Building on LEED
Improving the evaluation of ‘green bulidings’
Erika Larsen
Kathryn King
Likwan Cheng
Alp Esener
Residential and commercial buildings are key
contributors to energy use and environmental damage
Buildings are a key source of US energy use
•
5 Billion gallons of potable water are used to flush toilets.
•
Typical jobsite creates 2.5 pounds/sf of solid waste.
•
20% of fresh water species faced extinction over the last several
decades.
Sourced from: www.dcp.ufl.edu/ckibert/Lectures/LEED_Intro_Spring04_042704.ppt and
http://dls.state.va.us/groups/HousingCommission/Documents/2007documents/GreenBldg.pdf
LEED point system was develop to add greater
transparency and structure
Background
•
LEED: Leadership in Energy and Environmental Design
•
•
A point based site/design/construction certification system
Designed by US Green Building Council (USGBC) in 1998
Goals
•
Intended to be a “whole building approach” to take into account
interactions in energy use/emissions within the building design
•
Define “green” by providing a standard for measurement
•
Prevent “greenwashing” (false or exaggerated claims)
•
Stimulate green competition
•
Reduce building’s impacts on the Environment
•
Raise consumer awareness
LEED is a “menu-driven” system with 6 categories and
69 possible points
Category
Purpose
Points possible
Sustainable Sites
Reduce environmental damage
by encouraging more
sustainable means of transport
1 prerequisite 14
possible points
Water Efficiency
Encourage more efficient use
of water and waste treatment
5 possible points
Optimize energy use by
encouraging more green and
on-site renewable energy
Encourage reductions in
emissions and refrigerants
3 prerequisites
17 possible
points
Materials and
resources
Encourages use of sustainable
and environmentally friendly
materials in construction and
renovation.
1 prerequisite
13 possible
points
Indoor
Environmental
Quality
Encourage standards and
products that reduce health
risks to occupants
2 prerequisites
15 possible
points
Innovation and
Design
Incentivize adherence to LEED
design code, e.g., including
LEED certified member in
process
5 possible points
Energy and
Atmosphere
LEED
Certification
Type
Min-Max
Points
Certified
26-32
Silver
33-38
Gold
39-51
Platinum
52-60
There are several benefits of the LEED model
Overall
(across
building
types)
•
Economic
•
•
•
Health &
Safety
•
•
•
Initial premium is estimated under 5%, less with proper
education
In one case study, market value increased $4 for every $1
invested in green improvements
In another case study, waste management and cleaning costs
decreased from $1.87 to $1.16/sq. ft
Also linked to retail sales and workplace productivity increases
(2-16%)
People on average spend 90% of time indoors
Contaminants indoors can be 2 to 5x worse than outdoors
Sickness as a result of improper cleaning estimated to cause
more than $60-400 bn annually in productivity losses
Sourced from: http://www.rose-hulman.edu/users/groups/Facilities/HTML/departments/custodial/Sustainability-01-
As a result, LEED projects and USGBC memberships
have steadily increased
LEED Projects have increased
steadily across all type of
buildings
And USGBC membership growth has
reflected this expansion
Sourced from: http://dls.state.va.us/groups/HousingCommission/Documents/2007documents/GreenBldg.pdf
Current Critiques of LEED 2.2
Inequitable points:
•The LEED point system awards 1 point for
most project items.
•Does not weigh more cost-effective or
energy efficient schemes more heavily.
Administrative drawbacks:
•Can take up to 300 days to become certified.
•Documentation can take up to 225 hours to
fully complete and be verified.
LEED was
initially
designed to be
a helpful tool,
not a mandate
LEED 3.0
• A new version has been released for
public comment.
• Our project will evaluate the energy
and atmosphere section looking at :
• Point distribution
• Labs
LEED 3.0
Energy and Atmosphere
LEED 2.2
LEED 3.0
Energy Section is 24% of total
points
Energy section is 35% of total
points
Minimum Energy Performance
14%
Minimum Energy Performance
10%
Need to increase energy
performance by 3.5% to
receive additional points
Need to increase energy
performance by 4.0 % to
receive additional points
LEED 2.2
Energy and Atmosphere
Percent Energy Savings =
100 x
Performance Baseline – Predicted Performance
–––––––––––––––––––––––––––
Performance Baseline
LEED 2.2
Energy and Atmosphere
LEED 2.2
Energy and Atmosphere
LCC Method
•
•
What fuel do you use to heat your home?
Calculate costs based
What Census region do you live in?
region, type of fuel used, How large is your home? (in square feet)
When was your home built?
over the life of the product.When was your existing furnace installed?
Gas
Gas Rate ($/therm)
Discount by a 4% rate.
$1.17
CHICAGO, IL
2,500
New Unit
Select 'New Unit' to compare new furnace options
New ENERGY STAR Qualified
Unit
Installed Cost per Unit (estimated retail price)
$1,100
Annual Fuel Utilization Efficiency (AFUE)
Use with programmable Thermostat (Yes/No)
Include only heated space
1990-1999
90%
Conventional or Existing
Unit
$780
78%
Yes
No
Thermostat Usage Guidelines
You have selected the programmable thermostate option, your savings are
calculated based on ENERGY STAR suggested thermostat usage shown in the link
above, your actual savings may vary.
Annual and Life Cycle Costs and Savings for a Gas Furnace
ENERGY STAR Qualified Unit
Conventional Unit
Savings with ENERGY
STAR
*
Annual Operating Costs
Energy cost
• Calculate the savings on
an energy efficient
product compared to
a conventional product.
$743
$1,051
$308
Energy Consumption (MMBTU)
63
90
26
Energy Consumption (Therms)
634
897
263
Maintenance cost
$0
$743
Total
$0
$1,051
$0
$308
Life Cycle Costs*
Operating costs (energy and maintenance)
Energy costs
Maintenance costs
Purchase price
Total
$9,401
$13,306
$3,905
$9,401
$13,306
$3,905
$0
$1,100
$10,501
$0
$0
$780
$14,086
Simple payback of initial additional cost (years)
-$320
$3,585
†
* Annual costs exclude the initial purchase price. All costs, except initial cost, are discounted over the products' lifetime using a real discount rate of 4%. See "Assumptions"
to change factors including the discount rate.
†
Sourced from : Energy Star Savings Calculator
A simple payback period of zero years means that the payback is immediate.
1.0
LCC comparison
Summary of Benefits for 1 Programmable Thermostat(s)
• Two products
that are both designed
to provide an 18%
energy efficiency.
Initial cost difference
Life cycle savings
Net life cycle savings (life cycle savings - additional cost)
Life cycle energy saved (MBTU)-includes both Heating and Cooling
Simple payback of additional cost (years)
Life cycle air pollution reduction (lbs of CO
2)
Air pollution reduction equivalence (number of cars removed from the road for a year)
Air pollution reduction equivalence (acres of forest)
Savings as a percent of retail price
$19
$2,519
$2,500
236
0.1
30,297
3
4
2718%
Summary of Benefits for a Gas Furnace
• However have very
different economic
impacts.
Initial cost difference
Life cycle savings
Net life cycle savings (life cycle savings - additional cost)
Simple payback of additional cost (years)
Life cycle energy saved (MMBtu)
Life cycle air pollution reduction (lbs of CO
2)
Air pollution reduction equivalence (number of cars removed from the road for a year)
Air pollution reduction equivalence (acres of forest)
Savings as a percent of retail price
Sourced from : Energy Star Savings Calculator
$320
$3,905
$3,585
1.0
474
55,456
5
7
326%
LCA Method
• The LCA method
is calculated by
looking at the all
necessary inputs
during the life of
a product.
• This number can is
calculated by different
software such as BEES
TRACI or GABI.
• The software is able to
trace out different areas
of interest such as energy
input or GHG emissions
over the life of the product.
Sourced from : BEES software. NOTE: A lower score is better
LCA Case study: PV solar panel
• The energy
used during the
life cycle of the
BOS is not
included in the
current
LEED point
structure.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Sourced from : GABI software
LCA Case Study: PC solar system
•The GHG emission
created during the
life cycle of the
BOS is not
included in the
current
LEED point
structure.
Sourced from : BEES software
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
LCA LEED point
• The most sustainable
LEED point system would
weight according to the
LCC
(economic Impact)
and the
LCA
(environmental impact)
Sourced from : BEES software
Costs and Benefits of LCC and LCA
Costs
Benefits
Complexity
Accurate Environmental
Impact
Building Data Bases
Fully Sustainable
Approach
Training
LEED For Laboratory Buildings?
Electricity Usage by
Building Types (kWh/sf)
85
16
buildings –
–Energy intensive
–More complex
–Greater variability in
operation schedules
School
Office
LEED-Application
Lab
14
Laboratory
Guide for
Laboratories…under
development.
Savings-Based LEED Point Allocation: Lab Fume Hood
Energy Use as Function of Sash
Position and Fan Power
Energy Savings
Measures
Automatic
Sash
Controller
Variable Air
Volume
System
Settings (Sash Height; Fan
Power)
6 to 0.25 in
1.8 W/cfm
1.8 to 0.8 W/cfm
6 in
Annual Energy Savings
5,765 kBtu
2,263 kBtu
1
0.4
Present Value of Life-Time
Cost Savings (15 years; 5%)
$10,065
$1,839
Net Benefits
$8,565
$839
1
0.1
72 MBtu
0
Present Value of LT Carbon
Cost Savings (15 years; 5%)
$350
0
Net Benefits + Carbon Cost
Savings
$8,915
$839
LEED Points Based on LT
Net Benefits + Carbon
Cost Savings
1
0.1
LEED Points Based on
Annual Energy Savings
LEED Points Based on LT
Net Benefits
Fuel Savings
Based on LNBL Model
QUESTIONS?
