August 16, 1996
Nebraska Energy Office
Introduction
The Low Income Weatherization Assistance Program is a
federally funded program for weatherizing homes to save
money and energy. It is administered by the Nebraska
Energy Office. The objective of the program is to
increase the energy efficiency of dwellings occupied
by low-income persons in order to reduce their energy
consumption, thus lowering their energy bills while
simultaneously increasing the comfort of their homes.
The program targets vulnerable groups including the
elderly, people with disabilities and families with
children.
This report presents the results of an evaluation of
the energy savings and cost effectiveness of the program
based on a sample of homes weatherized during May-September
1994.
May, 1995: Decision was reached to
perform an analysis of the Low Income Weatherization
Assistance Program. Further, it was decided to select
homes for the study from those weatherized in the
period May 1, 1994 - September 30, 1994. Also, only
the impact on heating fuel use was to be evaluated.
Homes were selected from this time period so that only
one request for energy consumption data covering the
12 month period prior to weatherization and the 12 month
period immediately after weatherization would be made
to fuel suppliers, and so all requests for data could
be completed by late summer 1995. A random sample of
247 weatherized homes and 3 multi-family units was
selected from the target group.
June, 1995: As part of the request
for weatherization assistance, each participant signed
a fuel information release form permitting access to
past, present and future fuel billing information.
Copies of these releases for the sampled homes were
requested from the nine Weatherization Subgrantees
during the second week of June and all requested releases
were received by June 27, 1995.
July, 1995: A list of fuel suppliers from whom data would be requested was begun. A
list of sampled homes was prepared for each identified fuel supplier. Preparation of the list of
fuel suppliers was more difficult than anticipated for the following reasons:
- For most participants, only the name of the fuel supplier was included on the
signed release. This resulted in considerable time and effort being expended to
obtaining accurate addresses for the fuel suppliers.
- One agency only identified the type of fuel used on the release form, with no
information about the fuel supplier. A further request was required to identify
the fuel suppliers, with the resulting list containing several errors.
- Only one agency included the customer account number on the signed release.
Although no attempt was made to obtain these numbers, their presence would
have made it easier for some utilities to supply the requested data.
August, 1995: The list of fuel suppliers with complete addresses was completed. A
request was made to the subgrantees for a letter authorizing the Nebraska Energy Office to
collect data for the analysis on behalf of the agencies. The last letter was received on September
15, 1995.
September, 1995: Letters were mailed to 57 fuel suppliers requesting data on fuel
consumption of 224 sampled homes and 1 multi-family housing unit during the last week of
September. Data was not requested on the remaining homes sampled, primarily because the
current resident had not lived there for 12 months prior to participation in the weatherization
program.
October, 1995: Data was received and reviewed for 95 homes and the multi-family
housing unit. Phone conversations with the fuel suppliers for nearly 100 additional homes
revealed that only 14-16 months of data were maintained on their computer systems and that it
would be extremely time consuming for them to retrieve it from their archives. Since adequate
useable data had been received, it was decided not to pursue this data. Replies from suppliers
concerning an additional 12 homes indicated that they did not sell fuel to the specified
customer(s).
November, 1995 - March, 1995: Energy data and weather data were entered in PRISM
Advanced Version 1.0. PRISM is a computer program developed by Princeton University to
estimate annual energy consumption, normalized for weather.
March, 1996: Weather data from the publication Climatological Data, Nebraska
published by the National Oceanic and Atmospheric Administration, Asheville, North Carolina
was required for the analysis. The last such weather data was received in late March.
April, 1996 - June, 1996: Data analysis and evaluation performed.
Homes weatherized by the Low Income Weatherization Assistance Program have reduced
energy consumption, reduced energy bills and reduced emissions of greenhouse gases.
The average home weatherized during program years 1993/94 and 1994/95 saved an
average of 18.7% of total consumption of the fuel used for heating. This resulted in an average
reduction of $126 in annual utility bills. Due to the decrease in energy use, these homes also
contributed to reducing emissions of greenhouse gases. On average, each home reduced carbon
dioxide emissions by 2,297 pounds, sulfur dioxide emissions by 0.435 pound, and nitrogen
oxides by 0.706 pound.
Sample and program results are presented in the following sections of this report.
Data for 62 homes was found suitable for input into PRISM for further analysis. For
most of those found not suitable, data was only provided for 14 months because that was all the
fuel supplier had readily available on the computer. An additional two homes were dropped
from analysis when the estimates of annual consumption from PRISM were rated as statistically
unreliable.
The 60 homes in the final analysis were grouped as follows:
- Mobile homes (13),
- Single family frame - heated by fossil fuels (37), and
- Single family frame - heated by electricity (10).
In addition, the data from the one multi-family housing unit was analyzed.
Energy savings for the sample are summarized in the following table:
Group |
Sample Size |
Heating Fuel |
Pre-Wx Use
(mmBtu) |
Post-Wx Use
(mmBtu) |
Savings
(mmBtu) |
% Savings |
Mobile |
13 |
natural gas (10)
propane (2)
electricity (1) |
121.6 |
108.1 |
13.5 |
11.1 |
Frame - fossil fuel |
37 |
natural gas (26)
propane (10)
heating oil (1) |
109.9 |
84.9 |
25.0 |
22.7 |
Frame - electricity |
10 |
electricity (10)
---site*
---source* |
79.3
242.9 |
71.0
217.3 |
8.3
25.6 |
10.5
10.5 |
Multi-family** |
1 |
natural gas |
2,172.4 |
2,026.1 |
146.3 |
6.7 |
* site refers to Btu content at point of end-use (3,413 Btu/kWh)
* source refers to Btu content of fuel used to generate electricity (10,450 Btu/kWh)
** 1 multi-family housing facility with 17 weatherized units
|
Single family frame homes heated by fossil fuels realized the greatest energy savings of
22.7% of total fuel use, next was mobile homes at 11.1%, single family frame homes heated
by electricity 10.5%, and multi-family housing units 6.7%.
Costs and dollar savings for the sample are summarized in the following table:
Group |
Costs, Total |
Costs, Labor and Materials |
Costs, Materials |
Average Dollars Saved |
Simple Payback
(in years) |
Discounted Payback
(in years) |
Mobile |
1,764 |
1,374 |
883 |
90 |
9 |
27 |
Frame - fossil fuel |
2,105 |
1,715 |
954 |
141 |
14 |
20 |
Frame - electricity |
1,108 |
718 |
399 |
142 |
7 |
10 |
Multi-family |
10,318 |
3,688 |
1,963 |
778 |
13 |
18 |
The dollars saved considers only the savings due to reduced
heating fuel consumption, and would be expected to be higher
for all but the electrically heated homes due to additional
savings on air conditioning bills during the summer months.
Also, no attempt has been made to include the dollar benefits
associated with the employment impact of the weatherization
program, the economic benefit of reduced greenhouse gas
emissions, the value of increased comfort in weatherized
homes, as well as other benefits due to the program. Total
costs include only those directly attributed to the weatherization
work and do not include administrative costs of the Nebraska
Energy Office nor the Weatherization Subgrantees.
It is assumed that work performed under the weatherization
program has a useful life of 20 years. Thus, energy savings
alone pays for the weatherization work in all groups when using
simple payback, and for all but mobile homes when considering
the discounted value of costs and benefits.
During the 1993/94 and 1994/95 program years covered by the above sample of
weatherized homes, a total of 3,721 units were weatherized. These homes were categorized into
the groups above based on information maintained by the Weatherization Division of the
Nebraska Energy Office, the original sample selected, and census information about the source
of heat for Nebraska homes. In summary, it is assumed that the weatherized units were:
- Mobile homes: 595
- Single family (heated by fossil fuels): 2,605
- Single family (heated by electricity): 223
- Multi-family: 298 units (or 17.53 buildings)
A summary of the energy savings by fuel type is presented
in the following table for all homes weatherized during
program years 1993/94 and 1994/95. These savings are presented
in both physical units and million Btu. The million Btu savings
are also provided for the 20 year life of the projects.
Fuel Type |
Physical Units |
1st Year Savings |
20 Year Savings |
1st Year million Btu Savings |
20 Year million Btu Savings |
Natural Gas |
therms |
541,357 |
10,827,142 |
54,136 |
1,082,714 |
Heating Oil |
gallons |
41,694 |
833,901 |
5,783 |
115,662 |
Propane (LPG) |
gallons |
153,623 |
3,072,461 |
14,671 |
293,420 |
Electricity |
kWh
..Btu-site
..Btu-source |
850,864
--
-- |
17,017,580
--
-- |
--
2,904
8,892 |
--
58,081
177,834 |
Total Btu Savings |
site
source |
--
-- |
--
-- |
77,494
83,482 |
1,549,877
1,669,630 |
Total first year program savings of 77,494 million Btu
represent an 18.7% reduction in site energy use, or the
first year program savings of 83,482 million Btu represent
an 18.0% reduction in source energy use.
Total first year energy bill dollar savings was $468,064
compared to a total weatherization cost of $6,961,053. This
represents a simple payback in the 14th year for energy
savings alone. In discounted dollars, payback occurs in
the 20th year.
Although a discounted payback in the 20th year does not
look very impressive, one should keep in mind that the
following benefits have not been included in the economic
analysis:
- energy saved in air conditioning expenses, except
for homes heated by electricity
- the dollar value of the reduction in emissions
of greenhouse gases
- employment and related tax values created by the program
- improved comfort level of homes weatherized
- improved safety level of homes weatherized
In addition to reducing energy consumption and thus the energy
bills, homes that are weatherized are also benefitting society
because of the reduction in greenhouse emissions resulting from
their reduced energy use. First year reductions by fuel type and
greenhouse gas are summarized in the following table:
Fuel Source |
Carbon Dioxide
(short tons) |
Sulfur Dioxide
(pounds) |
Nitrogen Oxides
(pounds) |
Electricity * |
466.5 |
1,325.5 |
813.9 |
Heating Oil |
381.5 |
286.5 |
166.4 |
Natural Gas |
2,600.0 |
5.2 |
1,013.6 |
Propane |
836.5 |
2.1 |
633.9 |
Total |
4,284.5 |
1,619.3 |
2,627.8 |
* - emissions for electricity weighted by fuels used to
generate electricity in Nebraska
|
The following list of recommendations, are primarily
predicated on the fact that there will be another evaluation
of the program sometime in the future.
- Don't try to obtain all energy data with one request.
Make a first request for pre-weatherization energy data
shortly after the work is completed. Follow-up with a
request for post-weatherization energy data 12 months
after completion of the work. This will make it easier
for the fuel suppliers to provide the necessary data.
- Include savings due to air-conditioning. Although minor
in comparison to the savings due to heating, inclusion of
this information would result in a more accurate picture of
the cost effectiveness of the program. To include this factor
in the evaluation would require that when getting the signed
release for the heating fuel, a release would also be obtained
for electric data.
- All of the Weatherization Subgrantees should review their current fuel supplier release
form to ensure that the release contains all needed information. This information should include:
the heating fuel used, the name of the supplier, the address of the supplier, and the account
number. This information could be assured by attaching a copy of a recent bill.
- As part of any future evaluation, all weatherization expenses should be accounted for,
including Energy Office and subgrantee administration expenses.
- If possible, as part of any future evaluation, a control group should be used for
comparison and as added validation of the results for homes participating in the weatherization
program.
National Impacts of the Weatherization Assistance Program
in Single-Family and Small Multifamily Dwellings, by Marilyn
A. Brown, Linda G. Berry, Richard A. Balzer, and Ellen Faby.
Oak Ridge National Laboratory, Oak Ridge, Tennessee (1993).
PRISM (Advanced Version 1.0), Computer program developed
by Center for Energy and Environmental Studies, Princeton
University, Princeton, New Jersey (1995).
BLCC4 4.3-96 and EMISS 1.0, Computer programs
developed by U.S. Department of Commerce, National Institute
of Standards and Technology, Washington, D.C. (1995).