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Including Wood Stove in Energy Audits
John AckerlyPresident, Alliance for Green Heat
The challenges of assessing an age-old technology with modern standards
Alliance for Green Heat
501c3 nonprofit funded by foundations & grants A national voice for wood heat consumersWork for more incentives for the cleanest & most
efficient biomass heaters Call on government to provide R&D funding for
ultra-clean “next generation” stovesWork for more regulation of wood stoves, including
No new installs of unqualified outdoor boilersNo new installs of uncertified stoves in urban
areas
There are no standards to assess the second most common heating appliance in New England
Building Performance Institute, Inc. BPI-101 Home Energy Auditing Standard
August 3, 2010 3.3 Include a test of all combustion appliances in accordance with Section 7 of this standard.
What are the challenges?Most wood and pellet stoves do not report reliable efficiency numbers
Wood and pellet stoves emit carbon monoxide, yet they are never tested for leaks and cannot be run if a blower door test is being done
Pellet stoves and boilers are exempt from EPA regulation, so they cannot be checked for EPA certification
2.4 million US homes use stoves as their primary heat but many homeowners, insurance companies and even some states do not consider stoves primary heating devices.
There is no EnergyStar program for wood or pellet stoves
?
Wood stoves in BPI standardsThe Home Energy Auditing Standard (BPI-1100-T-2012):
7.8: Energy auditors shall Inspect solid fuel burning appliances for safe operation and efficiency.
7.23: Energy auditors shall recommend replacement of solid fuel burning appliances with UL-listed and EPA-certified appliances if the existing appliance is not UL-listed or has signs of structural failure.
BPI Standard Process
Solid Fuel Working Group Alliance for Green Heat – Chair EPA National Fireplace Institute Chimney Safety Institute of
America Washington State Dept. Ecology Hearth, Patio BBQ Association
Advising Homeowners on New Equipment
Helping homeowners do a cost-benefit calculation for wood or pellet stoves or boilers (all numbers in HHV). The pellet efficiencies tend to be unrealistically high, as is Maine’s 85% estimate for biomass central heating systems.
Department of Energy Home Fuel Cost Calculator:www.eia.gov/neic/experts/heatcalc.xls Default wood stove efficiency: 72% Default pellet stove efficiency: 78%
State of Maine Home Heating Calculatorwww.maine.gov/energy/fuel_prices/heating-calculator.php Default wood stove efficiency: 63%, EPA certified; 54%, noncertified Default pellet stove efficiency: 80%, stove; 85%, central heating system
BuildingGreen.com Heating Fuel Cost Calculatorwww.buildinggreen.com/calc/fuel_cost.cfm Default wood stove efficiencies: 80%, masonry; 70%, high efficiency EPA; 60%, wood stove;
50%, older wood stove Default pellet stove efficiency: 80%
What Consumers Need to Know: Pellet Stoves
Myth #1: Advertised efficiency numbers can be relied on.Advertised efficiency numbers are calculated in many different ways
and are not reliable. They are almost always in LHV, even though EPA uses HHV. Make sure stove is over 70% HHV or 80% LHV using the B415 method.
Myth #2: Pellet stoves tend to be more efficient than wood stoves.
Many pellet stoves are fuel-guzzlers with low efficiency numbers. Expected savings may never materialize.
Myth #3: Pellet stove are automaticYes, but professional annual cleaning, and monthly homeowner
cleaning, are vital to best operation and to maximize efficiency.
Efficiency of wood appliancesAs tested at High Heating Value (HHV)
Pellet Catalytic Non-catalytic0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
Best KnownDefault (EPA)AverageWorst Known
Out of the top 24 pellet stove companies that retail in the U.S.The following is based on a review of manufacturer websites. 7 listed stove efficiencies7 make general efficiency claims, i.e. “our
stoves achieve up to 77% efficiency”10 do not mention any efficiency numbers8 provide emissions numbers in grams per
hour16 do not list their emissions
What consumers need to know: Wood StovesEfficiency: If efficiency is a real priority and the stove will be a
primary heater, consider a catalytic stove. Catalytic stoves got a deserved bad rap in 80s and 90s but designs are far better today. Woodstock Soapstone, Blaze King and Travis make great catalytic stoves and report B415 efficiency numbers. They all make stoves that are over 80% HHV efficiency (90% LHV). Non-cats are 10 – 20% less efficient.
Emissions: Key to low emissions is using dry, split wood, not the grams per hour as tested in the lab.
Sizing is key: Make sure stove is sized to the space it can effectively heat.
Professional installation: Find a pro certified by the National Fireplace Institute (NFI), http://nficertified.org.
What consumers need to know: BoilersMyth #1: EPA Qualified outdoor wood boilers are high efficiency.
Some are as low as 40- 50% efficient.Myth #2: EPA Qualified outdoor wood boilers are clean burning.
Huge door opening leads to many people to use unsplit, large logs which are far from seasoned, and create plenty of smoke.
Myth #3: Manufacturer and retailers help right-size boilersUnfortunately, many manufacturers and retailers have not done
enough to help consumers get the right size equipment, leading to many installations that are oversized.
How to inspect a wood stove
1. Physical inspection of stoveEPA certificationUL listingStructural integrity & rustGlass & gaskets
2. Inspection of clearances. 3. Inspection of evidence of smoke leakage4. Inspection of fuel and fuel storage.5. Inspection of visible creosote on chimney
We are not recommending at this point an inspection while stove is in operation.
Why is this important?
Power in Numbers20% of New England homes use wood heat (1.1 million homes)Half of New England rural homes use wood heat12% of urban New England homes use wood heat
Potential for DangerWood stoves cause 4,000 house fires each yearOver one-quarter of residential building heating fires resultfrom improper maintenance of heating equipment, specifically the failure to clean the equipment.
Wood is 3rd most common heat in U.S.
Electricity Natural Gas Wood Propane/LPG
Fuel Oil Kerosene0
10
20
30
40
50
60
70
US Residential Heating Fuel Use
SecondaryPrimary
Mill
ions
of U
S H
omes
EPA and UL certificationMake sure to checkBack of stove for EPA and
UL label.If brand and model are on
EPA certified list.Year purchased. Before
1988, not certified. After 1988, probably certified.
For glass door. If it has one, it’s likely certified.
Note: Pellet stoves do not require EPA certification.
Signs of structural failure
Cracks and rust in the body Cracks in the door and glass
GlassDirty glass is a sign the
stove owner is not operating stove correctly or the stove is inefficient.
Recommend the homeowner clean the glass every day to see how quickly it gets dirty. If it gets dirty in a single day, the combustion is poor.
Cracked glass should be replaced.
Clearances from combustiblesThese are very general guidelines and do not reflect legal requirements.
Inspect area for combustibles within 12 inches of stove (includes dry wall)
Old, uncertified stoves usually require 18 – 24 inches from combustible.
EPA certified stove usually require no less than 12 inches.
Minimum clearances are printed in the stove manual. If manual cannot be found, follow NFPA guidelines.
NFPA Recommended Clearances
Radiant Stove
Stove Pipe
Ceiling 36” 18”
Front 36” 18”
Side 36” 18”
Rear 36” 18”
Floor 18” 18”
Inspecting gasketsMissing or degraded gaskets
could lead to smoke and CO entering the house.
If the gasket around the stove door is loose, missing or degraded, recommend owner gets a replacement.
Gasket rope comes in different sizes, so tell the homeowner to consult owner’s manual before buying.
Smoke leakageCheck the interior of
the home for signs of smoke leakage, especially the fireplace and mantle in the case of wood stove inserts.
A leaky stove is a health and safety hazard and should be replaced.
ChimneysChimneys collect
creosote (tar), the leading cause of chimney fires, and should be inspected once a year.
Check for creosote by looking up the chimney with a strong flashlight. Creosote can be visible on the grate of the chimney cap as well.
BPI, Technical Standards for the Heating Professional says: “A deteriorated chimney must be repaired or relined and the cause corrected before reusing.”
Smoke & carbon dioxide monitors
Check if home has an operational smoke detector and carbon monoxide monitor and test them.
Smoke alarms should be on a ceiling or high on a wall. Carbon monoxide alarms should also be placed at least 5 feet high, but not directly above or beside wood stoves, since they may emit a small amount of CO upon start-up.
FirewoodInspect fuel storage to see if
wood is split, stacked and covered. Splitting and stacking is essential; covering is best.
Inspect wood to check if it is seasoned. Ideal is to test with moisture meter and show homeowner. Make sure you split wood and know how to use your meter.
Seasoned wood is 20% or less moisture. Unseasoned wood leads to inefficient, smoky fires.
Installation & repair certification
National Fireplace Institute (NFI) Non-profit certification
agency that trains, tests and certifies hearth professionals, mostly focusing on installation of new units.
Chimney Safety Institute of America (CSIA)Focuses on chimneys but
includes some hearth installation training.
When to designate a wood stove as a “Health and Safety hazard”?
Made before 1988 and not certified by the EPA?
No UL listing?Cracked firebox?Insufficient clearances?All of the above?
Low income homes using an old stove as a primary or heating unit may be eligible for assistance to get a new, clean, high efficiency stove
The Wood Stove ChecklistWritten by Alliance for
Green with support from the University of Maryland Extension as a tool for home energy auditors and others to help assess wood stove safety and efficiency
Available through the Extension website: http://www.naturalresources.umd.edu/Publications/FactSheets/FS-936_2012_Wood_Stove_Checklist.pdf
Send any feedback to [email protected]
Thank you!John Ackerly
301-841-7755
