Part3 in my series – "How to build a better house". Last week we talked about advanced framing techniques, which in simple terms replaces lumber with insulation material and maximizes the wall that’s insulated. This effectively improves the thermal resistance or R-value of a wall. As a reminder on how important advanced framing is, let's look at the comparison of a standard wall vs a wall constructed with advanced framing again:

A standard wall assembly using R-13 batt insulation will have an effective R-value of 11.1. An "advanced" wall assembly will have an effective R-value of 14.6 or 30% higher than the traditional wall. 

This week I want to focus on the different kind of insulation materials we can use to use that give you the most energy efficient green home.

In general, insulation is one of the most important components in any responsibly built structure, especially in green buildings. Insulation reduces energy consumption and if properly installed, can reduce draft dramatically. From that perspective, any insulation material is a “green” product.

The choice of insulation material will be covered in my next article "Insulation techniques……or how to build a better house – Part4" and has a lot to do with where the insulation is installed (wall, ceiling, roof, crawlspace etc etc), the climate area you live in and the specific details of your wall assembly.

So let's look at some of the different kinds of insulation materials that are out there these days:

Fiberglass Insulation:
This is the standard in the building industry today. High-density fiberglass makes the same wall cavity 15 to 20 percent more effective in reducing heat loss. The majority of manufacturers now incorporate at least 30 percent recycled material, and there are quite few products that carry third-party verifications for their recycled-glass content. If Fiberglass insulation is used as a batt, it is important to know that most of them are manufactured with phenol formaldehyde as a binder, though some products use alternative binders or no binder at all. So be sure and investigate the contents of the product you want to use in your green home.

Cellulose Insulation:
Is primarily made out of recycled newspaper, but not always from post-consumer sources. It is often damp-sprayed into open cavities, or blown into closed cavities at relatively high density. Cellulose adds to the airtightness of the house—and by forming a good infiltration-barrier. It is also less quality control dependent in filling voids than fiberglass batts (in simple terms… not as easy to mess up

Rigid Foam Insulation:
Rigid foam insulation applied to framing yields added infiltration resistance, reduced frame conduction losses, and higher overall wall R-value. Extruded polystyrene (XPS) and polyisocyanurate (polyiso) rigid foam insulation used to be made with ozone-depleting CFC blowing agents, but when ozone depletion was identified as a major environmental problem, the CFCs were replaced with HCFCs through international agreement. HCFCs were eliminated from polyiso insulation as of 2003, but they are not scheduled to be totally eliminated from XPS until 2020. Polyiso is currently produced with hydrocarbon blowing agents. Expanded polystyrene (EPS) rigid foam has long been made with non-ozone-depleting pentane rather than HCFCs.

Spray-Polyurethane Foam insulation:
One of my favorite insulation materials, spray-foam is an excellent choice for most buildings. Though slightly more expensive than the other materials mentioned above, the qualities of spray-foam will give you "a lot of bang for your buck". As the name implies, it is sprayed into open cavities and quickly expands to about 100 times its original volume. Most manufacturers claim R-values of about R-3.8 per inch. Several manufacturers sell water-blown products though there are still quite a few that use HCFCs or hydrocarbon blowing agents which are harmful to the environment and your health. So again, beware of what you buy.

Of course, there are a myriad of products available on the market today. If you want detailed information, I have included some manufacturer links below. If you want to find out specific product details while you are in the process of building your home, try the product directory at http://GreenBuildingAdvisor.com (Paid subscription) or http://www.buildinggreen.com/ (Paid subscription). They have great product databases with all the relevant product information.

I should mention that most of these materials can be installed in different ways – Loose fill, batts, spray or rigid boards. What to use "where" and "why", will be covered in my next article.

Be sure and come back. Don't miss next week's article. Insulation Techniques… or “How to build a better house” – Part4

Links to other articles in this series:

Thermal Bridging… and how it affects a wall assembly – Part1

Advanced Framing Techniques – Part2

Some Manufaturer Links:

http://www.certainteed.com/- Fiberglass

http://www.applegateinsulation.com/ – Cellulose

http://www.knaufinsulation.us/ – ECOBatt

http://www.demilecusa.com/ – SprayFoam

http://www.icynene.com/

Sources:

http://www.greenbuildingadvisor.com/

http://www.buildingscience.com
http://www.toolbase.org
http://resourcecenter.pnl.gov
http://www.energysavers.gov

What we know today as "Advanced Framing Techniques", was originally developed in the 1960's as Optimum-value engineering (OVE) framing techniques under a Housing and Urban Development (HUD) initiative to cut the cost of houses by omitting unnecessary lumber. The approaches did not get widely adopted at the time. However, with the passage of time, many of the original OVE techniques have been incorporated in what we today refer to as "advanced framing". Advanced Framing includes OVE framing techniques such as increasing joist, stud, and rafter spacing to 24 in.; placing doors and windows on stud layout; and using stacked framing for direct load transfer. Application of advanced framing not only saves on lumber and labor costs, but also supports better insulation detailing and reduces the occurrence of drywall cracking.

The image below illustrates some of the advanced framing techniques.

Advanced framing, as the name implies, means using framing lumber intelligently in wood framing by:

1. use of common material dimensions (24-inch grid) as a basis for design to maximize material use and minimize waste and
2. efficient load transfer to reduce unnecessary framing members from the home.

As you can see in the illustration above, some of the techniques used include stack framing – allowing for the use of single top plates, elimination of wood beams/headers in non-load bearing walls, and two-stud corners. Framing around openings in exterior walls limited to those framing members needed for vertical load transfer or horizontal load resistance.

Looking at this from a broader view – what does this do for our exterior wall assembly and my house in general? Well… besides cutting back on material waste and material usage – which increases resource efficiency, one of the main goals of green building – incorporating these techniques allows us to install more insulation in exterior walls.

In simple terms: Advanced framing actually replaces lumber with insulation material and maximizes the wall that's insulated, which improves the whole-wall thermal resistance or R-value.

So let's look at a comparison of R-values in a standard wall vs a wall constructed with advanced framing:

A standard wall assembly using R-13 batt insulation will have an effective R-value of 11.1. An "advanced" wall assembly will have an effective R-value of 14.6 or 30% higher than the traditional wall.  

If you're a homeowner, you're probably reading this going: "How does this affect my wallet?" – I have some simple stats for you. Fully incorporating advanced framing techniques may result in:

• Materials cost savings of about $500 or $1000 (for a 1,200- and 2,400-square-foot house, respectively)
• Labor cost savings of between 3% and 5%
• Annual heating and cooling cost savings of up to 5%.

 (Source & detailed calculation: http://www.energysavers.gov)

So if you are currently in the market shopping for a home, ask if the home you're considering was built using advanced framing techniques or with other systems like SIPs or ICFs – which I will cover in future articles. If you are in the process of building a new home or undertaking a major renovation, ask your builder to incorporate these techniques. You will end up with a better home.

Links to other articles in this series:

Thermal Bridging… and how it affects a wall assembly – Part1 of 7

Sources:

http://www.buildingscience.com
http://www.toolbase.org
http://resourcecenter.pnl.gov
http://www.energysavers.gov
 

Cutting back unnecessary energy use is an easy way to keep your hard earned money in your pocket. Here are some suggestions you can do at home, at absolutely no cost to you.

Let the sunshine in. Open drapes and let the sun heat your home for free (get them closed again at sundown so they help insulate).

Rearrange your rooms. Move your furniture around so you are sitting near interior walls – exterior walls and older windows are likely to be drafty. Don't sit in the draft.

Keep it shut. Traditional fireplaces are an energy loser – it's best not to use them because they pull heated air out of the house and up the chimney. When not in use, make absolutely sure the damper is closed. Before closing the damper, make sure that you don't have any smoldering embers. If you decide not to use a fireplace, then block off the chimney with a piece of rigid insulation from the hardware store that fits snugly into the space (dampers don't shut fully without some leaking).

Eliminate wasted energy. Turn off lights in unoccupied rooms. Unplug that spare refrigerator in the garage if you don't truly need it – this seemingly convenient way to keep extra drinks cold adds 10-25 percent to your electric bill. Turn off kitchen and bath-ventilating fans after they've done their job – these fans can blow out a house-full of heated air if inadvertently left on. Keep your fireplace damper closed unless a fire is burning to prevent up to 8 percent of your furnace-heated air from going up the chimney.

Shorten showers. Simply reducing that lingering time by a few minutes can save hundreds of gallons of hot water per month for a family of four. Showers account for 2/3 of your water heating costs. Cutting your showers in half will reduce your water heating costs by 33 percent.

Use appliances efficiently. Do only full loads when using your dishwasher and clothes washer. Use the cold water setting on your clothes washer when you can. Using cold water reduces your washer's energy use by 75 percent. Be sure to clean your clothes dryer's lint trap after each use. Use the moisture-sensing automatic drying setting on your dryer if you have one.

Put your computer and monitor to sleep. Most computers come with the power management features turned off. On computers using Windows, open your power management software and set it so your computer goes to sleep if you're away from your machine for 5 to 15 minutes. Those who use Macintosh computers look for the setting in your Control Panels called "Energy Saver" and set it accordingly. When you're done using your computer, turn it off (see next tip). Do not leave it in sleep mode overnight as it is still drawing a small amount of power.

Plug "leaking energy" in electronics. Many new TVs, VCRs, chargers, computer peripherals and other electronics use electricity even when they are switched "off." Although these "standby losses" are only a few watts each, they add up to more than 50 watts in a typical home that is consumed all the time. If possible, unplug electronic devices and chargers that have a block-shaped transformer on the plug when they are not in use. For computer scanners, printers and other devices that are plugged into a power strip, simply switch off the power strip after shutting down your computer. The best way to minimize these losses of electricity is to purchase ENERGY STAR® products.
 

 If you're going to hike in the snow, you'll probably want to wear your wool socks. Not only do they insulate your toes from the cold, but your socks will still do a good job if a little snow or slush gets into your boots. That same principle applies for insulating wall cavities in places where sheep's wool is plentifully available.
But a new technology promises to make lamb's wool an even more practical choice for the building industry, as U.S. manufacturer SayrCo prepares to introduce WEKA semi-rigid insulation panels to market. The product is essentially a wool-based interior sheetrock with some serious R-value and other environmental benefits…Think of it as ‘sheeprock.'……….
The manufacturing process is rather simple and low-tech. Freshly shorn wool is thoroughly chopped, washed, and then mixed into a binder that includes quicklime and other natural ingredients designed to fortify the wool's natural fire, mold, and vermin resistance. The resulting slurry is then pressed into 4' x 8' or 4' x 12' sheets, air dried, and covered on both sides with the same type of heavy paper used in gypsum board.
The lightweight WEKA panels have an R-value of 6.5, and they can be mounted 3 deep on the indoor side of exterior walls to produce an R-19.5 assembly without stuffing any additional insulation into the cavities. As a result, builders can use 2 x 4 rather than 2 x 6 studs, and also eliminate the thermal bridging that is typical when conventional batts are used.
Installing WEKA panels is no more complicated than installing drywall. The panels use the same tape, mud, fasteners, and adhesives as conventional sheetrock while providing drywall and insulation in a single step.

Energy and costs savings through insulation

The WEKA panel is replacing conventional insulation and drywalls with one single rigid sheep's wool panel.
This results in reduced material and installation costs.
Up to 44% of a homeowners utility bills are due to heating and cooling costs, this panel can reduce your operating costs by more than 60%.

Natural Characteristics and Benefits of Wool

Wool is improving in-door air quality by absorbing certain air contaminants. Wool can absorb large quantities of formaldehyde (commonly present in buildings). Furthermore, wool can absorb and release moisture without degradation or significant loss of thermal resistance (up to 40% of its own weight). The insulation panels are made of sheep wool that has been treated with a natural stabilizing solution to provide pest and fungal resistance. The panels are efficient in preventing the formation of mold and can reduce existing mold through high alkalinity and by simply absorbing the humidity or condensate in air conditioned rooms. The high pH of 11 is stopping the growth of mold.

 Environmental advantages

According to Christian Tasser, the developer of WEKA, a similar product has been used in Italy for 10 years, and it has proven thoroughly stable and free of any issues. From that experience, Tasser can point to an important IAQ benefit: stabilized sheep's wool can absorb up to 40 percent of its own weight in humidity and water content, and then release it when conditions dry out. “It takes the humidity out of the room, and at the same time it neutralizes any kind of unwanted fungi or pests,” he said. “The wool also controls any air contaminants such as formaldehyde by drawing it into the wool, and it stays there.”
In addition, Mike Peterpaul of SayrCo aims for high environmental standards on the manufacturing side. “We're working with sheep farms within a 100 mile radius of our plant,” he said. “The energy footprint to manufacture the product is very, very low. The wool is naturally dried after it's washed, the water will be recaptured, plus the whole process has a very low carbon footprint,” he said.
Peterpaul expects to start shipping WEKA in quantity by August or September, 2010. He is looking to launch it through a network of 100-200 green oriented distributors. SayrCo intends to support the rollout with local advertising that draws builders, contractors, and consumers directly to those dealers.

Low Carbon Footprint

WEKA panels require no thermal treatment or chemical processes, which minimizes the energy input during the production of the panels. The WEKA panel is fully recyclable after the lifetime of the building.

LEED Points:

 -Thermal Comfort (2pt)

-Rapidly renewable material (1pt)

-Innovation and design process: light, recyclabe (5 pt)

-Optimize energy performance (2pt)

-Use of local materials 500 miles: FOB Athens,PA (2pts)

Structural Insulated Sheathing(SIS),Developed by Dow to help make building energy efficient homes easier for builders, STYROFOAM SIS™ is a 3-in-1 solution that provides R3-R5.5 insulating value, meets or exceeds structural codes, and is one-third the weight of OSB*. Because OSB and housewrap are not needed, STYROFOAM SIS™ reduces the number of trips around the house and saves on installation time and labor costs. The innovative STYROFOAM SIS™ Brand Structural Insulated Sheathing from Dow combines three functions in one product:

1.     Structural lateral bracing and transverse loads

2.     Significant insulation performance

3.     Water-resistive barrier

In addition to providing the racking shear needed for exterior walls, STYROFOAM SIS™ blankets both the wall cavities and the studs to shield against thermal bridging which minimizes heating and cooling loss due to air infiltration. STYROFOAM SIS™ also helps move the dew point from inside the wall cavity (where mold and mildew can accumulate and go undetected) to outside of the wall cavity where it belongs, and, when taped at the seams and joints, STYROFOAM SIS™ meets code for water-resistive barrier.

Builders are incorporating STYROFOAM SIS™ into "green" package options for their customers as a point of differentiation.  Made of up to 80 percent post-consumer recycled content by weight, STYROFOAM SIS™ is also ENERGY STAR-qualified and can save homeowners between $200- $500 per year*** in energy bills. The reduction in home energy usage helps reduce carbon emissions and may enable the use of a smaller HVAC unit, which could earn credits in the USGBC’s LEED program or NAHB’s National Green Building program. 

The thermal performance advantages of STYROFOAM SIS™ can also help builders earn the $2,000 U.S. Energy Tax Credit for energy efficient homes built in 2009. STYROFOAM SIS™ provides a high R-value (R-3.0 at 0.5" or R-5.5 at 1.0") without having to extend window and door jambs, and is cost-competitive with wood sheathing and house wrap in many instances, so builders can promote the benefits of insulation with little to no added expense.

STYROFOAM SIS™ Brand Structural Insulated Sheathing has won an MVP Award for "Most Valuable Product 2009" from Building Products  magazine, a Hanley Wood publication. STYROFOAM SIS™ was selected as a winner of this coveted award by a panel of judges comprised of builders, remodelers, architects and developers who evaluated product submissions based on their ability to reduce installation time, callbacks, or labor costs, and other factors that bring "value" to building professionals.

Click the link below to calculate energy savings for your home:http://building.dow.com/na/en/tools/calculators/usres_disclaimer_new.htm

 For all the information on this product go to: www.dowsis.com

What is thermal bridging and why is it important that we pay close attention to its effects in the homes we build?

The importance lies in the different materials we use to build our wall systems, how much of these materials we use and what conductivity these materials have. We all know that exterior walls have (or should have) insulation, and its purpose is to slow down movement of heat through our walls.

Most of you know about the R-value of insulation materials. R-value rates the materials’ resistance to heat-transfer: the higher the R-value, the lower the heat-transfer. The illustration above best shows how the different materials in the walls affect heat transfer.

We also know that most of our wall assemblies in residential construction are built with wood studs and wood sheathing on the exterior. Soft woods have almost 3 times the conductivity rate of fiberglass insulation, so heat transfers much more quickly through the parts of the wall assembly that are made out of wood, essentially bypassing the insulation. This process is called "thermal bridging" and it results in a lower overall R-value of your wall assembly. Most people mistakenly think that because they insulate their wall with R-19 fiberglass insulation, they have an R-19 wall, when in reality their wall has a much lower effective R-value.

What does that mean from a practical standpoint? Well, let’s put it in the simplest way possible: the more wood studs in your wall assembly, the lower the R-value of your wall.

How can we solve this and make our wall assembly more energy efficient? Obviously, by using less wood in our walls to allow for less thermal bridging and more insulation in the assembly.  But how exactly can we achieve this? There are several ways: we can use systems like SIPs (structural insulated panels), ICFs (insulated concrete forms) or use advanced framing techniques. I will post follow-up articles on all of these solutions in the coming days.

Links to other articles in this series:

Exterior Wall Assemblies… or “How to build a better house” – Part2 of 7

Sources: BuildingGreen.com , BuildingAmerica.gov , eeba.org

IMAGE CREDITS: Illustration by Julia Jandrisits

Your walls alone are not adequate to protect you from the sound, pests and weather outside. They are not as tough as you think. It is necessary to have a blockade between walls to keep the pests, cold and dampness out of the house and the heat and sound in. Some kind of insulation is already fitted in most of the homes, but they all aren’t created equally.

Many of the older homes are prepared through fiberglass insulation. Though fiberglass is low-priced and to some extent effective in controlling climate, but it saves small amount of energy and offers minimal protection. It can also be unsafe for your health. A touch of fiberglass makes your skin sore and itchy and inhaling a sharp fiber can lead to serious health problems. They can create scars in your throat that can cause more problems.

Spray foam insulation is an alternative to traditional fiberglass and it helps to construct very strong barriers between the outside world and your home. Spray foam solidifies as a spongy substance, as it is liquid polyurethane. Given that it applies in a liquid form, spray foam fills even in the tiniest cracks and enters the whole surface that is being treated.

While fiberglass can be easily torn, chewed, or easily displaced eventually, spray foam sticks everlastingly to that area. Its strength and texture makes it difficult for anything to enter through it. Even mold and water are discouraged to seep in and cause damage. Thus spray foam insulation is a better and safer alternative to another material.

The benefits of spray foam insulation also comprise of the betterment of soundproof walls. Loud voice is dampened by the broad surface. It can also be applied on floors and ceilings.

Spray foam is also called as ‘green material’ because it keeps the home warm during winters and cool during the summer. This way it saves far more energy than fiberglass.

Recyclable and renewable resources are also used to create spray foam and this way it helps in contributing to our environment and to the economy. Initially it seems to be expensive, but this insulation gradually helps you in saving money in the long run, as it increases the value of the home and saves a lot on your electric bills. Spray foam insulation is a safe, green alternative to other insulation materials with various benefits.

There’s a big debate in the green building industry about performance testing – should it be mandatory for new and existing construction and how much good will it do? As reported in the American Statesman on June 10, 2009 Austin just released the results of the first 310 homes that received energy audits under the new ordinance. The ordinance requires sellers to get energy audits of their homes and disclose the results to potential buyers. Austin Energy compiled these numbers from the first wave of audits:

86% of homes had ducts that leaked more than 10% – the rate considered acceptable for energy efficiency

The average amount of air leakage was 22% – WOW! This is the average of all homes tested – 1/4 of energy lost in leaking ducts.

The average loss in hard $$$$ is $260.00 a year per home. This is $260.00 of wasted electricity per home per year.

807,840 Total annual kilowatt-hours of electricity wasted by these houses — enough to power 67 average-size homes for a year

1 million Pounds of carbon dioxide emitted annually to produce the wasted electricity

$500 Average cost to seal ducts, after Austin Energy rebates, with a $120 average annual savings

$661 Average cost to add 6 inches of attic insulation, after rebates, with an average annual savings of $90

Now that’s some hard facts. How can anybody argue against performance testing?

Dallas does not have an ordinance like this – yet! But it would be in the interest of all consumers to know how efficient (or not) their house is before they buy it. If you are in the market for a new home in Dallas and would like to get it evaluated for energy efficiency before you buy, just give us a call at 214.550.5076 or email us to info@EGCDallas.com.