The healthiest ways to light up a fireplace

When Trystan Bass first stepped into her 1920s-era home in Oakland, Calif., she immediately noticed the focal point of the living room: a floor-to-ceiling wood-burning fireplace.

"It's gorgeous and one of the reasons I bought the house," said Bass, 53. "But I was never going to light a fire in it."

No matter the type of fireplace, whether it's wood-burning, pellet-burning, natural gas or electric, using one typically generates some amount of greenhouse gases and other emissions that can be damaging to the environment and human health.

To avoid these effects, Bass said she recently bought flameless battery-powered candles and placed them inside her fireplace. "It's exactly the effect with none of the muss and fuss," she said.

If you want to light up a real fire or at least mimic the experience, here's what experts say you need to know about commonly available fireplaces and how you can curb emissions from using them this winter.

A traditional open wood-burning fireplace "emits the greatest amount of pollution and is typically the least efficient," according to a spokesperson with the Environmental Protection Agency. Most of the heat goes out through the chimney, making it a poor way to warm a home.

Burning logs of wood in an open fireplace also can cause air-quality problems. Experts say smoke from residential wood burning is a major cause of poor outdoor and indoor air quality in many areas across the country, particularly during winter months. Wood-burning by households can produce more than 300,000 tons per year of fine particulate matter, or PM 2.5, which is a hazardous air pollutant, according to the EPA's 2017 National Emissions Inventory. In comparison, residential use of natural gas generates just over 4,000 tons per year of PM 2.5.

"If you’re in a neighborhood where there's one smoky fire burning, you’ll notice that from blocks around," said Bill Magavern, the policy director at the Coalition for Clean Air, a California-based nonprofit organization that advocates healthy air. "Just one fire can be enough, unfortunately, to dirty the air in a whole community."

Wood smoke contains carbon monoxide and other toxins, as well as fine particles, which can trigger or worsen certain health conditions. Breathing in particulate matter is associated with asthma and serious heart problems, including irregular heart rhythms, heart attacks, strokes and heart failure.

How to burn a cleaner wood fire:

To reduce the amount of potentially harmful byproducts released, experts say it's critical that your wood fire is burning well.

If the carbon contained in wood is burned at peak efficiency, it should turn into carbon dioxide, said Anna Karion, a research scientist who works in the National Institute of Standards and Technology's greenhouse gas measurements program. But, she noted, wood-burning fireplaces generally can't create the ideal combustion conditions to produce only carbon dioxide. Using an inefficient fuel or burning in poorly ventilated conditions also can lead to more of the carbon being emitted as carbon monoxide or methane, she said.

"Either way, you’re emitting the carbon, but what the impact is going to be of that molecule depends on this efficiency of the combustion," Karion said. "If it's all being combusted directly to CO2, that's sort of like the perfect case."

Deadly air pollutant ‘disproportionately and systematically’ harms Americans of color, study finds

The hotter a fire burns, the cleaner it is, said John Crouch, the director of public affairs at the Hearth, Patio and Barbecue Association, an industry group.

For those planning to light wood fires, Crouch and other experts emphasized the importance of using dry wood that has been seasoned and split well. Properly dried wood should have a moisture reading of 20 percent or less, according to the EPA. You can buy moisture meters at hardware stores and online. The EPA provides online resources and guidance about burning wood through its "Burn Wise" program.

If you’re lighting only an occasional fire, you might want to use a "wood/wax fire log," which tends to be more environmentally friendly than regular wood, Crouch said. These logs are typically a mix of sawdust and some candle wax intended for use in fireplaces. They should not be used in wood stoves, he said.

"One of the reasons fire logs have lower emissions is simply because the paraffin mixed in the sawdust helps keep the fire temperature hotter, so it does a better job of breaking down the particulates," he said.

Avoid burning garbage, plastic, glossy paper or wood that has been treated, Magavern said. "Then you get chemical toxins that go beyond the ones that you find in natural wood."

If you light a fire and notice a lot of smoke coming out of your chimney, "that's a bad sign," Magavern said.

"A properly burning fire should only be giving off a thin wisp of white steam after a half-hour or so."

Another way to increase efficiency and reduce wood smoke pollution is to install a wood or pellet-burning stove insert, according to the EPA, which certifies these appliances. Generally, wood or pellet-burning stoves also allow users to better control the heat.

Designed to be installed within the firebox of an existing fireplace, an insert may be the appropriate option if you’re trying to heat large portions of a house or, in some cases, an entire home, Crouch said. Wood or pellet stoves also can be free-standing.

"One of the weaknesses of an open fireplace is things just move along too fast" and there isn't enough time for the fire to finish burning everything, he said.

Stoves and fireplace inserts certified by the EPA are supposed to be designed with better insulation and improved air flow, meaning "more of these gases and particles are burned inside the stove, resulting in less smoke," according to the agency. In a 2013 publication, the EPA estimated that 65 percent, or about 7.8 million, of the wood stoves in the United States were older, inefficient devices.

"Changing out one old, dirty, inefficient wood stove is equivalent to the PM 2.5 pollution reduction of taking five old diesel buses off the road," the EPA noted.

But the EPA's certification of wood stoves has come under scrutiny after a report published last year by the Northeast States for Coordinated Air Use Management (NESCAUM), a group of state air-quality regulators. After reviewing around 250 certified wood heaters, the report found "a systemic failure of the entire certification process, including EPA's oversight and enforcement of its requirements."

A spokesperson for the EPA said the agency is "working to address the concerns raised by the 2021 NESCAUM report."

A fireplace insert can help ensure that your heat doesn't go up the chimney

Experts say pellet-burning stove inserts, which also can be certified by the EPA, are another option — although they typically require electricity to run. These stoves use pellets made of compressed wood or other biomass as fuel and are generally cleaner and more efficient than wood stoves, according to the EPA.

However, environmental and social concerns are being raised about pellets and how they’re manufactured. A report from the Rachel Carson Council, a national environmental group, criticized the wood pellet industry, calling attention to impacts such as deforestation and the increased risk of health problems for communities surrounding production facilities releasing pollution. The report also noted that "burning wood pellets releases 65% more CO2 than coal per megawatt hour."

For the most part, natural gas fireplaces, which also include gas stove inserts or gas logs, are "going to burn a lot cleaner and safer than wood and other types of fuels," said Brett Little, the education manager at the GreenHome Institute, a nonprofit organization. According to the EPA, gas logs are generally designed for decorative purposes. If you’re looking to provide heat for a room, installing a gas stove into an open fireplace might be the better choice.

Burning natural gas "has virtually no particulate emissions," Crouch added. But it does produce pollutants such as nitrogen dioxide and carbon monoxide, the EPA spokesperson said. The agency recommends avoiding the use of unvented gas fireplaces, including gas logs and gas stoves.

Some experts say it's also important to take into account the broader environmental footprint of the energy source. A significant proportion of natural gas in the United States is procured through a controversial extraction process known as fracking. And since natural gas is mainly methane, any leak can release the potent greenhouse gas into the air.

"The pellet stove is not leaking methane into the atmosphere, whereas the natural gas system is contributing to leaking methane all over and it leaks in people's homes, too," Little said.

Methane leaks offset much of the climate change benefits of natural gas, study says

Regardless of whether you have a gas or wood fireplace, the EPA urges proper installation and maintenance. "Blocked, leaking or damaged chimneys or flues can release harmful combustion gases and particles and even fatal concentrations of carbon monoxide," the EPA spokesperson said. Chimneys and vents should be professionally inspected each year.

If you primarily want a fireplace for aesthetics, Little encourages people to ask one question: "Is it necessary to burn anything to do that?"

Electric fireplaces, many of which are outfitted with resistance heaters, can provide the look and feel of a wood-burning or gas fireplace without the on-site emissions concerns.

"Why put out carbon emissions and risk your health and your safety when you can just have something that is very aesthetically pleasing and works very well taking the electric approach?" Little said.

But Little and other experts note the environmental impact of these fireplaces depends largely on how the electricity is generated. "You have to understand your grid and what your grid is made out of at the time," Little said.

"You might still be burning gas indirectly through the power plant," he added. "But what we know is the grid is getting cleaner and cleaner and cleaner every year and eventually it’ll be all renewable."

Sign up for the latest news about climate change, energy and the environment, delivered every Thursday