Direct-vent fireplaces Niceville FL
There’s nothing like a warm fire on a cold day. The ambiance can’t be beat — but unfortunately, as you’re sitting in front of that cozy wood-burning fireplace, it’s greedily consuming your energy dollars.
According to the Department of Energy, traditional fireplaces send as much as 300 cubic feet of heated interior air up the chimney each minute. “Your fireplace will suck all of the [conditioned] air out of your house in a little over an hour,” says Tim Rethlake, vice president of new construction sales growth with Hearth & Home Technologies, of an average 1,800-square-foot home. That means your heating system will have to run more often to warm your house, sending your utility bills soaring.
Experts note that traditional fireplaces can also have a negative affect on air quality, both indoors and outdoors. Wood-burning fireplaces are notorious for causing respiratory ailments by emitting fine particulates, which settle deep in the lungs. According to the Environmental Protection Agency, smoke from fireplaces and woodstoves is the single largest source of outdoor air pollution in some residential areas. During heating seasons, wood smoke can account for as much as 80 percent of the particulate matter (PM) emissions around residences. That’s why communities like Mill Valley, Calif., prohibit the use of wood-burning fireplaces or stoves on days when local air quality is a concern.
What’s more, in some newer homes, wood-burning fireplaces often won’t function properly. Tight new construction practices mean less air infiltration in the home, so there’s less airflow to draw on to ensure optimal operation of the fireplace. Without enough air to “breathe,” the fireplace emissions can backdraft into the home more easily.
So what’s to be done? Fortunately, homeowners have a number of good options, and one of the best is to retrofit a direct-vent gas fireplace insert into the existing fireplace opening.
Bringing Outside Air In
Direct-vent fireplaces take the guesswork out of safety and efficiency because they don’t use conditioned air for combustion, as traditional fireplaces do — and return no combustion air to the home. Instead, direct-vent fireplaces use two flexible metal tubes that vent directly to the outside. One tube brings fresh outside air into the fireplace, while the other vents combustion gases out of the home.
As a result, direct-vent fireplace inserts operate much more efficiently than traditional fireplaces, and can provide zone heating in areas frequently used by your family, enabling you to turn down your central heating system.
Inside a direct-vent fireplace there are two boxes — a sealed inner combustion firebox and the outer cabinet. The firebox, which is constructed of metal or ceramic fiber, provides superior heating efficiency while preventing spillage of combustion gases into the home. It has a passageway around it that allows for convection of hot air between the inner firebox and the outer cabinet. The combustion is so efficient that very little heat is radiated to the walls of the home, so the unit can be installed without the need for an extensive masonry hearth or chimney.
Self-cleaning glass doors insulate the firebox on the front, and appropriate insulation material insulates it from the sides and back of the unit. In some units, a convection fan helps circulate air through the passage between the inner firebox and outer cabinet.
Many direct-vent fireplaces are extremely energy efficient, with AFUE (annual fuel utilization efficiency) ratings in the high 70s. An AFUE rating of 80, for example, indicates that a system converts 80 percent of the fuel to heat. For comparison, a traditional fireplace is only about 10 percent efficient at converting wood to heat and delivering it to a room.
The resulting heat capacity for most direct-vent units is between 20,000 and 40,000 BTUs per hour. That’s more than enough to heat a large room. In fact, you could heat a small home with a 40,000-BTU unit.
The cost for direct-vent fireplaces ranges from about $1,000 to 5,000, with labor as little as $500 for basic installation. Extensive custom surround work can push the cost over $5,000.
When installed into an existing fireplace opening, the direct-vent unit’s intake and exhaust tubes can be run up the existing chimney flue, provided there is enough room for the diameter of the tubes. The tubes connect to a chimney cap at the top to keep the two channels separate. Some systems put one tube inside of the other, creating a smaller-diameter tube that can be installed in a tight space.
In some older homes, alterations made when adding a forced air heating and cooling system have resulted in the “confiscation” of the chimney, note Karen and Michael Duke, owners of the Victorian Fireplace Shop in Richmond, Va. As a result, the chimney is unavailable for use with a direct-vent unit. “Just because there’s a fireplace doesn’t mean there’s a chimney available to service it,” says Karen Duke.
In other homes, chimneys can have a significant number of turns and bends. In these cases, the best option is to vent the inlet and outlet tubes directly through the exterior wall — horizontally out a hole cut behind the fireplace. This may result in the need to restore and repair masonry damage to the existing fireplace. On the outside of the house, the intake and exhaust tubes connect to a specially designed termination cap.
When installing a direct-vent fireplace insert, keep in mind that there are limits set by codes and manufacturers for how far you can run the tubes to reach the outside and vent the unit. In some unusual cases, it may not be possible to “legally” vent the unit. Check with a local retailer or installer to ensure safe and proper installation.
Beyond the Basics
When purchasing and installing a direct-vent gas fireplace insert, there are a number of other factors homeowners should keep in mind, including the following:
Gas and electric lines. Naturally, you’ll need a natural gas or propane line to your home to fuel the direct-vent fireplace, and in some cases you’ll also need electricity, since many units are equipped with a fan to circulate heat out into the room. To get around the need for electricity, consider a unit with a ceramic fiber firebox, which doesn’t require a fan. Ceramic fiber transfers heat less quickly than metal, so the heat is held in the firebox longer and naturally convects into the room.
Existing fireplace dimensions. “The biggest challenge with a fireplace insert is the dimension of the existing fireplace,” says Rethlake, “If it’s an old masonry-style fireplace, like the ones you can virtually walk into, there’s no problem. But if the home is less than 20 years old, the fireplaces can be much smaller. The question is whether the insert can physically fit into the existing opening.” Again, a retailer or authorized installer can help you select a direct-vent unit with the proper dimensions for your particular situation.
Aesthetic issues. More than likely, you’ll be able to find an insert that fits your fireplace opening, but the challenge is often finding one with a metal faceplate that blends naturally with the existing fireplace. Some of these metal surrounds are quite attractive but may not be appropriate for every application, especially if they cover the beauty of your fireplace’s natural stone. In these cases, consider a unit that has a more natural ceramic fiber surround option, which can be custom-fitted to your fireplace.
Small viewing areas. Tex McLeod, housing specialist and former manager of the Hearth, Patio and Barbecue Association of Canada, points out that many homeowners are surprised with the smaller viewing areas of direct-vent gas fireplaces, when compared to the original fireplace opening. “It’s like putting a new window in an old window frame,” McLeod says. “You cut down on the size of the opening somewhat, but newer products have become more aesthetically pleasing.” Also, he notes, it’s important to keep in mind that a smaller unit is also a more efficient one.
Finally, as noted earlier, it’s best to have a direct-vent fireplace insert installed by a certified professional. In many cases, when installing a direct-vent unit, it will be necessary to make alterations to an existing fireplace or chimney, and alterations made by an inexperienced installer can cause safety and indoor air quality concerns, McLeod notes. To find a certified installer in your area, visit the National Fireplace Institute’s website at www.nficertified.org .
A direct-vent gas fireplace insert is an attractive alternative to a drafty, high-maintenance existing wood-burning or older gas-burning fireplace. A qualified installer, some of the cool new products available on the market and a little savvy to ensure you select the right unit for your home will leave you warm this winter, and reduce your energy bills as well.
Stacy Hunt is a writer and consultant in the sustainable, energy and environmental building industries. She lives in Pittsburgh, Pa. For more information, visit www.stacyhunt.net .