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building energy house

Adding Insulation for Energy Efficiency part 2

The last time we checked in on the topic of insulation and insulating a house to the point where it wouldn’t need a furnace was back in December. Sheesh. The cold has broke here in the northern great lakes region, and while there is still a chill in the air some days, we seem to be headed right into spring. The good news is, insulation is not just a winter topic. Good insulation in your home will help keep it comfortable all year long. And keep your energy bills down. And so we forge ahead with adding insulation for energy efficiency.

Previously, I walked through the calculations to determine the payback period for adding insulation. Today let’s look at a couple of examples of how that might work our in practice.

  • R-value of the initial insulation (Ri)
  • R-value of the final insulation (Rf)
  • Cost of insulation (Ci)
  • Efficiency of the heat system (E)
  • Cost of energy (Ce)
  • Number of Heat Degree Days for the year (HDD)

And the equation looks like this:

P = (Ci * Ri * Rf * E) / (Ce * (Rf – Ri) * HDD * 24)

OK, take a deep breath. We’re about to do some math!

Example 1: Fiberglass Insulation Upgrade

For our first example, we’ll use the following situation: A house in Wisconsin is going to have its insulation upgrades. It currently has fiberglass batting with an R-value of 13, and will be upgraded to fiberglass batting with an R-value of 19. The cost of the new insulation is $0.41 per square foot. The house is heated by a natural gas furnace that is 85% efficient. The cost of natural gas in Wisconsin is $0.82 per therm, and 1 therm is equal to 100,000 Btu (British thermal units). The number of heating degree days for Wisconsin is 7499. We want to find the payback period for the new insulation.

So, breaking down our equation, we have:

Ci = $0.41 per square foot

Ri = 13

Rf = 19

E = 85% = 0.85

Ce = $0.82 per therm = $0.0000082 per Btu

HDD = 7499

P = (0.41 * 13 * 19 * 0.85) / ((0.0000082) * (19 – 13) * 7499 * 24)

P = 9.7 years

Wowza! That’s more time than I was expecting. So what are the key factors here that could cause this to payback period to go down? Well, first of all, with a little more looking, you might be able to find a better price on your insulation than a quick tour through the Home Depot website gave me. Also, natural gas in Wisconsin is pretty dang cheap right now, all things considered. But as more cities and states do things like ban fracking for natural gas, that cost could go up significantly, which would obviously bring the payback period down.

Example 2: Sprayed Foam Insulation – How much can we get?

What if instead of replacing all that R-13 fiberglass insulation with R-19 fiberglass insulation, we wanted to replace it with spray foam insulation?

Spray foam insulation has an R-value per inch of foam thickness. You can increase the total R-value by spraying a thicker layer of foam. There are tons of options available as far as spray foam goes, but for the sake of this example, we will use this Dow Froth Pack as our insulation. This spray foam provides R-6 per inch of thickness, so 1 inch has R-6, 2 inches has R-12, 3 inches has R-18, so on and so forth.

In this example, instead of calculating the payback period for the spray foam insulation, we’re going to see how thick of an insulation layer we can “afford” to apply, given the same payback period as the upgrade from R-13 to R-19 fiberglass. In other words, we are going to solve for Rf.

So, breaking down our equation, we have:

Ci = $1.01 per square foot

Ri = 13

Rf = x

E = 85% = 0.85

Ce = $0.82 per therm = $0.0000082 per Btu

HDD = 7499

P = 9.7 years

Through the magic of algebra, we can rearrange our equation to solve for Rf:

Rf = (P * Ri) – P – ((Ci * Ri * E)/(Ce * HDD * 24))

Which looks gross, but it’s really just a matter of plug and chug at this point:

Rf = (9.7 * 13) – 9.7 – ((1.01 * 13 * 0.85)/(0.82 * 7499 * 24))

Rf = 10.67, or about 1.75 inches thickness of the spray foam insulation.

So, for the same payback period as with the fiberglass insulation, we’d actually be downgrading from R-13 to R-10.67 with the spray foam. If we wanted to increase to the equivalent R-value, our payback period with the spray foam would be nearly twice as long!

But then what’s all the fuss about spray foam insulation? Why would anyone use it if the return on investment is apparently so low? Well, the R-value of the insulation isn’t telling you the whole story here. Remember the walls of your house are not just made out of batts of insulation. There is also the framing, the siding, the sheet rock, and all the other layers to consider. And those layers typically have small cracks and crevices where the heat can leak quite easily. One of the benefits of the spray foam insulation is that it fills in and seals all those leaky spots. So not only do you have the impact of the insulation layer, but you’ve increased the insulation abilities of all those other layers as well. Insulation can be one of those things were whole is greater than the sum of the parts.

Onward, Energy Efficiency Warriors. Next time we visit this topic we’ll get to the big finale: Can you insulate a house enough such that you don’t need a furnace???

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building house

More on Choosing Paint

A couple weeks ago I went through a run down of how to choose and environmentally friendly paint. Now I want to share a bit about what decision we made and how it is working out so far.

For some reason, the small town we bought our house in has about 50 different privately owned auto shop, but the only hardware store in town is a giant Menards. And this Menards carries 2 brands of paint – Dutch Boy and Pittsburgh Paint.

Pittsburgh Paint makes a Low-VOC paint line called “Grand Distinction”. And while the info online says it “contains considerably less VOCs than other leading paints with similar attributes,” they do not seem to actually publish the VOC levels on their website. It probably does say on the can, but *spoiler alert* this was not the paint I chose, so I don’t have the can around to check the levels.

Dutch Boy’s Low-VOC paint line is called “Refresh” and is Greenguard certified as being low in VOCs and low in other air polutents. The base paint contains 50 ppg VOCs. Refresh also claims to reduce household odors with “Arm and Hammer® technology”. But I’m honestly pretty skeptical about that. We’ll see.

low VOC paint

So far we’ve painted our living room and our front room with the Refresh paint, and I’ve been pretty pleased with it. There is very little odor while painting, and the little odor there is fades away very quickly – and I’ve been painting in the winter, so it’s not like I’ve got the windows open to help clear out any odors.

I’ve also been pleased with the coverage thus far. Now we’ve only gone from cream walls to white, but the ceilings took two coats of paint, and for the most part the walls only required one! We’ve got some color plans coming up, as well as painting our wooden cabinets, so I’ll report back on the coverage when I’ve seen how those projects pan out.

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building house living green

Choosing an Environmentally Friendly Paint

Probably one of the easiest and most affordable ways to refresh your space is to slap a coat or two of paint on the walls. However, walking into your local hardware store or big box home improvement store and coming to aisles full of paint cans can be overwhelming. I’m certainly no expert on all the types of paint and what exactly you should choose for your particular application, but I can tell you how to choose an environmentally friendly paint.

choosing an environmentally friendly paint

Oil Based vs. Latex (Water Based)

The first question to address when choosing and environmentally friendly paint is whether to go with an oil based paint or a latex paint.

Oil based paints are slower drying which can provide a smoother finish, as any pools or ridges will have a chance to settle before the paint is completely dry. Oil based paints also can have better coverage, which means fewer coats, and can hold up better over time. However, oil based paints require more harsh chemicals to keep the colors suspended in the paint. Not only do oil based paints require special disposal at a hazardous material collection center because of these harsh chemicals, but they also give off a lot of fumes. These fumes are dangerous to breathe in. Oil paints also require harsh chemical solvents for clean up.

Latex, or water based paint, dries faster, can be fairly easily cleaned with water, and resists yellowing over time (another common issue with oil based paints). Latex paint contains fewer hazardous chemicals than oil based paint, but still contains some and can release harmful fumes. Latex paint should not be dumped down the drain, or just put in the trash in its liquid state, but if it needs to be disposed of, it can be dried up by soaking it up with kitty litter, newspaper, or sawdust.

When given the option between oil or latex paint, the more environmentally friendly paint is latex paint.

Volatile Organic Compounds (VOCs)

The harmful fumes given off by paint are due to volatile organic compounds, or VOCs. VOCs are emitted gases that can cause a variety of health problems when breathed in. VOCs can be found in paints, household cleaners, adhesives, pesticides, and building materials among other things. In paint, the chemicals that make up VOCs are used to hold the dyes suspended in the paint. After the paint is spread, the VOCs evaporate out, and the color stays in the dried paint. The US government has created a standard of 250 grams per liter of VOCs for flat paints and 380 g/l for other finishes. However, California, a state that frequently enacts stricter environmental regulations, has capped VOCs at 50 g/l for all finishes. Paints that adhere to the California regulations typically label themselves as Low-VOC. (It’s important to note that in order for a paint to be labeled low VOC, it only has to contain less than the government standards. You should read the label carefully to see the reported number of VOCs each brand and finish of paint contains.)

More recently some paint brands have advertised certain paint lines as being no VOC. In order to do so, they must contain less than 5 g/l of VOCs. Some paint brands have also opted to get evaluated by third party certification programs such as Greenguard or Green Seal to set themselves apart as environmentally friendly paint choices. These certifications evaluate the paint on more than just VOC levels as well and award their labels to paints that meet their environmental standards.

To choose a more environmentally friendly paint, look for low- or no VOC paint options, or paints that have received Greenguard or Green Seal certification.

 Natural Paints

There are some paint options that do not contain the harsh solvents used in oil or latex paints. These paints are instead pigmented with naturally occurring materials such as clay, lime, linseed oil, or chalk. Natural paints do not contain VOCs, but they do come with drawbacks. The color choices are limited, drying time can be long, coverage can be not great, and they are typically significantly more expensive than latex paint. You can find information on making your own natural paint and a list of natural paints here.

If you want to make the most environmentally friendly paint choice, and your needs can be met by the limitations above, look for natural paints.

 

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Related: Tell Me More About Greenguard Certification

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building energy living green

Happy 2015

Happy 2015Happy 2015!

How’s it feeling now that you’ve had a week to break it in?

Let’s start this year off with a bang: We bought a house!  Due to job related circumstances we will only be living in the house part time between now and June, and we will spend the rest of our time in our current apartment. This will provide us with plenty of time to get some updates and projects done before we move in for good this summer.

Now you might be wondering, what does this house have to do with this little blog? Well, it means that as we do house renovation projects, I’ll have plenty of opportunity to share with you all of those green building home renovation projects, like:

  • What are the most earth friendly paints, stains, and adhesives to use?
  • Which are the most sustainable flooring materials?
  • How do you go from lawn to organic garden (hopefully without your neighbors giving you the side-eye)?

Another blog series that I have in the works is on making a house more energy efficient. I’ll take a look at the energy usage of this house, and similar sized houses in the neighborhood, and do monthly updates on what we have done to bring that energy use down.

Aside from the house, in 2015 I’ll be continuing the series on “green” certifications in the construction and home furnishing areas. I’ll also continue to explore passive house design, integrative design, green living habits, and compost.

If there is anything you’d like to see in the upcoming year, be sure to leave a comment or drop me email.

I know I’m excited for everything that 2015 has to bring! I hope your new year is starting out shiny and bright and not too cold!

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building energy

Adding Insulation for Energy Efficiency Part 1

adding insulation for energy efficiency
“Untitled” by Jesus Rodriguez // CC BY

As we continue to explore the possibility of building a house that doesn’t require a heating and cooling system, the next step is to get to know the current standard for adding insulation for energy efficiency. This is a topic that involves a bit of math. In this post, I’ll walk you through the equations that are used to determine how much insulation to add. In the next post on insulation I’ll go through two simple examples of working out how much insulation to add.

Payback Period

The typical plan for adding insulation for energy efficiency is to add to the point where you are able to cover the costs of the added material with the money that you will be saving in heating and cooling costs. The time it takes to recoup the money for energy efficiency upgrades is called the payback period. For the insulation of a residential building the average payback period that most people are interested in waiting is between 4 and 5 years. So, in order to figure out the payback period we need to consider the R-value of the insulation, and the cost of heating and cooling the house per year.

Calculating the R-Value

As you may remember from my last post on insulation, the R-Value is a numerical value given to insulation that tells you how much the insulation is going to resist the flow of heat. Determining the R-Value of an insulation material depends on a number of different factors:

  • Initial indoor temperature (Ti)
  • Outdoor temperature (To)
  • time (t)
  • surface area of the building (A)
  • The heat loss indoors (dQ)

And the equation looks like this:

R = (Ti – To) * A *t / dQ

The good news about R-Value calculations is that you usually don’t have to do them. Since the measurements to complete the calculation are done in a lab setting in a controlled environment, the insulation manufacturer provides that information for you when you choose your material.

Calculating the Payback Period

In order to calculate the payback period of adding insulation, we need to take into account the insulation and the heat system.  The payback period depends on the following features:

  • R-value of the initial insulation (Ri)
  • R-value of the final insulation (Rf)
  • Cost of insulation (Ci)
  • Efficiency of the heat system (E)
  • Cost of energy (Ce)
  • Number of days that require heat per year (t)

And the equation looks like this:

P = (Ci * Ri * Rf * E) / (Ce * (R2 – R1) * t)

You can find more information on calculating the payback period of adding insulation here.

I know looking at all these equations can be intimidating if you are interested in figuring out how much insulation to add to your house to meet the 4 – 5 year payback period. But hopefully after I work through a couple examples in my next post on insulation, it will seem manageable. Maybe you’ll even be inspired to add insulation to your own house to make it more energy efficient.

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building

Tell me more about Forest Stewardship Council Certification

forest stewardship council certification

Lumber is a pretty integral ingredient to how we build and furnish our homes. And luckily, when properly managed and harvested it is a sustainable and renewable resource. It is also an excellent natural carbon sequestration method. And seeing as how we can’t quite seem to figure out how to do that with technology, it seems like we should probably take advantage of Mother Nature when she does it for us. But you see that bolded sentence up there about managing and harvesting properly? That’s the kicker. How do we ensure that the lumber we are building with is managed and harvested in a sustainable manner? Well, that’s where the Forest Stewardship Council comes in handy.

The Forest Stewardship Council (FSC) is a international not-for-profit organization devoted to responsible management for the world’s forests. It does this primarily through standard setting, certification, and labeling of forest products. The FSC was established in 1953 as a response to concerns about deforestation. It certifies and labels forest products which are harvested in environmentally appropriate ways, are socially beneficial, and economically viable.

How does lumber become FSC labeled

There are two types of certifications that the FSC offers, Forest Management and Chain of Custody. Both certification require evaluation by an independent FSC accredited certifier that the forest of chain of custody meets the principles and criteria that the FSC has developed.

The FSC maintains 10 principles to determine if a Forest can be certified:

  1. Compliance with all applicable laws and treaties, and all FSC principles and criteria.
  2. Tenure and use rights and responsibilities.
  3. Recognition and respect of indigenous peoples rights.
  4. Operations must maintain or enhance the long-term social and economic well being of forest workers and surrounding communities.
  5. Efficient use of products to ensure economic viability, and social and environmental benefits.
  6. Maintain the ecological functions and and integrity of the forest.
  7. A long-term appropriate management plan must be written and followed.
  8. Monitoring and assessment
  9. Maintenance of High Conservation Value forests.
  10. Plantations which are in accordance with principles 1-9

In order for lumber to be labeled by the FSC it must come from a forest which is certified in Forest Management, and it must follow a supply chain which has been certified in Chain of Custody.

What sorts of products are FSC labeled

More than just lumber can be labeled by the FSC. The label can also be used by paper products, furniture, jewelry, and medicines that were made by products in certified forests.

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Want to learn about other environmental, energy, and sustainability certifications? Check out these posts:
LEED certification
Energy Star certification
Green Guard certification

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building energy

Insulation

A couple weeks ago I posted an Autodesk Academy video of my hero, Amory B. Lovins talking about integrative design. In this video Amory talks about insulating a house to the point that a heating and cooling system are no longer needed. I’d like to dive deeper into this idea. To start, let’s talk about some of the basics of insulation.

"Insulation Roll" by Mark Evans // CC BY
“Insulation Roll” by Mark Evans // CC BY

Why we insulate buildings

Here in the northern part of the country we typically think of insulation as necessary for keeping the heat in during the fall and winter (and sometimes spring) months. But the most basic purpose of insulation is to prevent the movement of heat. Both out of and into a structure. Insulation is also quite useful for keeping heat out of a building in the summer. So insulation can cut down on the need for both heating and cooling a building when more extreme temperatures hit. Having a well insulated home can reduce your energy use (and costs!) all year round.

R Values

Insulation materials are rated using an R Value. R value is a measure of resistance to heat flow, and is based on the temperature difference between indoors and outdoors, the area of the insulation, time, and heat loss. High R values provide better insulation than low R values. Now, walls and ceilings and floors are made up of multiple layers of different materials, and to find the total R value of the system, we add together the R value of each individual layer. Oak Ridge National Laboratory put together a recommended R value calculator based on zip code, heat source, and part of the building that is being insulated.

How buildings are typically insulated

If you rip open the drywall in one of your exterior walls chances are you will find fluffy, pink, fiberglass insulation. This is known as batting, or fiberglass batt insulation. Fiberglass batt has an R value of about 3 per inch of thickness.

Because heat rises, in colder climates it is important to have a well insulated roof or attic to keep that heat inside the building. Typically, houses have a blown insulation (loose insulation that is blown into a space to fill it), that can be 15 inches or more in thickness.

In warmer climates , where you want to keep the heat out of the house, sometimes the insulation batt has a shiny metallic side. This is put on the outer face of the wall to help reflect heat away from indoors.

Common Types of Insulation

There are many more types of insulation than the fiberglass batt or blown fiberglass.

Mineral Wool is a material that resembles matted wool, but is man made rather than sheep made. In batt form, its R value is equal to fiberglass batt, but as a blown insulation it has a larger insulation, making it slightly better for attic spaces.

Cellulose is a material made from plant fiber that can be used as a blown insulation. It also has a slightly higher R value than blown fiberglass. Cellulose can also be mixed with water, adhesive, and moisture retardant and used as a spray insulation, which has the advantage of being better able to get into nooks and crannies to seal up a space. Cellulose also has the benefit of being a vapor barrier, preventing the buildup of moisture, which can help prevent rot.

Foam board insulation can be made from polystyrene or polyurethane among other polys. The boards are made of dense foam that can be cut to fit into wall spaces, and provides a good amount of insulation for a small amount of thickness.

Foam spray insulation may be made from a variety of different man made materials such as polyurethane, and is sprayed into the walls and ceilings. Foam insulation is excellent at sealing up walls or ceilings that have small cracks and/or holes, however it is much more expensive than fiberglass insulation.

So, now we have a base understanding of insulation, next time we can talk about insulating for greater energy efficiency.

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Want to read more about insulation? Here are some good sources:
Energy.gov articles on Insulation
Insulation R Value Chart

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building design

Tell me more about Greenguard Certification

It seems these days that every packaged product has some symbol boasting its quality. But not every seal or certification is created or bestowed equally. The marks of a meaningful certification program are high standards, rigorous third party testing, and ongoing off-the-shelf evaluation. It also helps if the certifying body is not-for-profit.

Greenguard is a third party certification that is used for indoor air quality. It was started by the Greenguard Environmental Institute in 2001, and was acquired by UL Environment in 2011. The certification is for indoor use products that produce low emission amounts of volatile organic compounds (VOCs).

There are a couple different types of Greenguard certification that a product can receive. The Greenguard Certification is for indoor use products that meet strict chemical emissions limits and are suitable for use in a healthy indoor air quality environment. Greenguard Gold Certification is a stricter certification specifically for sensitive individuals such as children and seniors. The products that are certified as Greenguard Gold are appropriate for use in schools, childcare facilities and healthcare facilities.

How does a product become Greenguard certified

A product manufacturer applies for product certification. The product is evaluated and tested to make sure it meets the Greenguard standards for certification. The standards are set based on criteria set by key public health agencies. If a product is certified, it is then subject to annual testing for more than 10,000 different VOCs.

What sorts of products are Greenguard certified

Over 10,000 products from 350 different manufacturers currently carry the Greenguard seal. There is a wide variety of products that have received Greenguard certification, including paint, adhesives and sealants, building materials, furniture, electronics and textiles. If you are looking for specific products that have received Greenguard certification, you can look here.

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Interested in learning about other environmental certifications? Check out these posts on LEED certification and Energy Star.

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building design energy

Amory B. Lovins on Integrative Design

I’m going to give you a little bit of homework before we get into the meat of this post. Watch this video:

(I’ve probably posted that before. I’m a wee bit obsessed with Mr. Lovins and his work)

Now let’s talk a little bit about integrative design. Integrative Design is a method of design based on working from the top down. Basically you look at the entire system – the entire car, the entire house, the entire factory, with the intention to make it as energy efficient as possible. By looking at design from the top down you ask how to make the best holistic design by intertwining the functions of the different components.

Integrative Design is different from traditional design methods which focus on optimizing each individual piece of the system and then fitting them together and adjusting how they interact. This traditional method creates the most optimized walls and plumbing and HVAC. But the integrative design approach allows you to say, what if we didn’t need the HVAC at all  (or at least not our idea of the most optimized HVAC) because we change the way we build the walls completely.

At the end of the Autodesk video Amory mentions the 10xE principles of integrative design, and I want to share those here:

  1. Define shared and aggressive goals.
  2. Collaborate across disciplines.
  3. Design non-linearly.
  4. Reward desired outcomes
  5. Define the end-use.
  6. Seek systemic causes and ultimate purposes.
  7. Optimize over time and space.
  8. Establish baseline parametric values.
  9. Establish the minimum energy or resource theoretically required, then identify and minimize constraints to achieving that minimum in practice.
  10. Start with a clean sheet.
  11. Use measured data and explicit analysis, not assumptions and rules.
  12. Start downstream.
  13. Seek radical simplicity.
  14. Tunnel through the cost barrier.
  15. Wring multiple benefits from single expenditures.
  16. Meet minimized peak demand; optimize over integrated demand
  17. Include feedback in the design.

In Amory’s lecture he talks about using integrative desing in building design for heating and cooling, in auto design for using less fuel, and in factory design for pumping fluid. Stay tuned for a bit of a deeper dive into these topics in the future, including how the integrative design principles lead to radically different approaches in each of these categories.

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building energy

Tell Me More About Energy Star

Chances are you’re familiar with the blue and white logo that can be found on many types of home appliances, but do you know what being Energy Star certified actually means?

The Energy Star program was started by the Environmental Protection Agency and the Department of Energy in 1992 as a labeling program for energy efficient appliances. Energy Star is now an international standard for energy efficiency. The Energy Star label can now be applied to computers, servers, appliances, heating and cooling systems, home electronics, imaging equipment, lighting, and new homes and buildings.

In 2010 it came to light that the Energy Star label was being wrongly granted and misused. It was being granted to products that did not exist, and if a company had one product certified they were able to download the label and put it their other, non-certified products as well. Since then, a number of critical audits were completed, and the Energy Star label and certification process has been revamped to prevent these sorts of fraudulent claims.

Now each application is reviewed for approval. Products must be third-party tested in EPA approved labs. Additionally, each year off-the-shelf tests are conducted on a percentage of Energy Star labeled products to ensure that the consumer is receiving products that meet the standards.

So what does it mean if something has and Energy Star label

Each product has a set of standards that it has to meet in order to receive the label. For example, a refrigerator must save 20% of energy based on the industry minimum standard, an air conditioner must save 10%, and a light bulb must save 75% vs a standard incandescent. These standards are updated every couple years or so, in particular when at least 50% of the market is held by energy star labeled products.

The Energy Star label and buildings

There are currently Energy Star ratings for new homes, commercial spaces, and industrial plants. Buildings are evaluated for the energy efficiency of their heating and cooling systems, water management, and air quality. Buildings are evaluated by professional engineers or registered architects and have to receive a rating of 75 or higher (out of 100) in order to receive an Energy Star label.