Habitat for Humanity

							 Habitat for Humanity

Energy Efficiency Team



                Sponsor Contact:

               Doug Taylor
            Habitat for Humanity
             420 S. First Street
                 423-4590


  Jeff Bryles             bryles@purdue.edu


  Asli Kumcu              kumcu@purdue.edu


  Brent Phillips          bphillip@ecn.purdue.edu


  Adam Stanczak           stanczak@ecn.purdue.edu


  Drew Susott             dewsott@ecn.purdue.edu



                   October 4, 1999
Executive Summary

International Habitat for Humanity works to provide quality, affordable homes to
families. The final cost of the home is based upon the actual materials and the efficiency
of the techniques used in construction. In order to reduce the final cost of the home, the
Energy Efficiency Team is conducting energy-utilization analyses of current house plans
and materials. The final result will be to recommend energy-efficiency construction
materials and techniques based on these analyses.

Each home design will have a base-line analysis associated with it; the approximate
energy cost breakdown will be calculated so that the homeowner will have an estimate on
what their monthly energy bills will be. Thus far, one two bedroom, one four bedroom,
and one three bedroom homes have been analyzed with monthly cost outputs.

Also, for each home design, the approximate energy cost breakdown is calculated so
future homeowners will know what to expect when they are planning to buy a home.
Progress on this project involved the following five steps:
        Identification of the method for performing energy analysis of Habitat homes
        Gathering specific home design
        Identification of different energy saving techniques and materials and their
       associated initial costs
        Modeling of the baseline and modified home designs
        Analysis of the results and recommendations for design changes

More homes will be analyzed as the Architecture team models them. The energy
efficiency team will also be looking at factors, which may be changed to make current
and future homes more energy efficient. These factors include central air vs. a.c. window
units, blower door test, and color of roof shingles, external air intake, insulation, and air
leakage. By using Energy 10 software, the team will try to find the most effective and
efficient home designs.
Project Tasks

The goals of this project are to develop baseline utility cost information for standard

homes offered by Habitat and to lower the cost of owning and operating a Habitat home

by finding ways to improve the home’s energy efficiency. Potential energy saving design

changes are studied, and the annual utility savings are compared to the initial cost of

implementing the change. If a design change is cost effective, it should be incorporated

into future home designs. By implementing design improvements on future Habitat

homes, future homeowners will benefit from lower home operating costs. According to

Habitat for Humanity’s website, low-income homeowners pay (by percentage) more for

utilities than middle class homeowners do. By decreasing the amount of money that

Habitat homeowners have to pay for utilities, the homeowners will have more money in

their pockets to provide for other family needs and expenses.      The other goal of this

project is to calculate baseline energy use and cost data for current home designs that are

developed by the Architecture team. The baseline energy data will be given to the Web

team to be put with the floor plans so the potential home owners will know

approximately what the energy use of each home will be when they are choosing a home.



In order to accomplish the team goal of calculating the energy usage profiles of all

current Habitat designs, each standard design must be entered into Energy 10, and its

energy usage must be calculated. Most Habitat for Humanity homes are similar in design.

Therefore, analysis of modifications to one home design should carry over to other

homes. Most Habitat houses have 2x4 exterior walls and one foot overhangs. Since most

families install window air conditioning units, this basic home has an air conditioning
system with an EER of 8.5 in order to simulate window a/c.            These major home

characteristics were entered into Energy 10.        Another influence on home energy

consumption is lighting. The electrical plan was used to approximate the lighting density

of the home. A lighting profile was developed in order to simulate a family turning the

lights on in the morning and turning them off at bedtime. Another important home

characteristic is its effective leakage area, ELA, which allows for air infiltration. This

was measured during a blower door test in November 1998. We plan to attempt another

blower door test later this semester. An ELA of 43.4 in2 was calculated in 1998. Also,

the houses were oriented with the front facing in all four directions (North, South, East

and West) in order to test each of the four possible layouts a home may have. It cannot be

foretold how Habitat will layout the home when it will be built. Weather data and utility

rates for the home's location are also needed to calculate the home’s energy usage and

cost. For this simulation, Indianapolis weather data is used because it is the closest city

to Lafayette within the available weather data at the Energy 10 website,

http://www.psic.org. The local residential electrical rates obtained from Cinergy/Psi

Energy are on a graduated scale. In addition to a monthly service charge of $8.15, the

first 300 kWh used per month cost .081711 $/kWh. The next 700 kWh cost .048510

$/kWh, and for over 1000 kWh it costs .040610 $/kWh. Since the average power usage

per month calculated by Energy 10 is about 600 kWh, an average cost of .065 $/kWh is

used to calculate utility costs. The Indiana Gas Company charges a monthly service fee

of $9.45, and the natural gas costs .51 $/therm for the first 45 therms and .44 $/therm for

any amount over 45 therms. For the simulation a cost of .51 $/therm is used since the

amount of gas used by the home is less than 45 therms.
The primary tool used to estimate the baseline utility costs and the energy savings

associated with design modifications is a software package called Energy 10. Energy 10

was produced through a partnership of the Passive Solar Industries Council, the National

Renewable Energy Laboratory, the Lawrence Berkeley National Laboratory, and the

Berkeley Solar Group. It was designed as a tool to evaluate energy usage and cost, and

to provide energy saving suggestions for commercial, institutional, and residential

buildings. Energy 10 takes numerous inputs from floor plans and designs, including total

volume of the house, construction materials, air infiltration models, lighting profiles,

local utility costs, shading, insulation, and so on. After all of the elements of the house

have been put into the program, Energy 10 simulates a year of energy use, using weather

data of a selected city. The simulation runs through an entire year, evaluating and

predicting house energy usage and cost on an hourly basis based on inputted house

designs, climatic data, and local utility costs. An example of the output from a home

analysis is shown in Appendix A. Energy 10 can also be used to calculate monthly energy

costs for people living in a home. These variables are quickly simulated, evaluated, and

displayed in a series of user-friendly charts and graphs.



Using Energy 10, a design tool for low-rise buildings, calculates the energy and utility

savings from each proposed change. First, the specifications of a current home will be

entered into Energy 10 to create a base home model. Then, the proposed modification

will be applied to the Energy 10 home model, and the annual savings from reduced utility
costs are calculated. Upon calculating the cost of the change, a final cost analysis is

reached. This semester we plan to analyze:



          Central air vs. fans and window air units

          Blower door test for air leakage

          Rolled insulation vs. blown insulation

          Color of roof shingles

          External air intake for the furnace

          Thermal imaging

          Programmable thermostat

          House wrap



The team of five members broke up into two sub-teams with a team leader. With sub-

teams, it is easier to communicate and find time to work together when dealing with less

people. Brent Phillips acts as the team leader and works with both of the sub-teams. Asli

Kumcu and Drew Susott make up one of the sub-teams while Jeff Bryles and Adam

Stanczak form the other. Brent Phillips acts as a representative of the energy team and

meets with representatives from the other two teams, Architecture team and Web team, to

correlate progress of the Habitat team as a whole. The beginning of our semester

involved learning the new Energy 10 software and analyzing different home designs.

Three floor plans were analyzed using Energy 10 and monthly utility costs were found.

For the rest of the semester, different analyses will be taken of home variables that may

be changed.
                                   Appendix A
Plan1278_4A1                                                 Sep 29, 1999
Energy 10 Summary Page                                               Weather file: Indy.et1
Variant: AutoBuild Shoebox                                   Saved as T:\1278_4A1, Var. 1
Comments:

Description:                  Reference Case              Low-Energy Case
Floor Area, ft²                      1278.0                     1278.0
Surface Area, ft²                             3892.0                     3892.0
Volume, ft³                          10224.0                             10224.0
Surface Area Ratio                   1.38                       1.38
Total Conduction UA, Btu/h-F         300.3                      229.0
Average U-value, Btu/hr-ft²-F        0.077                      0.059
Wall Construction                    2 x 4 frame, R=14.8        steelstud 6 poly,
R=19.2
Roof Construction                    attic, r-30, R=29.4        flat r-38, R=38.0
Floor type, insulation               Crawl Space, Reff=23.7              Slab on Grade,
Reff=38.3
Window Construction                  4060 double, wood, U=0.47 4060 low-e al/b,
U=0.31
Window Shading           None                                            40 deg latitude
Wall total gross area, ft²                    1336                       1336
Roof total gross area, ft²                    1278                       1278
Ground total gross area, ft²                  1278                       1278
Window total gross area, ft²         240                        336
Windows (N/E/S/W:Roof)                        5/2/1/2:0                  3/1/8/1:1
Glazing name                         double, U=0.49             double low-e, U=0.26


Operating parameters for zone 1
HVAC system                           Heat with Gas Furn            Heat with Gas Furn
Rated Output (Heat/SCool/TCool),kBtuh         48/0/0                        65/0/0
Rated Air Flow/MOOA,cfm               593/0                         988/0
Heating thermostat                    72.0 °F, no setback           72.0 °F, setback to
67.0 °F
Cooling thermostat                    72.0 °F, no setup                     72.0 °F, setup
to 77.0 °F
Heat/cool performance                 eff=80,EER=1.0
         eff=90,EER=13.0
Economizer?/type                      no/NA                         yes/fixed dry bulb,
60.0 °F
Duct leaks/conduction losses, total % 11/10                         3/0
Peak Gains; IL,EL,HW,OT; W/ft²                0.20/0.04/0.66/0.36
         0.15/0.03/0.66/0.36
Added mass?                           none                          639 ft², 8in cmu
Daylighting?                          no                            yes, continuous
dimming
Infiltration, in²                     ELA=177.7                     ELA=48.1