track off mat, bench for sitting, and closet nearby.
 
7.18 Provide only low dust collecting window coverings – no mini blinds.
 
8.0 Material Resource Efficiency
 
8.1 Drywall with pre/post consumer recycled content.
 
8.2 Material efficient framing consistent with wind load requirements
 
8.2a Space joists & studs greater than 16 inches oc
8.2b Size headers for actual loads
8.2c Design perimeter, roof pitch, and eave width to 24 inch module
8.2d Use ladder blocking/drywall clips
8.2e Use two-stud corners
 
8.3 Use building materials and products that have been extracted, harvested or recovered, and manufactured within 500 miles of plant.
 
8.4 Consider using wood that is certified by the Forest Stewardship Council (FSC) as originating from a sustainably managed forest wherever possible.
 
9.0 Durability
 
9.1 Minimum 2 ft overhangs on eaves, 1 ft on gable ends. Or install a gutter system that incorporates leaf/debris screens or filters. Such strategies help to keep rainwater away from walls and foundations.
 
9.2 Air admittance vents can be utilized in vented attics to minimize roof penetrations for plumbing stacks.
 
9.3 Armored/metal hoses from water service to all fixtures/appliances. And/or automatic in-home water sensors and shutoff system installed. Flooding due to leaking hoses and fittings is one of the most common insurance claims.
 
9.4 Lever style water shut off valves for easy emergency/vacation purposes.
 
9.5 Secondary water protection on roof. Self adhering polymer bitumen roofing underlayment, or seal joints in sheathing with foamed polyurethane or self adhering polyethylene or rubberized asphalt tape (minimum width of 6 inches).
 
9.6 Consider borate treated lumber for termite resistance.
 
10.0 Homeowner Awareness
 
10.1 Provide owners manual that discusses energy efficient and green features and their operation.