Chimney Liner Pro

If you have a wood burning fireplace inside your home, you can probably do some simple things to your fireplace and chimney to improve your home’s energy efficiency. Some of these are free and will give you an instant return on your time investment, while others can cost a bit of money. Even the things you can spend money on, though, will give you a much better return on your investment than you can get from a certificate of deposit at your local bank. The fact is that most wood burning fireplaces are energy hogs. When you have a fire burning in a standard fireplace, it is likely that your fireplace and chimney are sucking more cold air into your house than the heat from the fire is adding back to your house. Also, when you are not burning a fire, your chimney is probably acting like a long straw sucking warm air out and letting cold air back in.

To get some idea of how much your present fireplace and chimney system is costing you, pick a day when it is really cold outside and you aren’t burning a fire and hold your hand out in front of your fireplace or reach inside the firebox. Do you feel a cold draft falling out of the chimney? If you do, the obvious thing to check first is to make sure your damper is closed. If you still feel a draft with the damper closed, and you are likely to, it is because the metal damper parts have become warped and worn over the years and don’t seal well, anymore, so you have cold air freely falling down your chimney as if you had a gaping hole in your ceiling. A relatively inexpensive investment you can make is to install a Seal Tight Chimney Damper or Energy Top Chimney Damper on top of your chimney. These devices seal off the top of your flue when you are not using your fireplace and prevent heat loss through your chimney. They have a control rod that extends down to your fireplace so you can open and close the damper from inside instead of having to climb on your roof to remove any other kind of cover you may put on your chimney.

One of the best ways to address the problem of an inefficient fireplace is to install a wood burning insert inside your fireplace along with a flexible M-Flex stainless steel chimney liner. A modern wood burning insert is designed for high efficiency, so it actually releases far more heat back into your house than it sucks cold air in to feed the fire. The chimney liner also insulates your flue so you get better draft into your insert and more complete combustion of the fuel. An uninsulated flue lets smoke and combustion gases cool off by the time they reach the top of the chimney, which weakens your chimney’s draft, so insulating the flue helps keep the gases hot all the way out of your house.

You can improve your home’s energy efficiency with relatively inexpensive passive measures like installing a better damper, or you can make a fairly large investment in a wood burning insert to make your fireplace much more efficient. You will burn less wood and get more heat, so your savings in firewood costs will pay for the insert over time, probably at a rate much better than the less than one percent you can make on your money in a savings account.

Bookmark It

Hide Sites

To measure for a chimney liner kit you need to determine the physical dimensions of your chimney as well as the specific requirements for the type of appliance you are hooking the liner to. A chimney liner kit that will serve a fireplace needs to have the largest diameter pipe that will fit inside your flue, whereas the liner size required for other fuel burning appliances will be determined by the manufacturer’s specifications and local safety codes.

The basic measurements you need before you select a chimney liner kit are the height of your chimney and the inside dimensions of your existing flue. From the top of your chimney, measure to the top of the fireplace smoke chamber or the connection point for your woodstove or furnace. You can use a long flexible tape measure or tie a bolt or other weight to a string and lower it down your flue to the point where the bottom of the liner will be connected and then measure the string to determine the chimney height. Measure the inside dimensions of the clay tile liner (if your chimney is lined with tiles) at the top of the flue.

For a fireplace, you should have a liner with a cross sectional area no less than one tenth of the area of the fireplace opening. This ten to one ratio is a rule of thumb that can vary depending upon the height of the chimney and other factors. If the liner diameter is too small, your fireplace will not draw well, resulting in smoky fires and smoke-filled rooms. If the size of liner that you need for your fireplace is too large to fit inside your existing flue, you may need to repair your clay tile liner rather than inserting a steel liner inside it. An alternative would be to modify the opening of your fireplace to make its effective area smaller, perhaps by installing doors with adjustable airways or by installing a wood burning insert.

To measure for a chimney liner kit that will serve a wood stove, furnace, hot water heater or other fuel burning appliance, you should follow the manufacturer’s specifications. The inside diameter of the vent opening on the appliance will determine the ideal diameter of your chimney liner. It is a good idea, and a code requirement in some places, to insulate the outside of a chimney liner, so you will need to size your liner to allow space for insulation between the outside of the liner and the inside of the flue. An insulated chimney liner will keep the exhaust gases hotter all the way out of the house and minimize condensation of creosote and acidic water inside the chimney.

Getting good measurements for a chimney liner kit before you buy will save a lot of time and frustration. A properly sized and installed liner will make your house safer and more energy efficient while extending the life of your chimney.

Bookmark It

Hide Sites

If your flue vents directly into the air at the top of your chimney, there are a lot of reasons why you should install a chimney cap. A chimney cap covers the flue, allowing enough space for smoke and gases to escape unimpeded. It keeps snow and rain out of the flue and off the masonry crown and may be screened to keep trash and small animals out. The type of chimney cap you choose will depend upon your chimney configuration, the functions you want the cap to perform, and your individual decorating preference.

Chimney caps are made from several different metals, including copper, aluminum, steel painted black and stainless steel. The top cover is wide enough to keep precipitation off of the chimney top. The open spaces around the sides are usually enclosed with screen or course mesh. This acts as a spark arrestor as well as keeping leaves and squirrels, bats, birds and other small animals out of your chimney and out of your house. Most chimney caps are made of corrosion resistant metals or have corrosion resistant finishes, so you can choose the metal and color that best fits your exterior home decoration.

Chimney caps are manufactured with different bases to fit the type of flue you have. If you have a cylindrical metal chimney liner, you can find caps with round bases to fit the top of the liner. If your chimney has a rectangular tile flue liner, you can buy a chimney cap with a rectangular base that fits over the outside of the top tile. If you have a chimney with multiple flue openings, you can get a chimney cap that is sized to fit over all of them, or you can buy individual caps for each flue.

A basic chimney cap protects the chimney from precipitation and keeps things from falling down the chimney. In some cases the geometry of a basic cap also improves the draft of the chimney, although soot buildup on the screened openings can impede draft. For windy locations, special chimney caps that are designed to create a vacuum inside the flue when it is windy can help to alleviate down drafting problems.

A chimney cap that includes a top sealing damper is an effective way to improve your home’s energy efficiency. Old metal fireplace dampers that don’t seal well even when they are closed tightly let cold air infiltrate the house when a fire is not burning in the fireplace. A top sealing damper chimney cap has a cable that runs inside the flue to a lever that can open and close the damper from inside the house. With the damper closed, you will immediately notice fewer cold drafts in your room.

The variety of ready made chimney caps on the market should let you find what you are looking for by shopping online or at your local chimney supply store. If you have a special situation that lend itself to standard solutions, most chimney cap manufacturers can build a custom cap exactly to your specifications for a reasonable price.

Bookmark It

Hide Sites

Modern houses and other buildings usually have prefabricated metal fireplaces and flues, rather than traditional brick and mortar fireplaces with brick chimneys surrounding clay tile flues. The frame that is built around a modern prefabricated chimney is called a chase. The chase is usually constructed of wood framing covered with a skin of siding, masonry or stucco. In high quality construction, the space inside the chase outside the flue will be insulated. The chase cover is the fitting that goes over the top of the chase with a hole in the middle to fit around the top of the flue.

Many chase covers are manufactured from galvanized steel, which will resist rust and corrosion as long as they are painted and not subjected to extreme temperature conditions. Many are poorly designed with flat tops that collect rain and snow that does not quickly run off. Heat from the combustion gases coming up the chimney, exposure to intense summer sunlight and corrosive standing water all contribute to peeling paint and rust in cheap galvanized chase covers.

When a chase cover shows rust, or when a homeowner notices rusty stains down the side of the chase, it is time to replace it with a new and higher quality cover. Once a cover begins to rust, it will quickly develop holes that let water leak into the chase and down the flue. This water infiltration can cause mold growth inside the chimney and nearby structural parts of the house, it can damage sheetrock and ceilings, it can compromise the insulation, and it can lead to corrosion inside the flue.

A high quality replacement chase cover for a chimney is a wise investment that will easily pay for itself in reduced future home maintenance expenses. Chase covers can be fabricated from corrosion resistant materials that will last many decades even under the extreme conditions at the top of a chimney. Stainless steel and copper are popular materials for chase covers that can be purchased with lifetime warranties.

You may be able to find off the shelf chase covers that fit your needs by shopping online or at your local hardware store, but you can also have a chase cover custom made at a reasonable cost. A high quality chase cover should be slightly domed or arched on top to encourage water runoff and it should be made of stainless steel, copper, bronze or some other corrosion resistant metal.

You can get a chase cover with a chimney cap already built into it in one piece, or you can buy a simple chase cover to seal your chase and around your flue and then select a separate chimney cap to fit your home decorating taste. Your chase cover does not have to be a simple cap with a hole for the flue. Some custom chase covers are decorative additions to chimney tops in addition to being an integral part of a safe and efficient home energy system.

Bookmark It

Hide Sites

If you look online at a chimney products site, you will see that you can choose from a variety of different materials for a chimney liner. You will also see that metal chimney liners come in convenient kits, complete with a flexible metal liner and all the necessary fittings to complete your installation. You may be tempted to order an aluminum liner kit, because it is a lot cheaper than stainless steel, or you may want to order a rigid stainless steel liner kit because it is also much cheaper than a flexible stainless steel kit. But, before you buy, you need to be sure you are getting the correct liner for your particular application.

In order to be completely sure you are getting the right product, it would be wise to consult with a chimney specialist or your local building codes to see what the industry standard for your system is. In general, you will need a stainless steel liner for any application that needs to withstand high heat or corrosive flue gases. You may be able to use an inexpensive rigid liner, but this will make sense only if you have a flue that is vertical from top to bottom with no offset, or bends, along the way. The labor expense and parts cost involved in connecting special fittings to a rigid liner to make bends in the flue will likely offset the higher cost of a flexible liner.

The only type of appliance you want to attach an aluminum liner to is a low efficiency gas or oil burning boiler or furnace or water heater. The combustion gases leaving a fuel burning appliance contain carbon dioxide and water, and possibly some other compounds, which tend to condense inside a cool flue and cause corrosion damage. A low efficiency appliance wastes a lot of heat by sending very hot gases up the flue, which are usually hot enough to not condense before they are exhausted outside. That is why an aluminum liner is adequate for this type of installation.

If your application will be exhausting lower temperature gases which are likely to condense before they leave the chimney, then you need to choose an appropriate grade of stainless steel for your flexible liner. High efficiency furnaces and other appliances emit lower temperature flue gases, so corrosive condensation is a problem if you don’t have the right type of flue liner. For applications such as woodstoves and fireplaces, you have the potential for very high temperatures at times, and creosote and corrosive chemicals condensation at other times (especially when you cool the fire by constricting the damper to keep hot coals all night long). So, you will need a stainless steel liner to avoid corrosion and to withstand high temperatures in the event of a chimney fire ignited by creosote in the flue.

When planning your chimney liner installation, always buy materials that are safe for the use you need them for. Flexible stainless steel liners may cost more than other materials, but they will save you money in the long run and keep your house safer if they are the type of liner you need.

Bookmark It

Hide Sites

The chimney liner inside your flue is one of the most critical parts of your chimney system, so it is important to keep it maintained properly. The chimney liner seals the flue walls so that smoke and other combustion products cannot leak into the external chimney structure or attached building before they are exhausted out the top of the chimney. If your chimney liner leaks, it can cause problems ranging from damage to the chimney masonry structure to carbon monoxide buildup inside your house. The clay tile liners that were commonly installed in brick chimneys after the 1940’s will last for several decades unless they are damaged by external water infiltration or structural shifting. Metal liners will usually last a very long time without failing, unless they are made of an alloy that is unsuitable for the application they are installed for.

Combustion products from burning fuels contain carbon dioxide and water, plus other impurities that can condense into highly corrosive compounds under the right temperature conditions. This corrosive condensation adheres to the walls of the flue and eventually damages mortar between tile or bricks, and can eat holes in metal liners if they are not made of the right alloys. Creosote is one of the most common combustion products from burning wood. Creosote condenses inside the flue, especially near the top where the chimney is coldest, to form thick black gooey or crystalline masses that impede air flow up the chimney and represent a serious fire hazard.

In order to maintain your chimney liner properly, you should have it cleaned and inspected at least once a year by a chimney professional. If the inspection reveals damage to the walls of your chimney liner, you will need to have appropriate repairs done to keep your flue operating safely. If a clay liner has tiles broken or missing, or cracks in the parging between tiles, you may need to have the liner replaced, or have a flexible metal liner inserted inside it. If your metal liner develops leaks, it will probably have to be replaced.

There are some things you can do to maintain your chimney system to avoid future large repair costs. Install a chimney cap on top of your flu to keep rain, snow and animals out of your flue. Apply Crown Seal to the masonry crown on top of your chimney and use Crack Magic Crack Sealant to repair any external damage to bricks or mortar on your chimney. These will prevent infiltration of water from outside your chimney, minimizing freeze/thaw damage and other problems caused by moisture. Use dry wood to burn clean, hot fires to avoid creosote buildup. A carefully maintained chimney and chimney liner will give you many years of safe, enjoyable use.

Bookmark It

Hide Sites

Your masonry chimney is vulnerable to attack by water from both the inside and the outside, but there are steps you can take to protect it. The outside of your chimney is exposed to weather all year round. Rain and snow can penetrate cracks in the mortar between bricks or in the mortar cap on top of the chimney. Temperature fluctuations in cold weather will cause water trapped in tiny cracks to expand and contract in a freeze/thaw cycle which can eventually tear your chimney apart. You can protect your chimney from this external aqueous assault by sealing the exterior surfaces and filling cracks with products such as Crown Seal and Crack Magic Crack Sealant. You can also install a chimney cap over the top of your chimney to keep rain and snow from falling inside your flue and on top of the mortar cap. A stainless steel chimney cap not only covers the flue, but it has a screen mesh that acts as a spark arrestor and keeps birds, squirrels, bats and other unwanted visitors out of your house.

Your chimney can be attacked by water from the inside, where it might do more damage to the structure than external moisture. Besides having rain and snow enter your flue from the top, water vapor is carried up the chimney along with other combustion products to be vented to the outside. As the combustion gases rise up the chimney, they will cool enough to condense onto the inside walls of the flue. Water vapor condensing with carbon dioxide and other combustion compounds is extremely acidic and can eat away at the mortar between bricks or clay liner tiles, eventually causes cracks that can leak dangerous gases into your house. One solution to this problem is to install a flexible stainless steel chimney liner inside your flue. The new liner will physically separate water and other combustion products from the masonry chimney structure, so corrosive effects of water infiltration are stopped immediately. A flexible steel liner offers other advantages besides preventing corrosive water damage. By insulating the inside of the flue, the liner keeps combustion gases hotter as they rise up the chimney, so less condensation of water, soot, and creosote occurs. The round cross section of the chimney liner also lets gases flow easier up the chimney than they do in a square flue. This smoother flow, coupled with higher temperature, can improve the drafting ability of the fireplace, thus making the fire burn cleaner and hotter. Protecting your chimney from water damage from all directions is a good investment.

Bookmark It

Hide Sites

If you have a wood burning fireplace inside your home, you can probably do some simple things to your fireplace and chimney to improve your home’s energy efficiency. Some of these are free and will give you an instant return on your time investment, while others can cost a bit of money. Even the things you can spend money on, though, will give you a much better return on your investment than you can get from a certificate of deposit at your local bank. The fact is that most wood burning fireplaces are energy hogs. When you have a fire burning in a standard fireplace, it is likely that your fireplace and chimney are sucking more cold air into your house than the heat from the fire is adding back to your house. Also, when you are not burning a fire, your chimney is probably acting like a long straw sucking warm air out and letting cold air back in.

To get some idea of how much your present fireplace and chimney system is costing you, pick a day when it is really cold outside and you aren’t burning a fire and hold your hand out in front of your fireplace or reach inside the firebox. Do you feel a cold draft falling out of the chimney? If you do, the obvious thing to check first is to make sure your damper is closed. If you still feel a draft with the damper closed, and you are likely to, it is because the metal damper parts have become warped and worn over the years and don’t seal well, anymore, so you have cold air freely falling down your chimney as if you had a gaping hole in your ceiling. A relatively inexpensive investment you can make is to install a Seal Tight Chimney Damper or Energy Top Chimney Damper on top of your chimney. These devices seal off the top of your flue when you are not using your fireplace and prevent heat loss through your chimney. They have a control rod that extends down to your fireplace so you can open and close the damper from inside instead of having to climb on your roof to remove any other kind of cover you may put on your chimney.

One of the best ways to address the problem of an inefficient fireplace is to install a wood burning insert inside your fireplace along with a flexible M-Flex stainless steel chimney liner. A modern wood burning insert is designed for high efficiency, so it actually releases far more heat back into your house than it sucks cold air in to feed the fire. The chimney liner also insulates your flue so you get better draft into your insert and more complete combustion of the fuel. An uninsulated flue lets smoke and combustion gases cool off by the time they reach the top of the chimney, which weakens your chimney’s draft, so insulating the flue helps keep the gases hot all the way out of your house.

You can improve your home’s energy efficiency with relatively inexpensive passive measures like installing a better damper, or you can make a fairly large investment in a wood burning insert to make your fireplace much more efficient. You will burn less wood and get more heat, so your savings in firewood costs will pay for the insert over time, probably at a rate much better than the less than one percent you can make on your money in a savings account.

Bookmark It

Hide Sites

Creosote buildup inside your chimney is the primary reason you will need to have the chimney cleaned, and it is the primary cause of chimney fires. Creosote is one of the chemical products of incomplete combustion of fuel. It is one of many compounds that is carried up your chimney through the flue to be vented safely to the outside air. Other products of combustion include smoke, carbon dioxide, carbon monoxide, and water, all of which also need to be vented from the building. When creosote is expelled from burning fuel, it enters the flue as a gas. As long as it remains in gaseous form, it does not build up inside the flue, but is safely vented outside. But, in most chimneys, the combustion gases cool enough by the time they reach the top of the flue that some of them condense into liquid form and adhere to the inside surface of the flue and on the surfaces of chimney caps and flame arrestors on top of the chimney. This is why creosote buildup is usually thicker the higher up the chimney you look.

There are several steps you can take to minimize creosote condensation inside your chimney. The easiest thing to do is to always burn well seasoned wood in your fireplace or woodstove. Green wood has a high water content than well seasoned wood, so it burns cooler and with more smoke, both of which contribute to creosote buildup in your chimney. You should also ensure that you get the most complete combustion of your wood that is possible for your given fireplace or woodstove. A small, hot fire burns the fuel more completely than a large, cooler fire. Under ideal combustion conditions, the only gases going up your chimney are carbon dioxide and water. If you try to stack your fire with too much fuel in order to make the fire burn longer, you will not have the hot fire that is necessary for good combustion. Closing off your woodstove damper to make the fire burn slower and longer has the same effect — a dirty fire with lots of creosote going up the flue. Once you have creosote going up the flue, the structure of your chimney can effect how well it is discharged to the air. If your chimney is built internal to the structure of your house, it will be better insulated than a chimney built on an outside wall. This will result in a hotter flue which will keep more of the creosote in a gaseous state on its way out, at least until it reaches the part of the chimney that is exposed to the winter chill above the roofline. By installing an insulated chimney liner, you can keep the flue hotter all the way to the top, minimizing creosote condensation.

So, the ideal setup for minimal chimney cleaning is burning well seasoned dry wood in a hot fire inside an efficient woodstove or fireplace, not restricting airflow by using dampers, and having an insulated flue inside your chimney, either by architectural design or by installation of an insulated chimney liner.

Bookmark It

Hide Sites

The Environmental Protection Agency (EPA) lists leaking chimneys among the primary sources of carbon monoxide inside homes and other buildings. Carbon monoxide is a clear and odorless gas that results from incomplete combustion of fuels. A leaking chimney can allow carbon monoxide, water vapor and other gases to enter the building structure surrounding the chimney. Carbon monoxide is heavier than air, so it will settle in low places in the house even if it originally leaks into the attic from high up the chimney. At low concentrations, carbon monoxide will cause flu-like symptoms in people who are exposed to it for a sufficient length of time. At higher concentrations, carbon monoxide can cause death without the victims being aware that they are in any danger. A well maintained chimney liner will keep the products of combustion from a fireplace, woodstove or furnace safely contained in the chimney as it flows up and out of the building.

A leaking chimney can also increase the risk of fire in the attached building. Cracks in the mortar, missing bricks, or broken clay liner tiles can allow intense heat and even flames to exit the flue into the chimney structure, possibly reaching flammable construction materials in the surrounding building. The result can be serious property damage or fatalities to the occupants of the building. A chimney liner will prevent dangerous heat transfer into the building structure, by physically blocking the escape of hot gases and flames and also by insulating the chimney to prevent overheating.

A properly insulated chimney liner also helps to prevent creosote buildup on the inside walls of the flue. Creosote is the primary fuel involved in chimney fires, which can cause serious damage to the chimney structure and spread to the attached building. Even if a chimney fire is contained within the chimney, it can cause serious damage to the inside of the flue and the structural integrity of the chimney. If you are aware that you have had a chimney fire, you should not use your fireplace or other appliance before you have your chimney inspected. A chimney liner helps to minimize creosote buildup by keeping the flue hot. By insulating the inside of the flue from the outside structure of the chimney, the chimney liner keeps the flue hotter than an un-lined flue. This minimizes condensation of creosote and moisture inside the flu, which is the cause of creosote buildup that can lead to a chimney fire.

You should have your chimney, chimney liner, flue, fireplace and other fuel burning appliances cleaned and inspected at least once a year. If the inspection finds any damage to the inside of the flue which compromises its sealing ability and resulting safety, you should have a new liner installed or other appropriate repairs made before you use the fuel burning appliance again.

Bookmark It

Hide Sites