Montana Superinsulation Project Background
In the late 1970s, researchers concluded that the best deal
for consumers was to build with high levels of energy conservation
at time of construction, rather than looking for a more efficient
heating or cooling system while the house stayed inefficient.
Several research and demonstration houses in Canada and the Northwest
led to the development in 1982-4 by Corbett/Hansen and Associates
of detailed house plans that transferred the technology known
as "superinsulation" in new residential construction
for cold climates.
The Montana Superinsulation Project was designed to document
the performance of this highly affordable cold-climate prototype.
Funded by the state of Montana, a group of research organizations
banded together to develop a highly useful study of the potential
of these particular energy measures.
The project was based on more than six years of research,
including optimization studies and computer simulations of performance.
These studies led to these unique stock house plans that showed
the methods in great detail.1/
The goal of the house plans was to make it easy for builders,
no matter what the experience level, to correctly use the new
methods. Changes in construction approach were aimed at making
energy-saving techniques easy to employ, and through overall
engineering of the house, costs were kept at or below overall
costs for a house of this type.
The Montana project featured the construction of five thermally
identical houses from a detailed stock house plan, a 1,288 square
foot ranch-style home with a full basement, for 2,400 square
feet of living space.
A variety of research projects were undertaken at the five
houses, and they were the focus of the project's public information
and builder education campaigns.
The House Plans and the Builders
Builders in the Montana project included an inexperienced
owner-builder couple, a young contractor who used the house as
his first professional project, and three professional contractors
with various degrees of familiarity with these methods. Three
of the builders took part in a two-day training program, while
two others did not. One goal of the project was to test the use
of detailed house plans as a means to ensure energy performance.
Measurements and Tests
To verify the expected thermal performance of the sites and
better understand the occupants' influence on energy consumption,
each site was instrumented with a 17-channel data acquisition
system that collected hourly thermal measurements, including
indoor temperature, outdoor temperatures, solar radiation, temperatures
in the ventilation system, and electrical consumption for space
heat, hot water, clothes dryer, and overall consumption. Gallons
of hot water used were also a part of the project. Continuous
hourly data were collected for more than two years. In addition,
fan pressurization tests, using a blower door, were conducted
three times during the project.2/
Heat Recovery Ventilation Field Study
In 1986, the Montana Superinsulation Project received support
from the Northwest Power Planning Council, the Bonneville Power
Administration, and Montana to perform an in-depth study of the
heat-recovery ventilation (HRV) systems in two of the sites.
One goal of the study was to characterize the energy and ventilation
delivery performance of these systems, which represented a state--of-the
art (1984) installation. The project house plans were the first
in the nation to show the HRV integrated into the architecture
of the house. An additional 36 channels were added to the measurement
system, with hourly data collected from the two sites through
mid-1987. This testing focused primarily on the ventilation system.
In addition, the project conducted a pioneering study of the
use of perfluorocarbon tracer (PFT) to measure ventilation effectiveness.
Thermal Results
Space Heat Savings - The houses used an average of 66 percent
less space heating than control houses built to current practice
(HUD Minimum property standards) by BPA in Montana. Total annual
average electrical savings were projected at 10,900 kilowatt
hours (kWh). At national average electricity prices, these savings
would have a value of about $817 annually. Total space heating
costs annually were only $311 in climates with more than 8,000
heating degree days. The houses also compared favorably with
those built to the regional Model Conservation Standards proposed
by the Northwest Power Planning Council, saving more than 2,000
kWh ($150 at national electricity prices) over these energy-efficient
homes built in Montana. Moreover, the houses performed very similarly
in regard to measured thermal performance. The project illustrated
the impact of occupant preference on performance. Space heat
consumption varied from two to one across the houses, based on
differences in thermostat settings and preferences for temperature
differences between rooms.
Hot Water Savings - On average, the houses used about 36 percent
less electricity for hot water than did the control houses built
by BPA. A total savings of about 1,900 kWh (about $140 at national
electricity prices) annually on average were reported across
the sites.
Ventilation results - The study showed that the HRV provided
an average of about 22 percent of the total space heating savings
achieved at these houses, while providing a continuous and controllable
level of ventilation throughout the heating season. While the
houses generally stayed comfortably cool in summer, the HRV's
were also used as part of a cooling strategy in summer during
particularly hot weather.3/
Consumption Summary - The houses used less than 5,000 average
kWh per year for space heat, compared to more than 15,000 kWh
per year for houses built to current HUD standard. Total annual
savings combining hot water and space heating was $950. Occupants
rated the homes as very comfortable and were able to set thermostats
at a comfortable range at an affordable cost.
Conservation Costs
As built from the Montana project house plans, the houses
were sold for a complete cost of $25-35 per square foot, depending
on land and finish costs. According to the project builders,
these houses with conservation features properly engineered into
the house, cost no more to build than conventionally constructed
homes without these conservation features. This means that the
payback for adding the conservation features in this case was
immediate.
Without this attention to reducing other costs throughout
the construction process, the marginal cost for the conservation
measures in similarly sized houses has been reported to be about
$3,000, depending on builder expertise and other factors.4/
If the Montana Superinsulation Project houses had these marginal
costs, the payback on the measures would still be under four
years.
In the Montana project, the extra cost for the hot water conservation
improvements was less than $50. The hot water system is a conventionally
priced electric tank hot water heater that is more efficient
and better insulated, in which standby losses from the tank are
cut to a minimum through easy-to-install conservation improvements.
The payback on these measures is about four months.
Clearly, these conservation improvements, as demonstrated
in the Montana project, were very cost effective. The project
also proves that these improvements are possible in housing that
is very low cost, by any standard.
Public and Practitioner Outreach
Due to the fact that the house plans were well-researched,
and that the results were fairly certain, the Montana project
team confidently included builder training and public information
activities as a major part of the Montana project. Public open
houses were conducted in the winter of 1985, with more than 1,000
Montanans touring the homes. The computer data logger system
was developed with the idea of these open houses, and was a real
focal point for explaining the performance of the houses. (In
sub-zero weather, people could see for themselves that no space
heat was required.)
In addition, builder training programs were conducted for
about 100 builders in Eastern Montana. A special manual was developed
for this outreach, and the State of Montana distributed 1,000
copies of this five-publication manual to builders throughout
the state as a part of the program.
Another part of the project was an international and regional
conference on energy conservation in buildings, held in Butte
in May 1985. Conservation in Buildings: Northwest Perspective
was a conference dedicated to putting the Northwest conservation
programs and results into a context with those in Canada and
elsewhere. Another aim of the conference was to assist the Northwest
in building relationships among the professionals in research,
building construction and program administration. The conference
featured the pre-publication of a 450-page proceedings containing
more than 50 papers from the region and Canada.
In the last several years, Montana project staff have worked
to transfer lessons learned in this project and the Pacific Northwest
in general through the development of a technical network of
research and assistance organizations called the National Affordable
Housing Network. The goal of the Network is to rally resources
to bridge the gap between the energy community and low-cost housing
producers, including design, research, technical assistance and
training.
Research, Verification and Technology Transfer are Critically
needed in Low-Cost Housing
Combined with data from other field projects, the Montana
results illustrate the vast "lost opportunity" of energy
and water savings in low-cost housing. Based on available knowledge
and technology, excess energy and water charges of $350 to $1,000
a year per household are currently being borne by those who can
least afford it. The federal budget for low-income energy costs
is more than $2.3 billion a year, but only a quarter of those
in need are being served, with an estimated 20 million household
going without help with energy bills, resulting in the loss of
heat for part of each winter for many low-income households.
Since more than 5,000 organizations provide low-cost or affordable
housing across the country, there are many challenges to address.
The Network's goal is to provide technical guidance to five climate
regions to develop thermal recommendations for efficiency in
low-cost housing, including new construction, rehabilitation
and manufactured housing. The Montana Superinsulation Project
suggests certain principles of technology transfer that may help
ease the transition toward greater resource efficiency:
The technology or method change must be built on firm research.
Technology transfer of methods that are not well understood
or researched can lead to poor results or even disaster. Over
the years, Network staff routinely receive reports from the field
related to difficulties or building failures due to misapplication
of new methods or technologies. These failures lead to unfair
judgments as to the effectiveness of a properly applied technology
as well as slow down overall transfer of good approaches.
The results of research and analysis may best be transferred
through graphic forms, such as detailed house plans.
The house plans used allow an inexperienced builder to learn
about energy-conserving methods and the technical application
of them, as well as learn good standard practice in non- energy-related
construction techniques. This makes this type of plan highly
useful to owner-builders, students, and those entering the construction
trades. The plans represent a synthesis of cost, energy and construction
practice that allows energy efficiency at an overall cost that
is the same or even less than that of a conventionally built
house.
Direct information and education of occupants and builders
is highly desirable to effect orderly technology innovation.
All successful technology transfer programs feature a combination
of direct technical assistance, information and education to
all groups affected by the changes. Along with well-documented
specifications for change in rehabilitation and manufactured
housing, technical assistance is critical to the success of the
change.
For more information on this project or to request information
about the Network's other work, contact the National Affordable
Housing Network, Barbara Miller, Executive Director, P.O. Box
3706, Butte, MT 59702; (406) 782-8145; (406) 782-5168; or send
e-mail to nahn@nahn.com
References
1/ "A Low-Cost, Three Bedroom, Two-Bath Superinsulated
House for Cold Climates: (House Plans), Version 2.1, copyright
1984, Superinsulation Designs/Corbett-Hansen and Associates.
This version of the house plan was used for three of the Montana
houses. Version 2 was used for the other two. Other plans in
the series include a small, two-bedroom house (Plan1), and a
modular version of the same house (Plan 1M). Call or write the
Network for information about these plans.
2/ Superinsulation Close-Up: Results from the Montana
Superinsulation Project Thermal; Measurement Effort, pre-publication
draft, October 1986, This report includes most of the technical
papers produced during the course of the project, as well as
the project references. For information about this report, call
or write the Network.
3/ Heat Recovery Ventilation for Cold Climates: Field
Experience in Montana, Aug. 31, 1987. This final report describes
the history of the HRV technology and summarizes results from
the Montana experience. For information about this, write or
call the Network.
4/ A Review of Costs and Benefits, Five years of Experience
under the Northwest Power Act, draft report of the Northwest
Power Planning Council, Portland, Oregon, July 14, 1987. This
draft report includes estimates of unit costs for conservation
improvements in new construction programs supported by BPA in
the Pacific Northwest, as well as an evaluation of the last five
years' effort in conservation research and implementation in
the Northwest.
