The 10 most cost-effective energy upgrades
A new study helps remodelers and home performance
contractors prioritize needed home improvements.
By Jeffrey Lee
Here's one thing that remodelers and contractors
interested in home performance work don't need to search very hard for: new
business. Spurred by state and federal government incentives, utility
initiatives, and high energy bills, homeowners across the country are seeking
ways to improve their homes to save energy. From 2006 to 2011, national
annual electricity efficiency program spending tripled from $1.6 billion to
about $4.8 billion, and natural gas efficiency programs increased from
$0.3 billion in 2006 to $1.1 billion in 2011, according to a
recent report from the American Council for an Energy-Efficient
But while the source of new business may be
straightforward, the path to achieve it isn't always quite so clear. For many
homeowners, conducting a whole-house energy retrofit is prohibitively
expensive. For these owners, and for the remodelers and home performance
contractors who advise them, that leads to a reasonable question that can be
difficult to answer: "What are the most cost-effective changes I can make to
improve the energy efficiency of my home?"
A new study by Newport
Partners LLC, a Maryland-based training and research firm focused on the
building industry, helps answer that question by providing information on
prioritizing energy upgrades. The "Whole-House Analysis of Energy Efficiency Upgrades for Existing Homes" evaluates dozens of energy
efficiency measures (EEMs) for their energy, economic, and environmental
performance at 10 locations across five climates zones. The study provides a
credible performance analysis to help prioritize competing EEMs, with added
focus on the performance of propane systems.
simulation models require dozens of inputs to be able to characterize the
interrelationships of building systems, so the study used a "typical"
reference home based on historic housing data that defines standard
characteristics of existing homes. The study then evaluated dozens of
household upgrades, or EEMs, and categorized them as elective (building
envelope upgrades or renewable energy systems, for instance) or non-elective
(systems that would require immediate repair or replacement, such as
mechanical systems or lighting).
performer across all climates was a high-efficiency propane furnace in lieu of
a standard propane furnace."
Each measure was evaluated in
terms of its payback — how much time it takes to recoup the net first costs
of a system, based on annual energy cost savings — and by the annual
CO2 emissions savings. The study also identified the
savings-to-investment ratios (SIR), a metric used by weatherization programs
to evaluate the economic value of an energy efficiency measure. The higher
the SIR, the more attractive the measure is from an economic standpoint.
The study's final report provides extensive detail on the findings by
climate zone for each EEM evaluated. But the study identified 10 systems
that are worthy of consideration throughout most of the country.
Click the image above for a
- Air sealing consistently had the best payback
across all five regions, at one to four years. This measure assumes that
a 30 percent reduction in air infiltration could be realized through
typical air-sealing efforts.
- Attic insulation
had the second best payback across all regions, ranging from three to five
- Aerosolized duct sealing paybacks ranged
from four to seven years in all climates except the Northeast, where
boilers were the most typical means of winter heating, reducing the
impact of ductwork on space conditioning.
windows were found to offer paybacks of 10 years or less in all
climates except the Northeast, where survey data has shown existing
windows to have considerably better thermal properties than in other
- Propane fireplace inserts were
economically attractive in the two colder climates, with a payback of six
to seven years.
- Lighting. Replacing existing incandescent
lighting with high-efficacy fluorescents was a consistently strong performer
with paybacks of one year or less in all climates and annual emissions
savings of 0.2–1.2 tons of CO2.
dryer. Selecting a propane clothes dryer over an electric
clothes dryer showed the most attractive payback in the three colder
climates, with paybacks between four and six years.
- Space heating. The economic and efficiency
performance of space heating EEMs were highly dependent on climate, but
a consistent performer across all climates was a high-efficiency propane
furnace in lieu of a standard propane furnace. The high-efficiency
furnace offers a one-year payback in mixed-humid, cold/very cold, and
Northeast regions. The associated annual emissions savings are 1.9–3.4
metric tons of CO2 — higher emissions savings than any
lighting or appliance EEM analyzed across all climate zones.
- Dual-fuel systems, composed of a high-efficiency air
source heat pump working in tandem with a high-efficiency propane
furnace, also performed well. When replacing a furnace in all climates,
they had simple paybacks of four to six years and showed high emissions
savings, with over three metric tons of CO2 emissions
savings in all climates when chosen over a standard forced-air furnace.
- Water heating. In the Northeast, specifying a
propane tankless unit over an electric tank has a payback of five years
and annual emissions savings of 0.6 metric tons of CO2, while
also offering longer life expectancy and delivering hot water at nearly
triple the hourly rate.
Dig into the results yourself so
that you can help homeowners make informed decisions on energy