A chimney flue is a vertical, soot-blackened, sometimes wet pipe that you cannot see into from either end. A borescope is the only affordable way to put your eye inside it. The catch is that most endoscopes sold for this job were designed for drains, engines or walls, and the specification that matters for a flue is not the one the listing shouts about.
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This comparison was built from the manufacturer listings supplied for each product. Every specification quoted, including probe diameter, cable length, resolution, IP rating and lighting, is taken directly from those listings. Where a listing does not publish a figure, the table and the review say so rather than estimating.
A slim probe, a long cable and a side-view camera that lets you look at the flue wall, not just down it.
A long, cheap, self-contained endoscope that will confirm a blockage or a nest, but not much more.
A steerable tip and a very slim probe, but a short cable that limits it to the top of the flue.
A 5ft articulating gooseneck that holds its shape, useful for the top of a flue or a stove outlet.
A 16.4ft semi-rigid probe that plugs into your phone, for buyers who already carry a screen.
A self-contained 16.4ft scope with a side camera, for buyers who want dual-lens without the premium.
No pick matches that combination yet. Try a wider budget or a different measurement.
| Pick | Probe diameter | Cable length | Lighting | Waterproofing | Screen | Side view | |
|---|---|---|---|---|---|---|---|
| 5.5mm | 16.5ft | Not stated | Not stated | 5 inch, 1080P | Yes, 90 degree | View | |
| 7.9mm | 16.5ft | 8 adjustable LEDs | IP67 | 4.3 inch, 1920x1080P | No | View | |
| 0.22in (approx 5.6mm) | 4ft | Adjustable LEDs | Not stated | 4.3 inch, 1920x1080P | No, articulating | View | |
| Not stated | 5ft | Not stated | Not stated | 4.5 inch IPS | No, articulating | View | |
| 7.9mm | 16.4ft | 8 adjustable LEDs | IP67 | Phone screen | No | View | |
| Not stated | 16.4ft | 8 adjustable LEDs | IP67 | 5 inch, 1080P | Yes | View |
Cells show only what the manufacturer listing publishes. Where a figure is absent the cell reads Not stated. Cable lengths are as stated and are not a guarantee of usable reach inside a flue with offsets.
The flue decides the tool. Work back from the flue, not forward from the feature list.
A nominal 6 inch flue with an offset may not pass a 7.9mm probe comfortably. If the listing does not publish a probe diameter, you cannot know, so prefer models that state it.
A forward-facing camera answers is it clear. A side-view or articulating camera answers is the wall damaged. Creosote glaze and liner cracks need the second kind.
A 4ft or 5ft cable inspects the top of a flue or a stove outlet. A 16ft cable reaches most domestic flues from the terminal. Tall or commercial stacks need more.
On a roof you want one hand on the cable and one on the screen. A phone-based scope is lighter but leaves you juggling a phone in bad weather.
Flues are damp and sometimes hot. IP67 is a useful minimum. A published temperature rating is rarer, and its absence is a real limitation, not a detail.
A camera documents condition; it does not certify it. Keep photos for your own records and for any conversation with a sweep or an installer.
No. A borescope shows you the inside of the flue, which is useful evidence, but it cannot certify a flue as safe. It cannot measure clearance to combustibles, it cannot test the integrity of a liner under pressure, and it cannot see behind a register plate or through a soot layer. A camera is a documentation tool. A qualified sweep or installer makes the safety judgement.
Smaller is easier. A 5.5mm probe passes narrow flues and offsets that a 7.9mm probe may not. If the listing does not publish a probe diameter, you cannot predict whether it will pass your flue, so prefer a model that states the figure.
Measure the flue run and add a margin for offsets. A 16ft cable reaches most domestic flues from the terminal. A 4ft or 5ft cable is enough for the top section, a stove outlet or a register plate, but not a full two-storey run.
Only if the probe is rated for it. IP67 is the common rating in this class and means the probe can be immersed briefly. Some listings publish no IP rating at all, and those should be treated as dry-flue tools. Damp flues are common, so this is worth checking before you buy.
You can, but the geometry is wrong. Drain cameras are built to look forward down a pipe for blockages. A chimney inspection is mostly about the condition of the wall, which needs a side-view or articulating camera. A drain camera will confirm a clear flue and not much else.
Only if you have offsets or bends that a semi-rigid cable cannot navigate. Articulation lets you steer the tip, which is genuinely useful in a flue with a dogleg. The trade-off is that articulating mechanisms are more delicate, and the models here with articulation have shorter cables.
The reason this is the pick for flue work is the combination of a 5.5mm probe and a 90 degree side camera. A flue is not a drain; you are not looking for a blockage at the bottom, you are looking at the condition of the wall along its length. Creosote glaze, spalled flue tile, a cracked liner and a failed mortar joint all sit on the wall, parallel to the camera axis. A forward-facing camera looking down a black pipe shows you a bright spot and a lot of nothing. The side camera on P7 lets you press the probe against one wall and look across at the opposite wall, which is how you actually see damage.
The 5.5mm probe matters because flues are often smaller than people assume. A nominal 6 inch flue with an offset, or a lined flue with a slightly reduced cross-section, will pass a 5.5mm probe far more easily than a 7.9mm one, and the smaller head is less likely to snag on a rough mortar joint on the way back up. The 16.5ft length is enough for a typical single-storey to two-storey flue run from the top, though it will not reach the full length of a tall industrial stack.
The listing does not publish an IP rating for this model, so treat it as a dry-flue tool. Chimneys are often damp, and a wet flue with a non-waterproof probe is a risk. The 5 inch screen is self-contained, which is an advantage on a roof where you do not want to be holding a phone in the rain.
If your question is simply whether the flue is clear, this does the job. The 16.5ft cable reaches up most domestic flues from the top, the 7.9mm probe passes a swept 6 inch flue without trouble, and the eight LEDs are enough to light a soot-black pipe at close range. The short 1.29in lens body is a genuine advantage in a flue because it turns corners in a tight offset more readily than a long camera head.
What it will not do is show you the flue wall properly. The camera faces forward, so you see down the pipe. You can sometimes angle the semi-rigid cable to press the lens against one side and get an oblique view of the opposite wall, but that is a workaround, not a design feature. For confirming a bird nest, a fallen brick or a heavy soot fall, it is fine. For assessing creosote glaze or a hairline crack in a liner, it is the wrong tool.
The IP67 rating is worth noting because flues are frequently damp and a wet probe is a real possibility. The listing does not publish a temperature rating, so do not push it into a hot flue immediately after a fire.
Articulation is the feature that separates a frustrating flue inspection from a straightforward one. When the probe reaches an offset or a bend, a fixed camera either goes round it or it does not. A two-way articulating tip lets you steer the head left and right, which means you can look at the flue wall from an angle rather than only straight ahead. The 210 degree range is generous, and the 0.22in probe is slim enough for almost any flue you will meet.
The overheat alarm is a genuinely useful feature for chimney work. The listing states that a temperature sensor displays a red icon alert in high-temperature environments such as automotive exhausts. A flue that has recently had a fire in it is exactly that kind of environment, and a warning before the camera cooks is worth having. Note that this is an alarm, not a rating; the listing does not publish a maximum operating temperature.
The limitation is the 4ft cable. That is enough to inspect the top section of a flue from the terminal, and enough to look at a register plate or a stove outlet from below, but it will not run the length of a two-storey chimney. If your work is mostly short reaches and awkward bends, this is the smart pick. If you need to see the whole flue, you need a longer cable.
This is a shorter, stiffer cousin of the Anykit. The 5ft semi-rigid gooseneck is designed to hold the shape you bend it into, which is useful when you want to hook the camera around a bend and keep it there while you look at the screen. In a flue, that means you can push it down from the terminal, bend it to one side and inspect the wall at that depth without holding the cable in a precise position.
The articulating tip adds the ability to steer once the probe is inside, which matters at an offset. The 4.5 inch screen is self-contained and bright enough for outdoor use. The listing does not publish a probe diameter, an IP rating or a temperature rating, which are the three specifications a chimney technician would want to know. Without a published diameter, you cannot be certain it will pass a narrow flue.
Treat this as a tool for the first few feet of a flue, a stove outlet, a register plate or a wall cavity that connects to a chimney. It is not a full-flue inspection camera. The 5ft cable is the hard limit.
The appeal here is that you supply the screen. If you already carry a phone with a good display, a plug-in endoscope is lighter and cheaper than a self-contained unit, and the phone screen is usually brighter and higher resolution than a small built-in panel. The 16.4ft semi-rigid cable is the same class as the MugEasy, and the 7.9mm probe and eight LEDs are the standard configuration for this price band.
For chimney work, the same limitation applies as to any forward-facing 7.9mm endoscope: it confirms a clear or blocked flue, it does not inspect the wall well. The IP67 rating is useful in a damp flue. The listing states plug-and-play with no pairing, which matters on a roof where you want the tool to work first time.
The practical drawback of a phone-based scope in a chimney context is that you are holding a phone in one hand and feeding cable with the other, often on a roof or at a stove. A self-contained unit with a built-in screen is easier to manage in that position. If you mostly inspect from a safe indoor access point, the phone option is fine.
The dual-lens arrangement is the important part. A side camera lets you look at the flue wall rather than down the pipe, which is what you need for creosote, cracks and liner damage. This model gives you that at a lower position in the range than the Teslong P7, with a 16.4ft cable and a self-contained 5 inch screen.
The trade-off is resolution and probe diameter. The listing states 1080P, not 1920P, and it does not publish a probe diameter. Without a stated diameter you cannot be sure it will pass a narrow flue, and the 1.2 to 4 inch focus range means the camera is optimised for close work, which is actually appropriate inside a flue where the wall is only a few inches away. The IP67 rating is a plus in a damp chimney.
If you want a side-view camera and a long cable but do not want to pay for the slimmest probe, this is a reasonable compromise. If probe diameter is critical to your flue, choose a model that publishes it.
Short answer: For most chimney work the practical pick is P7, the Teslong 5.5mm dual-lens borescope, because its 5.5mm probe and 16.5ft cable let you pass a swept or lined flue and its side-view camera lets you look at the flue wall rather than straight down the pipe. P2, the MugEasy 16.5ft endoscope, is the value option if you only need to confirm a blockage or a bird nest and can accept a 7.9mm probe. P10, the Anykit articulating borescope, is the smart pick for tight offsets and bends because the tip steers, but its 4ft cable is short for a full flue run. None of these cameras certifies a flue as safe; they document what you can see.
A chimney flue is a vertical pipe, often square or rectangular in section, lined with clay tiles, a stainless liner or, in older properties, bare brick. It is coated in soot, frequently damp, and sometimes glazed with creosote. The inside is not uniform: mortar joints protrude, tiles are misaligned, and offsets step the flue sideways. This matters because the camera you choose has to cope with all of it.
The first thing most people discover is that a forward-facing camera looking down a flue shows very little. You see a bright spot on the far wall and a lot of black. The reason is geometry: the camera looks along the axis of the pipe, but the damage you care about, cracked tiles, spalled brick, creosote glaze, sits on the wall, parallel to that axis. To see it you need either a side-view camera or an articulating tip that can be turned to look across the flue. This is the single most important distinction in the category, and it is the one most listings bury.
The second thing is that flues are smaller than people expect. A nominal 6 inch flue with an offset may not pass a 7.9mm probe comfortably, especially on the way back up when the cable has to follow the same path in reverse. A 5.5mm probe is a meaningful advantage here. If a listing does not publish a probe diameter, you cannot predict whether it will pass your flue, and that uncertainty is worth avoiding.
Soot is a broadband absorber. It reflects almost no light, which is why a flue looks like a black hole even with a bright LED on the camera. The practical consequence is that you need the light close to the surface you are inspecting. A camera with eight adjustable LEDs a few inches from the wall will show you the texture of the soot and any glaze on it. The same camera at the far side of a 9 inch flue will show you a dim grey smear.
Creosote is the specific hazard. It forms when wood is burned slowly or with insufficient air, and it deposits on the flue wall as a tar-like layer that can be glossy, flaky or hard. Glazed creosote is the dangerous form because it is dense and ignites at a lower temperature than soot. A borescope can show you that the glaze is there and roughly how thick it looks, which is useful information for a sweep. It cannot measure the thickness, and it cannot tell you the ignition temperature of what it sees. Treat the image as an indication, not a measurement.
Lighting also interacts with the camera’s focus range. Many of these probes are optimised for close work, a few inches from the lens. Inside a flue that is usually what you want, because the wall is close. But it means that a distant view down a long flue will be soft. If you need to see something at the far end of a 30ft run, no camera in this class will show it clearly.
Cable length is the specification buyers focus on, and it is the one most often misunderstood. A 16ft cable does not mean you can inspect a 16ft flue. Offsets, bends and rough mortar joints all consume length, and the cable has to make the return journey through the same obstructions. A realistic working reach is shorter than the stated figure, sometimes by several feet.
Stiffness matters as much as length. Semi-rigid cables hold their shape, which lets you push them up a flue and steer them slightly by rotating the cable. That is enough for a straight flue. It is not enough for a sharp offset, where the cable will simply stop or kink. An articulating probe solves this by letting you steer the tip, but articulation mechanisms are more delicate and the models here with articulation have shorter cables, typically 4ft to 5ft.
The practical advice is to measure your flue run, add a margin for offsets, and choose the longest cable you can get in the probe diameter you need. If those two requirements conflict, the probe diameter usually wins, because a camera that will not pass the flue is useless regardless of how much cable it has.
A borescope is an evidence tool, not a certification tool. It shows you what is visible from the position of the lens. It does not show you what is behind a soot layer, behind a register plate, or inside a void that the flue passes through. It does not measure clearance to combustible materials, which is a building regulation matter and one of the most common causes of chimney fires. It does not test a liner for gas tightness. It does not tell you whether the flue is the correct size for the appliance.
This matters because the images a borescope produces are compelling. It is easy to look at a clear flue on a screen and conclude the chimney is fine. The correct conclusion is narrower: the parts of the flue that the camera could see, at the time of inspection, looked like this. A qualified sweep or installer makes the safety judgement, and in many jurisdictions a chimney inspection for insurance or building control purposes requires a person, not a camera.
Where a borescope is genuinely valuable is in documentation. Photographs of a flue before and after a sweep, of a liner installation, or of a suspected crack give you a record. They help you have a specific conversation with a professional. They are not a substitute for one. If your concern is the air quality in the room the appliance serves, a air quality monitor answers a different question, and if your concern is the building envelope around the flue, a thermal camera for building envelope inspections shows heat loss that a borescope cannot. For the flue interior itself, the camera is the right tool, provided you understand its limits.
If you are choosing between a borescope and a dedicated drain camera, the plumbing and drain borescopes page explains where the two categories diverge. And if you need to inspect an engine or a wall cavity as well as a flue, the general borescope roundup covers the wider field.
This comparison was built from the manufacturer listings supplied for each product. Every specification quoted, including probe diameter, cable length, resolution, IP rating and lighting, is taken directly from those listings. Where a listing does not publish a figure, the table and the review say so rather than estimating. Products that did not belong to the chimney and flue topic, such as long-cable sewer reels and USB scopes intended for automotive diagnostics, were excluded. No laboratory testing was performed and no measurements of our own are published.
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