Items marked with (*) are not readily available commercial products
Building shell
1. Airtight envelope construction
2. High building R-Value
2.1 Building Code R Value * Basement Walls: 11 (southern WI) or 19 (northern WI) * Above ground walls: 21 * Ceiling: 49
2.2 ZEH R-Values, Seen in ZEH (WI Davenport Home, Colorado solar harvest home, South Chicago home)
* Basement Walls: 20, 30, NA
* Above ground walls: 28, 34, 25
* Ceiling: 60, 45, 42.5
2.3 Water materials/types - can be mixed, e.g., a ICF basement, stud walls and an SIP ceiling
2.3.1 Conventional ("Stick built)
* Made less conventional by exterior strapping to reduce thermal bridges, use of soy based foams
* Concrete basement insulated on inside (i.e., foam behind 2x4 studs and drywall) above ground on outside of wall
* Above grade walls: 2x6 wood or metal stud wall with blown in dense pack cellulose, icynene foam, fiberglass, may include external foam sheathing. etc
* Ceiling/attic: wood joist with blown in cellulose or fiberglass on ceilings, icynene foam if hot roof
2.3.2 Structural insulated panel (SIP) SIP R-value (other wall materials add R-value)
* 4.5" panel R-value = 17 * 6.5" panel R-value = 25
* 8.5" panel R-value = 33 * 10.5" panel R-value = 41
2.3.3 Insulated concrete forms (ICF)
* 6" wall R-value = 21 * Panels with more foam have higher R-values * Debate regard their R-value – as they have a "mass effect"
2.3.4 Autoclaved Aerated Concrete (AAC) (*) pre-cast concrete blocks with many small air bubbles
* R 1.05 per inch
* Also have mass effect
2.3.5 Strawbale (*)
2.3.6 Rammed Earth, etc (*)
Site Elements
1. Solar resource
* Open sunny sites are preferred for solar electric, solar thermal and passive solar
* Open site is needed for solar system(s) preferably within 150 feet of the home’s electricity panel and/or hot water tank
* Best site for solar energy systems is commonly a sunny south facing roof
2. Passive cooling resource
* Sites with a summer breeze are preferred for passive cooling
* Sites with mature trees (not evergreens) shading the house in the summer are preferred for passive cooling
* Vegetation to the west and northwest of the home protects the home from hot summer afternoon sun
3 Wind resource
* Vegetation to the west and northwest of the home protects the home from cold winter winds
* If a wind turbine is to be used:
1) Open high and windy site is preferred, and
2) site must be large enough for the tower and turbine to fall and hit only your property
Design elements
1. Moderate size – the not so big house
2. Home long axis should run within 20 degrees of east-west
3. To minimize outside wall to floor area (building costs and heat losses)
* Consider multifamily homes – conserve energy and resources through shared walls, utilities, etc.
* Two floors and rectangular – reduced building surface area
* Cathedral ceilings with lofts – reduced building surface area
* Earth bermed into south facing slope: opens up south-facing basements to daylight and passive solar – while making it a nice livable space
4. Home layout (rough ideas)
* Daytime living areas on south side of home
* Storage, bathing, sleeping areas on north side of home
* Garage on west or north side of home
* Porch on east side of home (morning sun and evening shade)
* Entryway vestibule – reduce door-opening losses and can also be a passive solar room
5. Roof – dark colored roofs are recommended in the Midwest’s heating dominated
Solar Ready Home
If the budget can not encompass the cost of solar systems – make the roof "solar ready"
1. Solar electric and water heating systems,
* Appropriate roof orientation with minimal shading from surrounding area (trees, buidling, etc.) and building elements (dormers, vents, chimneys, etc.)
* If the future location of the solar panels is known install:
1) small access catwalk in the attic extending from the attic hatch to the location of the conduit to the future location of the solar panels on the roof surface, and
2)blocking between roof trusses or rafters to provide a mounting surface for the panels.
2. Solar electric systems, very helpful if:
* Install ½" to ¾" conduit near the utility panel through a building cavity and extending into the attic. Clearly label the conduit and air sealed at the top and bottom.
3. Solar water heating systems, very helpful if
*Install two ¾ to 1 inch type L copper pipes from an accessible location in the mechanical room through a building cavity and extending into the designated attic. Pipes must be capped and insulated with 1/2" insulation rated for 250 0F
* Pipe joints should be reamed to reduce flow noise and bubbling and the cavity air sealed at the top and bottom. The path should be short and straight
* Install a four or six-conductor stranded thermostat control wire along with the pipes. Tape the wire to the outside of the insulated copper pipe and leave a coil of extra wire at each end.
Windows Higher the whole window R-value the better
* Common R-values of 5 to 3 on ZEH homes (U-value of 0.2 to 0.33)
* Heat mirror windows up to R of 12 (*)
Doors
Insulated metal exterior doors that are tight (i.e., no air leakage) in the door frame
Heating Ventilation and Air Conditioning (HVAC)
Space Heating Options
1. Passive Solar/Solar Tempered (also promotes daylighting)
1.1 Good window shades/coverings/window quilts must be used (exterior coverings are better than interior – but there are few good products)
1.2 South windows
1.2.1 Overhangs shades out the summer sun: in Wisconsin south facing windows with a sill height of 30" or more inches off the floor, should have a roof over hang of about two feet, or 30" or less inches off the floor, should have a roof over hang of about three feet.
1.2.2 Higher solar heat gain coefficient (SHGC) > ~0.6 for south facing windows
1.3 Other Windows
1.3.1 Low SHGC on East and West (SHGC < ~0.3) windows – particularly the west 1.3.2 Good window shades/coverings that are used
1.4 Appropriate amount of fenestration (values determined for Wisconsin)
1.4.1 Total widow area should equal 12% to 20% of heated floor area
1.4.2 South facing glass area should equal 6 – 8% of floor area
1.4.3 West facing glass area should equal 2 – 4% of floor area
1.4.4 East facing glass area should equal 3 – 5% of floor area
1.4.5 North facing glass area should equal 1 – 3% of floor area
1.5 Appropriate amount of thermal mass (color, location and coverings matter)
* Can include double thick drywall, masonry floors, fireplace masonry,
* Phase change materials could be used – but are not currently commercialized (*)
Active Solar Space Heating
1 Active Solar Thermal with fluid-filled panels. Will require a thermal dump during the summer. Also typically provide over 90% of domestic hot water during the non-heating season.
1.2 Types of panels:
* Flat plate – produce lower temperature water or
* Evacuated tube – produce higher temperature water, must be kept clear of snow, more effective during cloudy days
1.3 Panel orientation for winter space heating:
* Perpendicular to January and February sun angles (ideally sloping 50 to 55 degrees down from the horizontal)
1.4. Types of systems
* Solar thermal preheat for low-temperature hydronic system, usually includes water storage tanks
* Heat distribution in floors with tubes in Concrete (basement), gypcrete (first and second floors), grooved subfloor assembly (first and second floors), or heat distribution panels in walls (*) * High mass with sand bed under basement floor – can not be combined with other types of infloor hydronic in the same floor, no water storage tanks
* Solar thermal loops under floors between joists under floors – good retro fit may include water storage tanks
* Solar thermal coils in forced air system – good retro fit - good retro fit may include water storage tanks
2. Active Solar Thermal for solar air heating
2.1 Solar Wall® and similar solar air pre-heating products - rarely seen (more common on commercial buildings)
2.2 Passive solar sun space with fans that move warm air into other living areas
Biomass Stove Space Heating
1. Types
* Masonry (large thermal mass with heat storage and passive heating and cooling benefits)
* Freestanding – good idea to locate thermal mass nearby
* Fireplace insert
* Outdoor – must be clean burning
2. Fuels
* Wood
* Pellet/waste corn
3. Stove water jackets for:
* Space heating (typically low temperature hydronic)
* Domestic water heating
"Conventional" Space Heating
1. Ground sourced heat pump (also for cooling) – electrically powered
1.1 Most efficient
* Vertical well that enters ground water or pond loops
* "Direct Exchange (DX) system" where refrigerant runs through loops
* High coefficient of Performance (COP)
* Properly installed, commissioned and operated
2. High EER natural gas or propane furnace
3. Air sourced heat pump – generally not appropriate for northern tier state
Space Heating Distribution System
1. System options
1.1 In floor hydronic (good match with solar thermal)
* Low mass - low temperature
* High mass/sand bed – low temperature with slow heat release
1.2 Point source heating – biomass stoves
1.3 Forced air
1.4 Radiator hydronic – high temperature (poor match with solar thermal )
Air Conditioning Passive cooling
1. Elements of passive cooling
1.1 Shaded house (trees or vines growing over home)
1.2 Shaded windows
1.3 Windows located and used for cross ventilation
1.4 Ablility to move warm air up and out of home
* Solar chimney
* Operable transome or clerestory windows (avoid skylights)
1.5 Thermal mass (see passive heating)
1.6 Well ventilated attics – for homes with insulated ceilings
Active Low Energy Cooling
1. Whole house fans
2. Ceiling fans
3. Window fans
Active Energy Intensive Cooling
1. Window air and split air conditioners for spot cooling – high SEER/EER
2. Dehumidifyers – Energy Star (R) – on a hot day all you may need is to reduce humidity
3. Ground sourced heat pumps – forced air cooling (infloor cooling will not work in humid climates)
4. Central AC – (high SEER properly sized, ducts insulated in conditioned space, etc.)
Controlled ventilation (for bringing in fresh air and destratisfying air)
1. Ducted system with
* energy recovery ventilation (ERV)
* heat recovery ventilation (HRV)
2. Kitchen and bathroom fans (quiet fans)
2.1 Automated fan controls, controlled by
* Room humidity
* Room lights turned on
Water Heating
Active Solar Thermal with fluid filled panels
1. Types of panels
1.1 Flat plate – produce lower temperature water
1.2 Evacuated tube – produce higher temperature water, must be kept clear of snow, more effective during cloudy days
* Optimal orientation for year round water heating (ideally sloping degrees down from the horizontal)
2. Heat pump water heater - using interior waste heat (heat could be from solar air heating system, refrigerator, etc.)
3. On demand water heater (natural gas or propane)
3.1 For combination with solar water heating system use one that can accept preheated water
4. High efficiency conventional propane or gas boiler with storage tank
5. Desuperheater on ground sourced heat pumps – to date poor performer (*)
Lighting
1. Daylighting - best with reflected light, avoid direct light – works well with passive solar heating strategies
1.1. Shaded south facing glass with light materials beneath and outside the window (to reflect light into the home), and light color paints high on walls and ceiling to bring light in to the home
1.2. Solar tube lights – using double layer plastic window, insulate tube in uninsulated attic areas
1.3. Clerestory and transom windows
1.4. Sky lights – on east and north facing roofs, using insulated glass, with shading device
2. Electric lights
2.1. CFLs
2.2. Tube flourescents
2.3. LED light emitting diodes (*)
Appliances
1. Energy Star® Appliances: refrigetators, freezers, dishwashers, clothes washers, air conditioning, dehumidifers, computers, audio video equipment, ceiling fans, ventilation fans, phones, office machines
2. Small capacity/size units: Freezers, refrigerators, laptop v.s. desktop computer
3. Reduce extra-plug loads, such as: wine refrigerators, second refrigerators and water beds
Behavior of occupant:
1. Be a "Conserver" for example: line dry clothing, low flow shower heads, wash laundry in cold water, turn off lights and appliances when not in use, open windows on cool summer nights, operate window shades and house fans
Power Generation – self generation
1. Types batteries
1.1. Grid connected without batteries
1.2. Grid connected with batteries for emergency back up
1.3. Off grid with batteries (will also need a generator)
2. Solar electric system
* less shading the better
2.1.Fixed roof mounted – ideal orientation facing south within 20 degrees and tilting at 35 degrees plus or minus 15 degrees
2.1.1 Replaces existing roofing
* Solar electric shingles, and slates)
* Water proof mounting of aluminum framed solar electric panels over roof decking
2.1.2. Laminated onto roofing – standing seam metal roofing
2.1.3. Sits on existing roofing
* Aluminum framed solar panels clipped onto metal roofing
* Aluminum framed panels over shingles
2.2. Fixed yard – pole or rack mounted
2.3 Dual axis tracking yard – pole mounted
3. Wind turbines – like high open places on towers of at least 100 feet tall
Power Generation – utility green power generation
1. Enroll in the green rate offered by your electric utility
2. Purchase green tags for your utility power consumption
