Low Income Weatherization
Energy Savings Analysis
Nebraska Energy Office
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
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
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
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
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
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
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
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:
||natural gas (10)
|Frame - fossil fuel
||natural gas (26)
heating oil (1)
|Frame - electricity
* 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:
||Costs, Labor and Materials
||Average Dollars Saved
|Frame - fossil fuel
|Frame - electricity
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
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.
||1st Year Savings
||20 Year Savings
million Btu Savings
million Btu Savings
|Total Btu Savings
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:
emissions for electricity weighted by fuels used to generate electricity
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. Followup 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, DC (1995).