ENERGY STAR for Homes Version 3: Assured Performance With Every Labeled Home

ENERGY STAR for Homes Version 3: Assured Performance With Every Labeled Home


Welcome to a presentation on the new Version
3 specifications. For the first time since ENERGY STAR was introduced in the market in
1995, EPA can now assure performance with every labeled home. For the next hour, weíll
cover how we can do that and how these new specs bring complete building science to the
housing industry for the first time. Letís start with ìwhat is ENERGY STAR for
Homes?î Essentially ENERGY STAR does two things: we
define what is truly energy efficient; and then we provide recognition to our builder
partners for their commitment to the program. All of
this is voluntary, and must work with the housing industry in a way that meets their
business objectives. Growth has been exponential since we gained
traction in 1999-2000. Weíve grown to over 1.2 million homes, and saw some decline in
growth during the housing market recession around 2007, but saw an increase again last
year, even when the market continued to struggle. You can see from the market penetration numbers
that weíve achieved that energy efficient builders are doing well in the market. There
was a 40% increase
in market penetration in from 2007-2008 alone. Last year, almost 1 in 4 homes built earned
the ENERGY STAR label. Builder interest in the program has increased
as well. 30 has grown to 300 builder applications per month.
So if ENERGY STAR is the solution, whatís the problem and performance issues weíre
trying to address? It comes down to our core brand promise. We
try to achieve truly energy efficient homes; much better than code, we must be cost-effective,
and we must treat homes that meet or exceed consumer expectations.
The performance we go after is the four cornerstones that are made possible with building science.
They are home with lower utility bills that are more comfortable room-by-room, have healthier
environments, and are much more durable. We get there by controlling air-, thermal-,
and moisture-flow. If we donít build as a system and only implement energy efficient
pieces, we canít control these things and create failures for the home.
Letís review how these occur, and start with air leakage.
With air leakage, you need to know the critical applications. Two of these are the sill plate
to the foundation, and sill plate to the flooring. Hereís an IR image that shows just how much
air leakage occurs
without proper sealing at this application. The light colors show warm surface temperatures
and dark colors show cold surface temperatures. So you can see just how much air leakage is
coming through. Doors, windows, and sill plates represent
~1/2 mile of cracks throughout the home. Each window and door has a gap that must be fully
sealed for them to work. Another major gap just beginning to be recognized
as an important building sealing detail is the air gap between the sheet rock and the
top plate, where there is an adjoining attic above. Attics can get extreme temperatures,
creating substantial driving forces at that gap.
Another source is through penetrations (often leaky ducts) that go through the attic. The
warm air melts the snow in winter. Once the snowmelt reaches the eave, it cools and becomes
ice. This can block drainage, and go up underneath the roofing, causing damage to materials.
Next item is insulation installation issues. This is a significant problem because installers
are paid by the piece; not how well the insulation works. Key problems surfacing, mostly with
batt products, are gaps voids and compression. These can lead to convective losses that undermine
the performance of the product. A gap like the one shown through this IR image
will be there for the life of most buildings. People donít tend to rip off sheet rock and
fix air sealing issues with existing homes. Hereís a typical type of compression detail
You can see the compromise in performance from this image, which will last forever in
the home. Another way we see misalignment is through
building practices like inset stapling of batt insulation. The installer here staples
the tabs of the insulation to the inside face of the stud, often to expose the stud for
gluing and nailing of sheetrock. But sheetrock can be installed without gluing. Weíre accepting
systemic misalignment for certain installations. Hereís why the misalignment is so important:
if I were to highlight the air spaces on both sides of insulation that has been inset stapled,
there are enormous gaps. Imagine if the walls are extremely cold on a winter day. The only
thermal resistance between the inside and outside air is the sheathing and siding, which
doesnít provide much thermal resistance. Itís very likely that that air space on the
outside wall would be freezing. Because of the thermal transfer, the inside spaces, set
at 70 degrees, are more likely to be in the mid-60ís.
The convective flow between the two air spaces
can bypass the intended purpose of the insulation altogether.
This image shows how it can manifest itself on a winter day. The insulating is hardly
working better than the wood studs between them. The walls
should be the same color as the roof shown
at the bottom of the image, but there is hardly any control of thermal flow due to the systemic
misalignment of inset stapling. The outside sheathing on a winter day is extremely
cold, and the air space between the framing of the two floors is heated to room temperature.
With the gaps, voids and compressions in this insulation, thereís very little chance that
there isnít condensation on this outside wall as the warm air meets a cold surface.
The potential exists for mold and moisture if the wetting exceeds the builder materialsí
ability to dry. Itís a risk we donít need in construction.
Again this IR image is strong evidence of a significant problem. The band joist is exploding
heat because the insulation isnít working properly in that building application.
Another significant detail that occurs is misalignment at the ceiling. Here is an image
of insulation draped across a false sloped ceiling, leaving misalignment gaps.
The ceiling goes into extremely hot temperatures during summer.
Another case of systemic misalignment is strapping insulation below the ceiling framing. This
is a consistent air space between the insulation and sheetrock below.
We see a very cold ceiling in the winter from an IR camera.
There are also critical gaps in attic hatches and dropdown stairs.
There are also significant problems in cases where insulation is on a flat conditioned
to unconditioned floor intersection, such as a bonus room or cantilever. In summer the
heat can flow around the insulation, creating a hot floor for the bedroom above.
In the winter, the warmer air in the room flows out to the unconditioned space.
Thereís no chance that this insulation detail would be touching the floor above, creating
a thermal enclosure. And when this happens you wind up with a cold
floor in winter, and hot in summer. To show the importance of the whole system,
hereís a house with walls and windows that perform well, but the slab edge at the bottom
is a superhighway of heat transfer. This will effectively suck heat from the bodies standing
on the floor inside. Air barrier problems are also significant.
In this case, fibrous insulation does not equal an air barrier. It will stop thermal
flow, but not airflow. So we need a 6-sided air barrier in contact with the insulation
for the thermal insulation to work properly. The fibrous insulation here is dark and discolored.
The driving force is driving air through this insulation, making it a filter for dirt and
dust. Here is an infrared image of an attic kneewall
in summer with inadequate air barrier. This is a kneewall in the winter. The r-19
insulated space between the studs is performing far below its rated r-value.
Hereís a picture of a bedroom, where on the backside of the wall is a sloped ceiling going
down to a garage via unconditioned space. You can see from the center image that this
wall is very hot, likely above 90 degrees. When the home was retrofitted properly with
a 6-sided air barrier, however, the IR image shows much improvement in insulation performance.
Another key detail for stopping air flow is where insulation runs up into the eave.
Hereís an attic eave surface from the interior on a cold winter day.
In summer itís like a strip heater on the edges of the building.
Hereís another detail where the drop ceiling occurs, and the insulation runs across without
a lid. The reason this is so important is that this
leads to a thermal bypass without the air barrier.
This is the same thing shown via IR image. You essentially have a complete thermal connection
between the attic and the house. Hereís a drop ceiling getting extremely hot.
Thermal bridging occurs when lack of insulation or poorly installed insulation allow for thermal
flow thatís unintended. This is much more wood than weíd need to
hold up a house. This creates a very big thermal bridge, where
heat is transferring through the studs much more quickly than it would with properly installed
insulation with air barrier. Another issue occurs at corners and wall intersections.
The intersection of studs creates an air space, which leads to cracking at corners.
Hereís an IR image of wall intersection where studs create uninsuilated space.
Lastly, with thermal enclosure, windows need to be addressed.
Older windows that are not high-performance let much more heat transfer occur.
HVAC Quality installation is another part of making a high-performance home. Often the
builder and contractor are working together to achieve the smallest cost, rather than
greatest performance. Essentially you pay for a 13 SEER, but get
the performance of an 8 or 9 SEER because of how the system actually performs once installed.
Here are some examples of other issues that have to do with quality installation.
Leaky ducts mean that the air being conditioned isnít getting to its intended location.
Also ducts that are laid out without proper design and installation create significant
problems. Flex duct, for example, comes in 25ft rolls. By cutting the duct to fit a direct
route, we cut back significantly on air flow resistance. Every bend creates the equivalent
of ~6-8 feet of extra duct length. There is likely very little airflow coming out of B.
We also need to watch compression of ducts so they maintain enough volume to sustain
airflow. This duct is pinched like a garden hose, but
instead of stopping water flow, itís stopping the flow of conditioned air.
There are also ventilation problems. We need to make sure that moisture and pollutants
can escape the home. Condensation is a good indication of poor ventilation. But this can
exist even where condensation does not. There are also pressure balancing problems,
if homes arenít properly equipped with systems and fans to balance air pressure.
This dark link in the carpet is an indication of pressure balancing problems, as the air
is trying to escape one room through the most direct route.
This is a diagram of why this happens. The air handling unit pushes air into the bedroom,
which then canít find its way back to the central return. Once the bedrooms are pressurized
to capacity, you stop getting the heating/cooling/dehumidification that the system is supposed to provide, which
can lead to setting T-stats higher in the winter, lower in the summer, and compromising
some roomsí comfort. You can see from the change in readings on
the right that when a bedroom door is closed and the room goes into negative pressure,
air gets pulled into the attic through the light fixtures, and in just 20 minutes, the
ceiling temperature changes 2 degrees. Another example is the gap between the sheetrock
and top plate. This issue also affects how we place appliances.
Clothes dryers are usually 250cfm airflow to remove moisture in clothes. This creates
a very big air exchange and creates a negative pressure in the zone.
The top of the water heater has a big hole at the exhaust. These exhaust fumes are easily
pulled back into the house. A good indication of a problem exists at the
bottom of this water tank where flame roll-out appears to be occurring.
Hereís a wall of a family room with laundry room on the other side. With the dryer vent
going through the wall up to the hot attic, thereís always a hot surface condition.
After running the dryer for 40 minutes, the wall reaches as high as 90 degrees, which
will compromise comfort. Lastly, there are filtration problems when
it comes to HVAC systems. Filters often have large air gaps around the
sides and tops, compromising performance. They leave lots of particulates in the air.
Then, there is the water management system, which is important to be comprehensive as
well. Think of blow-drying your hair after a shower.
It might take just a few minutes. With a piece of insulation between the dryer and your hair,
though, it will take hours, at best, to dry. This is what has happened with high performance
homes. Theyíre so well sealed and insulated, that they have no tolerance for drying. If
they get wet, you have almost certain moisture problems. It becomes incumbent on Version
3 to include water management items to avoid these issues in the first place.
We need to look at draining moisture from the home as a system, including roofs, walls,
materials, and foundation. Here is a house without any drainage plane
on the walls. If moisture gets behind the siding, there is a serious condition for getting
the OSB sheathing wet. Also every window leaks, eventually. Without
pan flashing, there is much greater potential for damage.
Here is one case where there was enough moisture that the material couldnít dry, and it led
to mold and dry-rot issues. Also the slits in foundation drains intended
to remove water from the foundation can let sediment in. These drains can clog easily
over 7-8 years. Since most homes last 100 years, it would make sense to install drain
tiles that donít clog in the first place. Another critical area is where the roof intersects
with an exterior wall. Without proper flashing, IR images show just how wet it gets at this
juncture. We should also be protecting materials onsite
so they donít get wet in the first place. Those are the performance problems we believe
need to be addressed for assured performance in every home.
And thatís what we attempted to address with ENERGY STAR Version 3.
Parts will not get this done. None of this gets you a complete system.
For ENERGY STAR Version 3, we ensure everything needed for complete systems is included in
the specifications. We started with the underpinnings of controlling
air flow, thermal flow, and moisture flow, and included efficient equipment and 3rd party
verification items to ensure high-performance and complete the building science picture.
All of these boxes come with every single labeled home.
The way this works is by starting with a baseline specification which ensures the home is at
least 15% more efficient than code, using similar requirements as with Version 2. There
are still prescriptive and performance paths for getting to this level of performance.
After this, there are mandatory checklists. The two for HVAC are for the contractor and
for the HERS rater. The systems ensured by the mandatory checklists
offer complete building science for every labeled home. Weíll now go through the basic
requirements of each of these checklist categories. The first component targeted by the thermal
enclosure system is air leakage. Version 3 targets the most critical applications first,
requiring flashing and sealing, as well as insulation.
Typical details like these require a visual inspection, as well as a blower door test
to ensure the house is tight. This is one option for sealing the intersection
of drywall at the top plate, using a foam seal.
Hereís what it looks like being applied. Another option for this detail is spray foam.
We care more about the what, not how. Most products and solutions are permissible under
the specifications, as long as they address the intent of the guideline.
Hereís a photo of the sealing from the top that was done on a retrofit application.
Then ENERGY STAR requires insulation R-value (quantity) and prescribes installation measures
(quality) for the home. EPA is material and product neutral, so it does not matter what
material you use, as long as it meets these two requirements. EPA seeks to avoid gaps,
voids, compressions, and misalignment in insulation. The insulation must be installed to RESNETís
Grade I level. The only exception is when rigid insulated sheathing is installed, the
inside wall may have Grade II installation. A very critical application is the band joist.
This is almost impossible to achieve Grade I using fibrous insulation batts, so EPA recommends
spray foam insulation here. There are also pre-made assemblies sold by
some Structural Insulated Panel manufacturers for band-joist applications.
Here is a good example of insulation and blocking applied below an above-garage bonus room.
As you can see, it takes a lot of insulation to fill these spaces.
Another option for filling these spaces is spray foam.
Another option is Structural Insulated Panels, which will ensure r-value and full alignment
at the floor. Another key place to get the installation
right is the openings between the home and the attic. Here is a large thermal hole. A
common solution is adhering batt insulation to the back of the hatch and applying proper
gasketing and weather stripping around the perimeter. The only concern with this method
is longevity. Another way to go is rigid insulation, which
is more durable than the batt. They also make Structural Insulated Panels
specifically for the purpose of an attic hatch. We also mentioned the importance of slab-edge
insulation in completing the thermal enclosure system. You can apply insulation to the inside
as shown here. You can also bevel the edge to ensure a proper
surface for interior flooring materials to go in.
Or you can put the insulation on the outside and use a protective layer like fibrous cement
board or metal flashing piece. We expect insulation on the outside when using
a post-tension slab. Air barriers are critical for insulation performance
as well. Hereís an image of an attic kneewall where we expect a solid air barrier such as
OSB, sheet rock, or thinboard sheathing. Air barriers are also critical where construction
details leave exposed insulation as with behind a tub or shower. Here you can see these details
were coordinated so that both insulation and an air barrier could be installed.
In all climate zones, air barriers must be installed with any dropped ceiling.
Also required at the attic eave to stop wind-washing of the blown-in insulation in the attic. Here,
cardboard wind baffles were used as an air barrier.
If you often have severe weather, you may consider using more durable products like
foams and plastics. Then, thermal bridging is addressed within
a complete thermal enclosure system. There are five options for handling this requirement
at walls. One is advanced framing. Hereís a detail where an interior and exterior
wall meet. We need to make sure insulation can go behind that assembly, using a lattice
strip as shown here, or using other details. You may also leave a gap between the studs,
allowing sheetrock to slide behind. There are many ways to achieve the intent of the
requirements. Wall framing requires the use of wood only
where necessary to allow for maximum R-value throughout the home.
In addition, insulated headers are required. The other option is using rigid insulated
sheathing on the outside. The three other systems available are Structural
Insulated Panels, double wall framing, or Insulated Concrete forms.
On top of wall assemblies, attic eaves must be constructed to reduce thermal bridging.
One way to achieve this is via raised-heel trusses, which raise R-value by creating more
space for full-depth insulation. Another way to meet this requirement is using
a high R-value plug above the wall to maintain the required R-value as prescribed by climate
zone. The last part of thermal bridging is for raised
platforms in the attic, for HVAC or walking. The last part of the complete thermal enclosure
system is the high performance window. We have an amazing value proposition with
Version 3 homes. Competing with existing homes which are often as bad as the thermal image
shown on the left, Version 3 homes offer a complete thermal enclosed system as displayed
on the right. This will become the standard of quality that people expect when purchasing
new homes throughout the country. This takes us to the next system: HVAC quality
installation. The requirements here address the performance compromise we often find with
high-efficiency equipment operating in a poorly designed system. A detailed checklist for
the contractor and the HERS rater ensure that full performance potential is being reached
by the equipment. The HERS rater will ensure that ducts are
installed properly without compressions, extended lengths, and bends.
The rater will also check that boots are attached and air-tight, without large gaps where air
can leak out. Pressure balancing will be assured with a
transfer grille. Grilles are sometimes installed above the
door, and have sound and visual privacy features installed.
Door manufacturers may also create pre-hung doors with transfer grilles so that no additional
installation is required. The second way to pressure balance rooms is
via jump ducts in the ceiling. These, however, are two more penetrations in the attic that
may compromise temperature control. The third option is a dedicated return from the bedroom
back to the air handler. Ventilation is required in every home. This
can be done with an exhaust-only system as shown here.
Another option is a duct that comes from the outside of the home back to the central air
handler unit to provide fresh air supply. The downside of these two systems is that
air must be made up through holes and cracks in the home. This doesnít offer complete
air control, but is lower cost. More expensive balance systems like energy
recovery and heat recovery ventilators are available.
In addition, spot ventilation is required in bathrooms and kitchens.
Filtration installed to at least MERV 6 is required, with installation that will not
allow air to bypass the filter. Whatís revolutionary about Version 3, is
that for the first time, we can approach the HVAC industry and say that standards that
have not been followed per status quo can now be followed with complete confidence,
allowing properly sized systems to be installed. The value proposition for HVAC, is that homeowners
will finally get what they pay for. Theyíll get something that everyone buyer deserves:
comfort. Lastly, fresh, filtered air will be available in every home.
This takes us to the last system in Version 3: Water management. The first part of this
is water-managed roofs, including heavy membranes at all penetrations and valleys.
In cold climates, we require membrane materials to extend inside, up the roof, which is critical
because of the extra abuse in cold climates with snow and ice.
In addition, any exposed roof sheathing should be equipped with drip flashing.
At walls, kick out flashing is required so water is diverted away from walls.
Advanced materials like premade plastic diverters exist for this.
Every window and door must have pan flashing materials installed.
There are pre-made plastic pans for this purpose. And then every wall must complete the picture
with a complete weather-resistant membrane, properly coordinated with the windows and
draining completely to the ground. This can be done with house wrap, or with
building paper. Rigid insulated sheathing used to meet the
thermal bridging specifications can often be taped and act as an exterior weather resistant
membrane as well. At the foundation, the drain tile must be
wrapped with a fabric filter in certain climate zones. You can assemble this in separate pieces.
You can also use a pre-made drain tile that comes with a fabric filter wrapped around
it. Version 3 also specifies a capillary break
under the slab for homes built in wet climate conditions. For slab-on-grade construction,
the gravel is exempt, but the plastic capillary break is required.
Crawl spaces must also be lined with a capillary break.
One of
the benefits of this capillary break of gravel and poly is that it serves as the first step
toward an effective radon-resistant system. Extensive amounts of homes in the US are exposed
to high levels of radon. Lastly, the home must be drained so water
runs away from it. On the inside of the homes, materials must
be selected and used properly. This image shows a vinyl wall covering in a hot humid
climate which traps the hot air trying to come into the home and leads to mold and
mildew problems. Protection of materials in wet climates is
required so they donít go into the home already moldy and wet.
Because of these new requirements, Version 3 homes offer better protection for the largest
investment of a lifetime, require less long-term maintenance, and due to the prevention of
mold and moisture problems, offers a healthier environment for owners.
In any home, we want to keep
the inside temperature at a conditioned 70 degrees. Because of the
thermal bridging in existing homes, much more
energy is used to achieve this constant temperature, and often comfort issues arise. Also for Version
3, water protection (for roofs, walls, foundations, etc.) is a system and offers a complete break
to the outside environment. This is an incredible
value package for every homeowner, and will take new home construction
to the next level. Join us in this program, and continue working with ENERGY
STAR as its value continues to increase. Thank you for
your interest in Version 3.

Comments

  1. Post
    Author
  2. Post
    Author
    ron davison

    How about a pressure balancing door?
    Have enough plenum and inside sound absorption board to add privacy and sound control.
    To reduce any undesired level of compromise between flow and sound absorption. (Add a sliding cover over inside vent assuming that it can't be solved completely without compromise.)
    This would provide the air balancing needed without any labor other than hanging the door.
    ideation 1-28-2018 Ron Davison

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