How to inspect a wood stove: A visual guide for safety & performance

Updated October 2024

The Alliance for Green Heat developed a visual guide for inspecting wood stoves for the energy audit and weatherization community as those communities have lacked appropriate training in how to inspect stoves.  Safety inspections of wood stoves are supposed to be required for all stoves, whether they are primary or just occasional heaters for DOE funded programs, such as for low-income homes covered by WAP – the Weatherization Assistance Program.

Download visual guide here

This easy-to-use guide provides photos of the most common safety issues found in wood stoves that should be checked by energy auditors - as well as other energy and hearth professionals.  It can also be useful for homeowners.  Coming soon is a checklist that will indicate the status of each item and whether it needs repair.  The guide is broken down into what needs to be checked on the exterior of the stove, the interior of the stove, the exterior of the house - and many special circumstances.  Some items are in grey areas of what an energy auditor is responsible for checking - such as the storage and moisture of the firewood - and we encourage states and counties with high rates of wood stove installations to engage in a more expansive audit.

The problem is that there is little evidence to indicate that stoves are being inspected in a meaningful and consistent way within many WAP programs.  Most states use forms that provide many options to add detail about the inspection of a furnace, but little or none for wood stoves.  Some states list wood stoves as a heating appliance and a few states, like Idaho, ask if the stove is “operable, failing or inoperable.”  Furnaces on the other hand are turned on and have their flue gases tested, producing a written record on CO, PM, temperature efficiency and draft.  This provides useful, objective indicators of the health of the furnace or boiler.  There is no corollary data input options for wood stoves that would provide a written record showing the stove had received a meaningful or even minimal inspection.

 

In recent weeks, AGH did PowerPoint presentations to two important stakeholder groups: the DOE WAP Training Consortium and the National Residential Wood Smoke Workgroup.  Both of

Download PowerPoint here.

these presentations were very productive and led to substantive follow-up work with many of the attendees.  Kelly Cutchin who heads up the WAP Training Consortium has been particularly helpful as AGH navigates the bureaucracy that surrounds WAP standards, update, trainings, etc.  

 

But while this project has gained a lot of traction and improvements are happening, we are still far away from our goal: changing the standards that the DOE uses to approve state work specification documents that have minimal attention to wood stoves.  Most states are not living up to DOE requirements that all heating systems be inspected and repaired, as needed, or possibly replaced. One problem is that DOE regulations provide far more specificity about fossil fuel furnaces and boilers. For example, “WPN 19-4 Revised Energy Audit Attachments”, a key guidance document for the Weatherization Program, mentions boilers 19 times, furnaces 21 times, and wood stoves only 1 time. The result permeates the inspections and attention that each heater receives throughout the value chain. Thus, in the sections about repairing heating equipment, there is no guidance about how to repair a stove, while there is a long list of things relevant to boilers and furnaces. This continues year after year, despite the fact that there are more wood stoves than residential boilers in the United States (around 9 million homes are heated with oil, gas and propane boilers, while 10.1 million wood stoves provide primary or secondary heat nationwide). 

There are plausible explanations for why WAP materials often have far more detail about inspecting and repairing furnaces compared to wood stoves. First, wood stoves are more often than not, a secondary heater, where furnaces are almost always primary heaters. Second, wood stoves are very infrequent in urban areas and in southern states. And third, there could be an implicit bias against wood stoves by agency officials who view them as a relic of the past and underestimate their numbers, safety issues and their importance for the rural poor.

The integration of wood heaters more fully in the WAP program ultimately should include changes to state “Standard Work Specifications” (SWS) documents, which are updated every 5 years to assure they reflect industry-accepted practices. Significant updates in the area of combustion safety occurred in the last 5 years but it is unclear if wood stoves were included in any significant way.

 

Sometimes, WAP documents say little more than a stove should be replaced if it shows “structural failure.” Some states seem to interpret that as having a crack in the heat exchanger, which in the case of a wood stove means a crack in the body of the stove. Maine is more restrictive and says replacement is "allowed only when there is a crack in the heat exchanger than may cause a carbon monoxide problem or a fire danger."  Montana is unique and at the opposite extreme where non-EPA certified stoves are considered de facto "unsafe for program purposes." 

 

Changes in these DOE funded programs will also influence the way that states, utilities and private companies conduct energy audits.  When AGH polled its supporters who have had energy audits recently, a majority said their wood or pellet stove was completely ignored.  Considering so many wood stoves are self-installed, this oversight is ripe for change.

 

Many thanks to everyone who has been working with AGH on his project, and special thanks to the CSIA, EPA and the WAP Trainers Consortium.

For further reading:

Common Problems – and Solutions – for Self-Installed Wood Stoves, Oct. 2024

Identifying Barriers to Integrating Wood Stoves in WAP Energy Audits and Weatherization Programs, Oct. 2024

Wood stove inclusive energy audit standards still missing in America, Aug. 2021
BPI Energy Auditing Standards Open for Public Comment, Oct. 2013
Unsafe Wood Stoves Routinely Overlooked During Energy Audits, May 2012

Wood stove inclusive energy audit standards still missing in America

By John Ackerly and Caroline Solomon 

The DOE's weatherization program for
low income households is the largest 
weatherization in the US

In 1988, when wood stoves were at the height of their popularity in the U.S., the Department of Energy issued a memo clarifying that wood stoves in DOE-funded energy audits and weatherization programs should be included and could be replaced.  But, they also said that “DOE considers wood stoves to be a unique measure… and …  it is the energy audit which is the driving force for determining whether a wood stove should be replaced.”

 

This was a victory for the many states that wanted to use DOE funding to repair and possibly replace old wood stoves that pose health, safety, and environmental risks. However, fast forward to today – 33 years later – and wood stoves remain a “unique measure” and are often overlooked in DOE funded energy audits. Nearly 10 million homes have been audited and weatherized with DOE funding and all homes with gas furnaces, for example, had those furnaces inspected for safety – and efficiency.  But there is no consistency or uniformity for how a stove should be inspected or when it and how it should be repaired or replaced.  To understand how and when the breakdown happened, we went back in time and dug into countless documents, reports, and energy audit standards. Here’s what we found out.

 

In 2012, we wrote a blog about how energy audits were routinely overlooking wood stoves, many of which were unsafe, dirty, and hazardous. At that time, many auditing standards, including those approved by the Department of Energy’s Weatherization Assistance Program (WAP), did not contain guidelines for how energy auditors should inspect wood stoves while in a home.

 

In 2013, AGH worked with the Building Performance Institute (BPI), who developed long-overdue standards on safety inspections for wood stoves. But the standards were voluntary, and eight years later, we found that virtually no one is using them, and most energy audit companies don’t even know they exist. AGH continued to work with EPA staff, who were also eager to see stoves consistently included in energy audits, but our impact was minimal.

 

In the summer of 2021, AGH turned again to the DOE, who runs the nation’s largest auditing programs through their Weatherization Assistance Program (WAP). Senior WAP officials were very accessible and open to discussing the issue, and pointed to their regulatory language, which dictates that “all heating systems, regardless of type” be inspected, repaired if necessary, and even replaced under some circumstances. DOE has to approve each of the audit programs used with their funding. So far, so good.

 

Things began to unravel when we dug into hundreds of documents, from national audit program notices to state weatherization plans to work specification field guides to local application forms and field data collection forms. The problem is not that wood stoves are excluded, but that very few states have any detail about how to inspect a wood stove. Usually, documents from the DOE all the way down to a county audit program have all of the details about inspecting, repairing, and reporting on a gas furnace, for example. Boilers are often well-described, but details dry up very quickly when it comes to wood stoves. The result is a patchwork of state programs, with some meeting DOE regulations, and others falling far short.

 

The problem also involves national auditing tools, approved by DOE.  NEAT is the most popular energy audit tool and is used in about 35 states.  It addresses wood stoves in its Health & Safety audit mainly as an indoor smoke issue.  It references inadequate floor protection and oversizing but does not mention clearance to combustibles or cracks in the firebox or glass.  Adding to the issue is that DOE published Standards for Conformance that includes a lengthy list of “tune-ups/efficiency improvements” for furnaces and boilers, but not even one for wood stoves.

 

Far from being a unusual heating device, wood stove
are more common that many other heaters in the US

If wood stoves were just a tiny fraction of heaters, like coal stoves are, overlooking them would make more sense.  But there are more wood stoves in America than there are oil boilers, oil furnaces or propane furnaces, and almost as many as gas boilers.  Some states, like Maine, New Hampshire and Wisconsin have provided extensive guidance around wood and pellet stoves.  Oddly, Oregon, a state with far more problems with wood smoke, has little guidance, resulting in fewer inspections, repairs and replacements of old wood stoves.

 

One distinct feature of wood stoves makes them particularly in need of safety check-ups: unlike other heating systems, many if not most wood stoves are homeowner-installed, and these stoves are often not up to code.

 

AGH is now midstream in our effort to work with DOE officials, DOE contractors, state officials, and others to get feedback on how to correct this problem. One DOE contractor who is deeply involved in the matter says she thinks we can begin making substantive changes quickly, but systemic problems like this, take years to address. 

 

We are currently preparing a report that (1) assesses audit programs approved by the DOE, (2) assesses state Standard Work Specification guides and (3) Assesses how local WAP programs collect information about heating systems. Stay tuned for more in-depth coverage of this issue.

 

We expect our report will be extremely helpful to the DOE who could update guidance to ensure a minimum level of stove inspections to establish more uniformity how stoves are inspected and what repairs should be considered.  The report should also be helpful for states that want to address the safety and performance of old wood stoves.

 

We want to thank the scores of people who have helped address this problem, starting with folks at BPI who worked on it back in 2012 and 2013, to all the federal, state, and local WAP officials we interviewed this summer.

 

And thanks to all our supporters who provided data about how and whether their stove was included in their energy audits. If you have had an audit recently, please share the results with us (info@forgreenheat.org).

 

John Ackerly is President of the Alliance for Green Heat and Caroline Solomon is an AGH fellow.