Our hard work as finally paid off... and it's too big to fit on this blog! So we've created a website devoted solely to our May T. Watts Appreciation Society Embodied Energy Calculator!
The calculators are located at www.thegreenestbuilding.org - check 'em out and let us know what you think. You can figure embodied energy, demolition energy, compare embodied energy to gallons of gas, and even do a complete teardown calculation. With help from MJ, we think we've put together a great site for preservationists to visit. We hope you all find it useful.
We've also now posted the ACHP report discussed earlier on The Greenest Building site for download. So get it and get working!
We'll keep tweaking the page, adding more calculators, and are working on a survey model calculator. If anyone wants to donate graphic design experience, that could probably help us a ton.
The greenest building is calculated.
Showing posts with label embodied energy. Show all posts
Showing posts with label embodied energy. Show all posts
Saturday, January 19, 2008
Monday, January 7, 2008
more on embodied energy
Back after a while... we've been working on some big things, so stay tuned! For now, a plug:
We really like the site Your Home Technical Manual, sponsored by the Australian government.
We're asked to build "long life, durable and adaptable buildings." Historic homes win on all three! They've obviously had a long life, they're durable, and as anyone who lives in an old home will tell you, are easily adaptable!
Below are excerpts from the site. Visit and click around, there is a lot of great info.
------------------------------
Embodied energy is the energy consumed by all of the processes associated with the production of a building, from the acquisition of natural resources to product delivery. This includes the mining and manufacturing of materials and equipment, the transport of the materials and the administrative functions. Embodied energy is a significant component of the lifecycle impact of a home. Every building is a complex combination of many processed materials, each of which contributes to the building's total embodied energy. Renovation and maintenance also add to the embodied energy over a building's life.
It was thought until recently that the embodied energy content of a building was small compared to the energy used in operating the building over its life. Most effort was therefore put into reducing operating energy by improving the energy efficiency of the building envelope. Research has shown that this is not always the case. Embodied energy can be the equivalent of many years of operational energy.
The materials we use to build our homes have many "unseen" adverse environmental impacts.
The importance of embodied energy and other environmental impacts does not become apparent until we examine the materials from a life cycle approach, usually known as Life Cycle Assessment (LCA). LCA examines the total environmental impact of a material or product through every step of its life - from obtaining raw materials (for example, through mining or logging) all the way through manufacture, transport to a store, using it in the home and disposal or recycling. LCA can consider a range of environmental impacts such as resource depletion, energy and water use, greenhouse emissions, waste generation and so on.
Choices of materials and construction methods can significantly change the amount of energy embodied in the structure of a building. True low energy building design will consider this important aspect and take a broader life cycle approach to energy assessment. Merely looking at the energy used to operate the building is not really acceptable. Operational energy consumption is dependent on the occupants. Embodied energy is not occupant dependent - the energy is built into the materials. Embodied energy content is incurred once (apart from maintenance and renovation) whereas operational energy accumulates over time and can be influenced throughout the life of the building.
Research by CSIRO has found that the average household contains about 1,000 GJ of energy embodied in the materials used in its construction. This is equivalent to about 15 years of operational energy use. For a house that lasts 100 years this is over 10 percent of the energy used in its life.
As the energy efficiency of houses and appliances increases, embodied energy will become increasingly important. Reuse of building materials commonly saves about 95% of embodied energy that would otherwise be wasted.
Try to follow these guidelines:
Design for long life and adaptability, using durable low maintenance materials.
Ensure materials can be easily separated.
Avoid building a bigger house than you need. This will save materials.
Modify or refurbish instead of demolishing or adding.
Ensure materials from demolition of existing buildings, and construction wastes are re-used or recycled.
Use locally sourced materials (including materials salvaged on site) to reduce transport.
Select low embodied energy materials (which may include materials with a high recycled content) preferably based on supplier-specific data.
Avoid wasteful material use.
Specify standard sizes, don't use energy-intensive materials as fillers.
Ensure off-cuts are recycled and avoid redundant structure, etc. Some very energy intensive finishes, such as paints, often have high wastage levels.
Select materials that can be re-used or recycled easily at the end of their lives using existing recycling systems.
Give preference to materials manufactured using renewable energy sources.
Use efficient building envelope design and fittings to minimise materials (eg. an energy efficient building envelope can downsize or eliminate the need for heaters and coolers, water-efficient taps allow downsizing of water pipes, etc).
Ask suppliers for information on their products and share this information.
http://www.greenhouse.gov.au/yourhome/technical/fs31.htm
We really like the site Your Home Technical Manual, sponsored by the Australian government.
We're asked to build "long life, durable and adaptable buildings." Historic homes win on all three! They've obviously had a long life, they're durable, and as anyone who lives in an old home will tell you, are easily adaptable!
Below are excerpts from the site. Visit and click around, there is a lot of great info.
------------------------------
Embodied energy is the energy consumed by all of the processes associated with the production of a building, from the acquisition of natural resources to product delivery. This includes the mining and manufacturing of materials and equipment, the transport of the materials and the administrative functions. Embodied energy is a significant component of the lifecycle impact of a home. Every building is a complex combination of many processed materials, each of which contributes to the building's total embodied energy. Renovation and maintenance also add to the embodied energy over a building's life.
It was thought until recently that the embodied energy content of a building was small compared to the energy used in operating the building over its life. Most effort was therefore put into reducing operating energy by improving the energy efficiency of the building envelope. Research has shown that this is not always the case. Embodied energy can be the equivalent of many years of operational energy.
The materials we use to build our homes have many "unseen" adverse environmental impacts.
The importance of embodied energy and other environmental impacts does not become apparent until we examine the materials from a life cycle approach, usually known as Life Cycle Assessment (LCA). LCA examines the total environmental impact of a material or product through every step of its life - from obtaining raw materials (for example, through mining or logging) all the way through manufacture, transport to a store, using it in the home and disposal or recycling. LCA can consider a range of environmental impacts such as resource depletion, energy and water use, greenhouse emissions, waste generation and so on.
Choices of materials and construction methods can significantly change the amount of energy embodied in the structure of a building. True low energy building design will consider this important aspect and take a broader life cycle approach to energy assessment. Merely looking at the energy used to operate the building is not really acceptable. Operational energy consumption is dependent on the occupants. Embodied energy is not occupant dependent - the energy is built into the materials. Embodied energy content is incurred once (apart from maintenance and renovation) whereas operational energy accumulates over time and can be influenced throughout the life of the building.
Research by CSIRO has found that the average household contains about 1,000 GJ of energy embodied in the materials used in its construction. This is equivalent to about 15 years of operational energy use. For a house that lasts 100 years this is over 10 percent of the energy used in its life.
As the energy efficiency of houses and appliances increases, embodied energy will become increasingly important. Reuse of building materials commonly saves about 95% of embodied energy that would otherwise be wasted.
Try to follow these guidelines:
Design for long life and adaptability, using durable low maintenance materials.
Ensure materials can be easily separated.
Avoid building a bigger house than you need. This will save materials.
Modify or refurbish instead of demolishing or adding.
Ensure materials from demolition of existing buildings, and construction wastes are re-used or recycled.
Use locally sourced materials (including materials salvaged on site) to reduce transport.
Select low embodied energy materials (which may include materials with a high recycled content) preferably based on supplier-specific data.
Avoid wasteful material use.
Specify standard sizes, don't use energy-intensive materials as fillers.
Ensure off-cuts are recycled and avoid redundant structure, etc. Some very energy intensive finishes, such as paints, often have high wastage levels.
Select materials that can be re-used or recycled easily at the end of their lives using existing recycling systems.
Give preference to materials manufactured using renewable energy sources.
Use efficient building envelope design and fittings to minimise materials (eg. an energy efficient building envelope can downsize or eliminate the need for heaters and coolers, water-efficient taps allow downsizing of water pipes, etc).
Ask suppliers for information on their products and share this information.
http://www.greenhouse.gov.au/yourhome/technical/fs31.htm
Wednesday, December 5, 2007
Concept Model of Demolition Energy for Existing Buildings
We have our embodied energy model down pat. But when we're looking at teardowns, that's only half the equation. The ACHP report also provides a concept model for demolition energy, or "the amount of energy needed to raze, load, and haul away construction materials."*
The concept model provides a second table for demolition energy. The math is simple. Demolition Energy = Gross s.f. multiplied by the demolition energy of materials per s.f. of construction for buildings of similar size and construction type in table 2.
TABLE 2 Demolition Energy of Construction Materials for Existing Buildings
Small Building Size (5000-15000 s.f.)
Construction Type:
Light (e.g. wood frame)............3100 BTU/s.f.
Medium (e.g. steel frame)..........9300
Heavy (e.g. masonry, concrete)...15,500
Medium Building Size (50,000-150,000 s.f.)
Construction Type:
Light (e.g. wood frame)............2400 BTU/s.f.
Medium (e.g. steel frame)..........7200
Heavy (e.g. masonry, concrete)...12,000
Large Building Size (500,000-1,500,000 s.f.)
Construction Type:
Light (e.g. wood frame)............2100 BTU/s.f.
Medium (e.g. steel frame)..........3600
Heavy (e.g. masonry, concrete)...10,500
Now, many (most) homes don't even register on the "small" scale above. But seeing as how demo energy decreases as a building size increases, we think we're being conservative by using numbers meant for 5000-15,000 s.f. buildings to calculate the demo energy of an typical single family home. In other words, the actual energy expended is probably higher.
So, back to our "model" home: 3000 s.f. frame house X 3100 BTU = 9,300,000 BTU. If the same home was made of brick, we're looking at 46,500,000 BTU. Add that to the existing embodied energy, and you're on your way to making a solid case for preserving homes from an energy conservation perspective.
* You are a NTHP Forum member, right? You should be. The journal is great and members can pick up the ACHP report on embodied energy in the pdf file cabinet. Go now!
The concept model provides a second table for demolition energy. The math is simple. Demolition Energy = Gross s.f. multiplied by the demolition energy of materials per s.f. of construction for buildings of similar size and construction type in table 2.
TABLE 2 Demolition Energy of Construction Materials for Existing Buildings
Small Building Size (5000-15000 s.f.)
Construction Type:
Light (e.g. wood frame)............3100 BTU/s.f.
Medium (e.g. steel frame)..........9300
Heavy (e.g. masonry, concrete)...15,500
Medium Building Size (50,000-150,000 s.f.)
Construction Type:
Light (e.g. wood frame)............2400 BTU/s.f.
Medium (e.g. steel frame)..........7200
Heavy (e.g. masonry, concrete)...12,000
Large Building Size (500,000-1,500,000 s.f.)
Construction Type:
Light (e.g. wood frame)............2100 BTU/s.f.
Medium (e.g. steel frame)..........3600
Heavy (e.g. masonry, concrete)...10,500
Now, many (most) homes don't even register on the "small" scale above. But seeing as how demo energy decreases as a building size increases, we think we're being conservative by using numbers meant for 5000-15,000 s.f. buildings to calculate the demo energy of an typical single family home. In other words, the actual energy expended is probably higher.
So, back to our "model" home: 3000 s.f. frame house X 3100 BTU = 9,300,000 BTU. If the same home was made of brick, we're looking at 46,500,000 BTU. Add that to the existing embodied energy, and you're on your way to making a solid case for preserving homes from an energy conservation perspective.
* You are a NTHP Forum member, right? You should be. The journal is great and members can pick up the ACHP report on embodied energy in the pdf file cabinet. Go now!
Thursday, November 29, 2007
embodied energy math
We looked at the embodied energy of one building. But what about a group of buildings, say, the number of wrecking permits reviewed by a North Shore HPC in 2006. Last year this HPC reviewed 85 permits. Taken together, these account for 204,920 s.f. of single family demo. That's equal to a whopping 143,444,000,000 BTUs of embodied energy. We go back to our favorite energy converter, converted our BTUs to gallons of gas, and the results are in. Envelope please...
1,148,614 gallons of gas. And at $3 a gallon the embodied energy is--or rather, in this case, was--worth $3,445,842.
Now lets get creative. Say we used our 1,148,614 gallons to fill up. We'll use the NHTSA's CAFE standards, a combined 22.2 for passenger cars and light trucks (that includes SUVs under 8,500 pounds).* 1,148,614 gallons multiplied by 22.2 miles per gallon gives us 25,499,230.8 miles. For a single vehicle, that's about 1,024 trips around the earth's equator. Whew.
Then we checked out the EPA's Personal Emissions Calculator. If we drove those 25,499,230.8 miles in a year in a vehicle with 22.2 mpg, we'd create 23,669,142 pounds of carbon dioxide. Well, we can't possibly drive 25+ million miles in a single year. The same EPA site tells us 12,100 pounds is average per vehicle per year. So divide 23,669,142 of carbon dioxide by the 12,100 pound average and... yes, it's like putting 1,956 cars on the road. That's a year's worth of demo in one town folks.
So why is embodied energy important? The greenest building does the math.
* and these are "standards," mind you, not actual on the road fuel economy numbers!
Wednesday, November 28, 2007
Concept Model of Embodied Energy Investment in Existing Buildings
So here's the first model presented in the ACHP report mentioned below. Quick and easy, it will give you a simple figure to build from. All you need to know to get started is the building type and size in square feet to figure how much energy, in MBTU, is embodied in that building.
Procedure: multiply the s.f. by the energy investment shown below in table 1 to = embodied energy.
TABLE 1 Embodied Energy of Materials and Construction Per Square Foot of Construction
Residential – Single Family......700 MBTU/s.f.
Residential – 2-4 Family.........630
Residential – Garden Apartment...650
Residential – High Rise..........740
Hotel/Motel.....................1130
Dormitories.....................1430
Industrial Buildings.............970
Office Buildings................1640
Warehouses.......................560
Garages/Service Stations.........770
Stores/Restaurants...............940
Religious Buildings.............1260
Educational.....................1390
Hospital Buildings..............1720
Other Nonfarm Buildings.........1450
a. Amusement, Social & Rec......1380
b. Misc Nonresidential Bldg.....1100
c. Laboratories.................2070
d. Libraries, Museums, etc......1740
so an example is always helpful: 3000 s.f Single Family home X 700 MBTU/s.f = 2,100,000 MBTU of embodied energy.
Wow! It's in the millions?! But what's a BTU? It's a British Thermal Unit.* And 1 MBTU is equal to 1,000 BTU. That gives us 2.1 billion BTU, or 2.1 million multiplied by 1000. Is that a lot of energy? You bet it is. But how can we make sense of it?
Here's an idea. Go find yourself an online converter, or look up some tables if you're the do-the-math-myself type of person. We like OnlineConversion.com's energy page. Type in your BTUs (remember, multiply your MBTU from the ACHP equation by 1000) and choose something we all can understand, say, gallons of gas. Our 3000 s.f. home, at 2,100,000,000 BTU of embodied energy, is equivalent to 16,815.54 gallons of gas. Whoa! Now we're getting somewhere... what about another number most of us are familiar with, kilowatts? That 3000 s.f. building represents 615,449.309 kilowatt hours. This DOE report here says the average midwest household used 9206 kWh a year. The math is easy: 615,449.309 divided by 9206 = over 66 years of electricity use!
If all of this sounds like a lot, well, it is. To put it in dollars and cents, going back to our 16,815.54 gallons of gas, at $3/gal, you're sitting on $50,446.62. That's the investment locked inside 3000 s.f. of home. Would you throw $50,000+ in the landfill? If you're the sort, let the May T. Watts Appreciation Society know immediately. We have landscapes to save.
The greenest building respects its embodied energy!
* a single BTU is the amount of heat required to increase the temperature of a pint of water (which weighs exactly 16 ounces) by one degree Fahrenheit. We read that here.
Procedure: multiply the s.f. by the energy investment shown below in table 1 to = embodied energy.
TABLE 1 Embodied Energy of Materials and Construction Per Square Foot of Construction
Residential – Single Family......700 MBTU/s.f.
Residential – 2-4 Family.........630
Residential – Garden Apartment...650
Residential – High Rise..........740
Hotel/Motel.....................1130
Dormitories.....................1430
Industrial Buildings.............970
Office Buildings................1640
Warehouses.......................560
Garages/Service Stations.........770
Stores/Restaurants...............940
Religious Buildings.............1260
Educational.....................1390
Hospital Buildings..............1720
Other Nonfarm Buildings.........1450
a. Amusement, Social & Rec......1380
b. Misc Nonresidential Bldg.....1100
c. Laboratories.................2070
d. Libraries, Museums, etc......1740
so an example is always helpful: 3000 s.f Single Family home X 700 MBTU/s.f = 2,100,000 MBTU of embodied energy.
Wow! It's in the millions?! But what's a BTU? It's a British Thermal Unit.* And 1 MBTU is equal to 1,000 BTU. That gives us 2.1 billion BTU, or 2.1 million multiplied by 1000. Is that a lot of energy? You bet it is. But how can we make sense of it?
Here's an idea. Go find yourself an online converter, or look up some tables if you're the do-the-math-myself type of person. We like OnlineConversion.com's energy page. Type in your BTUs (remember, multiply your MBTU from the ACHP equation by 1000) and choose something we all can understand, say, gallons of gas. Our 3000 s.f. home, at 2,100,000,000 BTU of embodied energy, is equivalent to 16,815.54 gallons of gas. Whoa! Now we're getting somewhere... what about another number most of us are familiar with, kilowatts? That 3000 s.f. building represents 615,449.309 kilowatt hours. This DOE report here says the average midwest household used 9206 kWh a year. The math is easy: 615,449.309 divided by 9206 = over 66 years of electricity use!
If all of this sounds like a lot, well, it is. To put it in dollars and cents, going back to our 16,815.54 gallons of gas, at $3/gal, you're sitting on $50,446.62. That's the investment locked inside 3000 s.f. of home. Would you throw $50,000+ in the landfill? If you're the sort, let the May T. Watts Appreciation Society know immediately. We have landscapes to save.
The greenest building respects its embodied energy!
* a single BTU is the amount of heat required to increase the temperature of a pint of water (which weighs exactly 16 ounces) by one degree Fahrenheit. We read that here.
Friday, November 16, 2007
counting bricks
So all your preservation buddies are talking "embodied energy" again (they've been at it since the 70s, but it just wasn't cool for the last 20 years)... and you've been fed nothing but LEED-driven developer drivel and need to get hip. So check it out: Mike Jackson at the 2007 NTHP Conference in St. Paul. Mr. Jackson isn't afraid of blasting the consumer approach to green that many have found success in promoting. We think he has a great point, one that preservation takes to heart: how can you buy your way to green? And as he likes to say, preservation isn't recycling, it's REUSE. No need to repackage, resell, and re-whateverelseitisyou'retryingtodo. It's just smart. Like Mike.
So check out his presentation. Embodied Energy is a fairly intuitive concept, if you stop to think about it. Basically (very basically), it's the idea that the building materials in our existing structures represent a considerable investment in energy. And why waste that investment by tearing down historic buildings. There are some great tools out there to figure our how much energy your old house is worth, and we'll post them later.
We won't even try to hide it: the MTWAS loves Mike Jackson, thinks he's brilliant, and are damn happy he works for the IHPA. The NTHP Conference was great too, so a big hello to everyone we met there. The Trust was nice enough to put up a ton of handouts, so check out more stuff here, including something from another favorite, Carl Elefante.
So check out his presentation. Embodied Energy is a fairly intuitive concept, if you stop to think about it. Basically (very basically), it's the idea that the building materials in our existing structures represent a considerable investment in energy. And why waste that investment by tearing down historic buildings. There are some great tools out there to figure our how much energy your old house is worth, and we'll post them later.
We won't even try to hide it: the MTWAS loves Mike Jackson, thinks he's brilliant, and are damn happy he works for the IHPA. The NTHP Conference was great too, so a big hello to everyone we met there. The Trust was nice enough to put up a ton of handouts, so check out more stuff here, including something from another favorite, Carl Elefante.
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