| Feature Technologies |
| Following is an explanation of many of the building technologies we are using in our Demonstration Home. Some of these products are now common in the residential building industry while others are new. |
FLOOR SYSTEM: ILEVEL BY WEYERHAEUSER
Although developed 35 years ago, engineered floor systems have only become
a major factor in homebuilding the last few years as the price has become more
competitive with dimensional lumber. Our Demonstration Home uses the
FrameWorks Floor system which includes TJI Joists (Trus Joists) with
Timberstrand LSL Rim Board. The dimensional stability of TJI Joists helps them
resist warping, shrinking, and twisting which can lead to squeaky or bouncy
floors. The engineered joists are then joined together with a rim board using the
laminated strand lumber, which is designed so that it is always straight, true, and
consistent. In fact the main stair stringers are made from Timberstrand LSL as
the quality is so much better than a standard 2x12.
The FrameWorks Floor system is also ideal from an environmental perspective
as the components are manufactured from wood strands instead of sawn from
whole trees. And since the system is designed for each individual home, there
is almost no waste, another element of the LEED point system.
SUBFLOOR: ADVANTECH BY HUBER
AdvanTech is another product that has quickly become an industry standard by
combining the best features of plywood and oriented strand board (osb) flooring
panels. It is engineered for superior moisture resistance, design bending
strength, and design stiffness compared to both plywood and osb. Each 4x8
sheet is consistent, smooth, and backed by a 50-year limited warranty. Our own
experience shows that it does not have the moisture problems common with
other subfloor products.
AdvanTech is manufactured from wood strands like osb so it is considered
green. And Huber has a plant in Maine which cuts the shipping (LEED for
Homes awards material points for local items).
WALL AND ROOF SHEATHING: ZIP SYSTEM BY HUBER
We are thrilled that our demonstration home is one of the first in New Hampshire
to use the ZIP System Wall Sheathing! This new product is a result of the very
latest thinking in how to protect the building envelope from moisture while still
letting it breath. Each 4x8 wall panel is a 7/16” osb type panel with a water-
restive barrier included. The seams are simply taped after installation and you
have a complete water barrier (also known as the drainage plain). The Zip
panels eliminate the need for house wrap which is often poorly applied on site
and not properly taped. Because the system is much tighter than traditional
house wrap, it also controls drafts. And the panels are engineered to allow the
wall system to breathe. No wonder the ZIP System Wall won Building Products
Magazine 2007 Award for Most Valuable Product. (link)
The Zip System Roof is a structural panel with a built-in moisture resistive barrier
that eliminates felt or tar paper and H-clips. Similarly it is taped with the Zip
System tape after it is installed and is water tight.
The Zip System panel use wood strands and recycled material and is also
produced by Huber within 500 miles so it qualifies for LEED material points.
Better yet, it is an engineered system that takes into account the effect of
moisture on the home.
21st CENTURY INSULATION
One of the major components of the Demonstration Green Home is the
insulation package. Energy Star is a prerequisite of the LEEDs for Homes
program but there are different levels of Energy Star performance which used to
be measured using a star rating (1-5 stars) but is now measured by the HERS
index.
One of the limitations of a conventional frame wall is the “thermal break”
everywhere there is framing lumber on the exterior walls. We minimized the
breaks by using high performance framing techniques and eliminating as much
unnecessary wood as possible. We also insulated the headers over doors and
windows which are usually the largest thermal breaks.
Next we sprayed 1” of polyurethane closed-cell foam. The foam expands to fill
the bays between the studs and fills the plumbing and electrical connections
through the exterior walls. 1” is the amount required to achieve a true air barrier
in the wall. There is also a study showing that 1” of foam stops 70% of heat loss
from conductance through the wall insulation. We could have sprayed more
foam but it is very expensive. A good trade off would be to frame the walls with
2x4 instead of 2x6 studs and fill that with 3 ½” of foam but many buyers perceive
this as “cheap” construction. In fact, the only reason 2x6 exterior walls are
considered standard is that the R19 fiberglass batts commonly used is the
easiest way to meet the energy code.
Although developed 35 years ago, engineered floor systems have only become
a major factor in homebuilding the last few years as the price has become more
competitive with dimensional lumber. Our Demonstration Home uses the
FrameWorks Floor system which includes TJI Joists (Trus Joists) with
Timberstrand LSL Rim Board. The dimensional stability of TJI Joists helps them
resist warping, shrinking, and twisting which can lead to squeaky or bouncy
floors. The engineered joists are then joined together with a rim board using the
laminated strand lumber, which is designed so that it is always straight, true, and
consistent. In fact the main stair stringers are made from Timberstrand LSL as
the quality is so much better than a standard 2x12.
The FrameWorks Floor system is also ideal from an environmental perspective
as the components are manufactured from wood strands instead of sawn from
whole trees. And since the system is designed for each individual home, there
is almost no waste, another element of the LEED point system.
SUBFLOOR: ADVANTECH BY HUBER
AdvanTech is another product that has quickly become an industry standard by
combining the best features of plywood and oriented strand board (osb) flooring
panels. It is engineered for superior moisture resistance, design bending
strength, and design stiffness compared to both plywood and osb. Each 4x8
sheet is consistent, smooth, and backed by a 50-year limited warranty. Our own
experience shows that it does not have the moisture problems common with
other subfloor products.
AdvanTech is manufactured from wood strands like osb so it is considered
green. And Huber has a plant in Maine which cuts the shipping (LEED for
Homes awards material points for local items).
WALL AND ROOF SHEATHING: ZIP SYSTEM BY HUBER
We are thrilled that our demonstration home is one of the first in New Hampshire
to use the ZIP System Wall Sheathing! This new product is a result of the very
latest thinking in how to protect the building envelope from moisture while still
letting it breath. Each 4x8 wall panel is a 7/16” osb type panel with a water-
restive barrier included. The seams are simply taped after installation and you
have a complete water barrier (also known as the drainage plain). The Zip
panels eliminate the need for house wrap which is often poorly applied on site
and not properly taped. Because the system is much tighter than traditional
house wrap, it also controls drafts. And the panels are engineered to allow the
wall system to breathe. No wonder the ZIP System Wall won Building Products
Magazine 2007 Award for Most Valuable Product. (link)
The Zip System Roof is a structural panel with a built-in moisture resistive barrier
that eliminates felt or tar paper and H-clips. Similarly it is taped with the Zip
System tape after it is installed and is water tight.
The Zip System panel use wood strands and recycled material and is also
produced by Huber within 500 miles so it qualifies for LEED material points.
Better yet, it is an engineered system that takes into account the effect of
moisture on the home.
21st CENTURY INSULATION
One of the major components of the Demonstration Green Home is the
insulation package. Energy Star is a prerequisite of the LEEDs for Homes
program but there are different levels of Energy Star performance which used to
be measured using a star rating (1-5 stars) but is now measured by the HERS
index.
One of the limitations of a conventional frame wall is the “thermal break”
everywhere there is framing lumber on the exterior walls. We minimized the
breaks by using high performance framing techniques and eliminating as much
unnecessary wood as possible. We also insulated the headers over doors and
windows which are usually the largest thermal breaks.
Next we sprayed 1” of polyurethane closed-cell foam. The foam expands to fill
the bays between the studs and fills the plumbing and electrical connections
through the exterior walls. 1” is the amount required to achieve a true air barrier
in the wall. There is also a study showing that 1” of foam stops 70% of heat loss
from conductance through the wall insulation. We could have sprayed more
foam but it is very expensive. A good trade off would be to frame the walls with
2x4 instead of 2x6 studs and fill that with 3 ½” of foam but many buyers perceive
this as “cheap” construction. In fact, the only reason 2x6 exterior walls are
considered standard is that the R19 fiberglass batts commonly used is the
easiest way to meet the energy code.
| A lot of the information one sees on green building focuses on the materials that go into the home. Yet the LEED rating system only allows a maximum of 8 points out of a possible 129 for environmentally preferable products. Instead, many of the needed points come from using products and systems that allow you to take advantage of the latest advances in building science. Our evolving understanding of how a home works as a unified system points to the importance of materials that aid in energy efficiency, indoor air quality, and weather resistance. |
SEPTIC SYSTEM: PRESBY ENVIRONMENTAL ENVIRO-SEPTIC
When it comes to the septic system in our Demonstration Home, there is only
one logical choice and that is Enviro-Septic. This system has become so
common that we often forget what a break-through it is. The main component is
a corrugated, perforated, high-density plastic pipe with a series of ridges that is
covered with a mat of coarse plastic fibers. Unlike a conventional system that
treats the waste effluent over soil, the Enviro-Septic treats effluent in the pipes
before releasing leachate into the surrounding soils. Thus it treats septic tank
wastewater more efficiently and completely.
Another major benefit is the small field size required compared to conventional
systems. In addition to saving money in fill, this allows us to disturb less of the
building site. Since the LEED point system encourages the minimum impact on
the building lot and discourages the planting of too much grass, the use of the
Enviro-Septic system contributes to the rating.
As an added benefit, Presby Environmental, Inc. uses recycled plastic and the
units are manufactured in Whitefield, NH. Testing shows that the Enviro-Septic
lasts longer than a conventional system which adds to the durability factor that is
a cornerstone of LEED for Homes.
GEOTHERMAL:
Below is the operating cost data for our geothermal system (heating, cooling, domestic
hot water) since the Demonstration Green Home has been lived in starting in late 2008.
The cost to run a geothermal heat pump is in extra electricity as you purchase no oil or
propane.
This home has a “standing column” which piggybacks off the well that is drilled for
domestic water use. A standing column is a hybrid between an open loop and closed loop
system. The water comes from the well and circulates through the geothermal heat
pump. Most of it is returned to the well although some of it is bled off as needed to make
the heat pump run efficiently and to prevent any icing in the well. A standing column
collection system keeps the upfront installed cost of doing geothermal down while being
very efficient.
Our system qualified for a $6700 rebate from Public Service of NH (PSNH) which about
offset the extra cost of the Climate Master Tranquility geothermal heat pump. Costs
associated with the standing column system include $400 extra for the well (assuming you
have adequate water flow by 400’), $2000 in extra electric work, and about $6000 to
upgrade the well pump system.
45 Creekwater Lane, Loudon, NH
Electrical Usage
* Billing period for Nov 18, 2008 – Jan 19, 2009 with 62 day billing cycle resulted from
winter ice storm.
May through most of June billing period reflects little geothermal usage as outside
temperature margins remained warm/cool enough neither of which required heating nor
cooling.
Below is the operating cost data for our geothermal system (heating, cooling, domestic
hot water) since the Demonstration Green Home has been lived in starting in late 2008.
The cost to run a geothermal heat pump is in extra electricity as you purchase no oil or
propane.
This home has a “standing column” which piggybacks off the well that is drilled for
domestic water use. A standing column is a hybrid between an open loop and closed loop
system. The water comes from the well and circulates through the geothermal heat
pump. Most of it is returned to the well although some of it is bled off as needed to make
the heat pump run efficiently and to prevent any icing in the well. A standing column
collection system keeps the upfront installed cost of doing geothermal down while being
very efficient.
Our system qualified for a $6700 rebate from Public Service of NH (PSNH) which about
offset the extra cost of the Climate Master Tranquility geothermal heat pump. Costs
associated with the standing column system include $400 extra for the well (assuming you
have adequate water flow by 400’), $2000 in extra electric work, and about $6000 to
upgrade the well pump system.
45 Creekwater Lane, Loudon, NH
Electrical Usage
* Billing period for Nov 18, 2008 – Jan 19, 2009 with 62 day billing cycle resulted from
winter ice storm.
May through most of June billing period reflects little geothermal usage as outside
temperature margins remained warm/cool enough neither of which required heating nor
cooling.
| UPDATED: AUGUST 2009 |
|
Next we used the Certainteed Blow-in-Blanket (BIBS) system which uses small fiberglass pieces blown behind fiber
netting. Properly applied, this system achieves a seamless blanket with uniform density while filling in gaps
behind pipes and outlet boxes. This ensures a uniform R value throughout the wall cavity and helps control air
infiltration. The result is slightly greater than an R4 per inch which when added to the R6 to 7 of the foam results
in a conventional 2x6 wall with an R value of 25 to 26, and more importantly, no air infiltration. We feel this
combination achieves the best ratio of price to performance currently available.
An insulated space is needed for the geothermal heat pump and the Energy Star raters also prefer that the
foundation walls be insulated (as opposed to the basement ceiling). We installed R5 rigid foam and then R13
batts in a 2x4 frame wall around the foundation. The attic has an R49 blown cellulose with an Energy Star
compliant scuttle cover. The expected HERS rating is somewhere around 60 which would be a 5 stars + rating.
The other options for a high performance house would be a double wall system or a structural insulated panel
(SIP). Either will add considerably to the cost. Since we are limited by current exterior door and window
technology (that is where the air infiltration comes from in a tight house), you would need to do a real cost benefit
analysis to see if these options would pay back your investment. Of course, if you decide they do, we will be
happy to build it with you!
netting. Properly applied, this system achieves a seamless blanket with uniform density while filling in gaps
behind pipes and outlet boxes. This ensures a uniform R value throughout the wall cavity and helps control air
infiltration. The result is slightly greater than an R4 per inch which when added to the R6 to 7 of the foam results
in a conventional 2x6 wall with an R value of 25 to 26, and more importantly, no air infiltration. We feel this
combination achieves the best ratio of price to performance currently available.
An insulated space is needed for the geothermal heat pump and the Energy Star raters also prefer that the
foundation walls be insulated (as opposed to the basement ceiling). We installed R5 rigid foam and then R13
batts in a 2x4 frame wall around the foundation. The attic has an R49 blown cellulose with an Energy Star
compliant scuttle cover. The expected HERS rating is somewhere around 60 which would be a 5 stars + rating.
The other options for a high performance house would be a double wall system or a structural insulated panel
(SIP). Either will add considerably to the cost. Since we are limited by current exterior door and window
technology (that is where the air infiltration comes from in a tight house), you would need to do a real cost benefit
analysis to see if these options would pay back your investment. Of course, if you decide they do, we will be
happy to build it with you!