Last Updated on October 6, 2026 by Umar Farooq
The best wet dry vacuum for gutters is one whose listing publishes an airflow in CFM and a suction figure in inches of water, and across 121 listings at the serious end of this category only 19 publish both — while 78 publish neither, 59 publish a peak horsepower that the motor manufacturer says is measured with the fan taken off the motor.
That last clause is not a figure of speech. It is a sentence from the technical manual of the company that builds the motors inside these machines, and once you have read it the number on the front of nearly every shop vacuum in the aisle stops being a specification.
This page audits two shelves: the machine, and the gutter kit that goes on the end of it and publishes less than the machine does. Which tool actually beats a wet leaf mat — scoop, tongs, jet or suction — is settled in the guide to the manual gutter cleaning tool and is not re-run here. What follows is the purchase.
Peak Horsepower Is Measured With the Fan Taken Off
Fifty-nine of the 121 listings lead with a peak horsepower figure. Here is how that figure is obtained, from the Lamb Electric universal vacuum motor technical manual published by Ametek’s Dynamic Fluid Solutions division — the firm whose motors sit in a large share of this category:
Peak Horsepower (PHP) has been used to rate canister vacuum cleaners for many years. To test for peak horsepower (PHP), fans are removed from the motor and the motor is energized. The peak inrush current for vacuum motors is typically in the range of 40-50 amps and lasts for only an instant. The PHP normally occurs during the inrush, at about 6,500 RPM, as the motor moves toward normal operating speeds in the range of 15,000-25,000 RPM.
So the number is taken with the fan off, during the inrush, at a speed the motor passes through on its way up. It is real, it is repeatable, and it describes a machine that is not assembled and is not moving air. Ametek then adds the part that matters: “Actual air performance of today’s high PHP motors may be lower than older units with lower PHP ratings.”
The shelf proves it twice over, from one brand, in one sentence each.
Shop-Vac’s 55-gallon drum head assembly publishes “3.0 peak horsepower, 109 CFM airflow, 105 inches of water in sealed pressure”. Shop-Vac’s 18-gallon utility vacuum publishes “6.0 peak horsepower, 130 CFM airflow, 50 in. sealed pressure (in. of water)”. Double the peak horsepower, less than half the sealed suction. Same manufacturer, same listing template, and the figure most buyers sort on runs backwards against the figure that describes the pull.
Five listings in the census publish a peak horsepower figure and an electrical input, which lets you check one against the other. Every one of the five claims more mechanical horsepower than the machine draws in electricity, and that is before anything is lost to heat, noise or the fan:
| What the listing publishes | Claimed, at 746 W per horsepower | Published input |
| 3.0 peak HP, 11 amps at 120 V | 2,238 W | 1,320 W |
| 6.0 peak HP, 11.8 amps at 120 V | 4,476 W | 1,416 W |
| 6 peak HP, 1,200 W motor | 4,476 W | 1,200 W |
| 6.0 peak HP, 2,400 W, two motors | 4,476 W | 2,400 W |
| 8.5 peak HP, 2,400 W, two motors | 6,341 W | 2,400 W |
The arithmetic is mine, the two numbers in each row come from the same bullet, and the worst row claims a shade under four times the machine’s whole electrical supply. Nobody is lying. The test produces that number, honestly, on a motor with no fan on it. It just has nothing to do with lifting a handful of wet maple leaves out of a trough at the top of a pole.
Only 6 of the 121 listings publish an amp draw at all and 15 publish a wattage, so for most of this aisle the headline figure cannot even be checked against the socket. Worth noting that the habit is not universal across power tools: this site’s audit of 51 air compressor listings found not one claiming a peak horsepower. The shop vacuum aisle kept it.
Sealed Suction and Airflow Sit at Opposite Ends of One Curve
The two figures worth having are the ones the aisle publishes least. Sealed suction — water lift, given in inches of water — is how hard the machine pulls. Airflow, in CFM, is how much air it moves. Lifting a wet clump of leaf up a tube is an airflow problem with a suction problem underneath it, and 78 of 121 listings publish neither.
Here is the part nobody puts on a box, and it comes from the same Ametek document. Sealed suction is measured with the inlet blocked, which means no air is moving. Maximum airflow is measured wide open, which means almost no vacuum is being developed. They sit at opposite ends of a single performance curve, and no machine ever operates at either end. Ametek is blunt about what that does to the figure most commonly advertised:
Sealed Vacuum is used extensively in rating and advertising central vacuum cleaners. This can be a misleading method of rating a cleaner as no work is being done by the unit while the inlet is sealed. Picking up dirt through a vacuum system requires both vacuum and airflow. When the vacuum is operating with the inlet sealed, there is no airflow and, hence, no dirt pick-up.
And then the warning that kills any attempt to rank machines by lift alone: “Some high sealed vacuum motors have less vacuum pressure at the normal operating points in cleaners than motors with lower sealed vacuum performance.”
The useful half of the same document is the operating point, which Ametek describes as an effective orifice — the whole system’s resistance collapsed into a single hole of equivalent diameter:
The maximum number of air watts generally occurs at an orifice point between 7/8″ and 5/8″. Most vacuum cleaners have been designed to operate at an effective orifice in this range to take advantage of the maximum efficiencies available from the vacuum motor. The effective orifice of a vacuum cleaning system is the total of the impedance to air flow that the system places on the motor. These would include the filtration system; hose length, construction and diameter; cleaner housing design and sealing; floor tools; etc.
For central systems the same document names a working figure of 16 mm, a hair under five-eighths of an inch.
Read that list again, because it is the whole argument of this page. Hose length and diameter are not a detail of the machine; they are part of the number. Bolt five feet of extra tube and a 120-degree bend onto a vacuum and you have moved its effective orifice, and therefore both figures, and the box was measured before any of it existed.
One conversion here does work, and since this site refuses most of them it is worth saying why. An inch of water column is 0.036127 psi, and a vacuum’s lift and a pump’s pressure are the same physical quantity — a static pressure difference measured with nothing flowing — so they compare honestly. The best sealed figure in the whole census, 105 inches, is 3.8 psi. A garden tap does about fifteen times that. Suction is not a strong force; it is a weak force applied to a large area of moving air, which is precisely why airflow is the half that lifts leaves. Both figures are also deadhead maxima that fall under working flow, which is the caveat Cat Pumps writes into its own plunger pump service manual: maximum specifications refer to individual attributes, and it is not implied that all maximums can be performed simultaneously. A pump maker had to print that. A vacuum maker never does.
Every Listing Gives You Gallons, Thirty-Eight Give You Airflow
I ran 57 search phrasings through the marketplace — tank sizes from 6 to 20 gallons, “shop vacuum 6.5 peak hp”, “high cfm shop vacuum”, “wet dry vacuum sealed suction”, plus a dozen brand names — and got 282 distinct products back. Stripping out the food vacuum sealers, the hard-floor mop machines, the upright dry vacuums, the bare hoses and the accessory kits leaves 121 self-contained wet/dry vacuums and jobsite dust extractors at the serious end of the category. I also re-ran every phrasing unfiltered and found no listing with a missing price, so nothing was quietly dropped from the count.
| What the listing publishes | Of 121 |
| A tank capacity in gallons | 105 |
| A peak horsepower figure | 59 |
| An airflow in CFM | 38 |
| A sealed suction figure in any unit | 28 |
| — of those, in inches of water | 20 |
| — of those, in kPa or mbar only | 8 |
| Both an airflow and a suction figure | 19 |
| Neither | 78 |
| Peak horsepower and gallons, and neither of the two | 46 |
Forty-six listings publish exactly the pair that tells you nothing: a horsepower taken with the fan off, and the volume of the bucket. That is not a handful of sellers each cutting a corner. Walk the brands and it is structural: DEWALT’s 19 listings publish a suction figure zero times. RIDGID’s 10 publish neither figure, not once. Craftsman’s 6, nothing. Kärcher’s 7, nothing. Shop-Vac’s 11 produce the two quoted above and nine more with a peak horsepower and a gallon count.
The firms that do publish are the jobsite dust-extractor makers — Nilfisk, Makita, Bosch, Fein, Dustless Technologies, Dapper Supply, IPC — which is a clue about who the disclosure is for. Those machines are sold to be bolted to a grinder under a silica rule, where somebody has to demonstrate capture. Nobody has to demonstrate anything about a gutter.
Two of the 38 airflow figures are not even suction figures. One Shop-Vac publishes 145 CFM as what the machine does “converted to a powerful 145 cfm air blower”; another publishes “100 CFM blower”. Both are correct and both describe the machine running the other way round, which is a different number on a different side of the same fan. If you are sorting a spreadsheet by CFM, two rows of it are backwards.
The Kit on the Shelf Is Five Feet of Full-Bore Tube
Now the accessory, and this is where the audit turned out differently from how I expected.
There are five gutter kits on the marketplace built for a wet/dry vacuum rather than a blower: one from Craftsman, one from WORKSHOP, three from Sealegend. Every one of them is 2-1/2 inch throughout — three say so emphatically, in the manner of a seller who has processed a lot of returns. “For 2-1/2 in. Vacuum Hoses only. NOT for use with hoses UNDER 2-1/2 inch. Confirm Your shop vac hose diameter first.”
So the thing I went looking for, twelve feet of stepped-down 1.25-inch tube, is not what the gutter aisle sells. The market solved the bore problem by refusing to narrow the bore, and then stopped. Three of the five kits publish a reach: 4.8 feet, 5 feet, 5.6 feet. The other two publish no length at all. None of the five publishes a single performance figure of any kind. Not an airflow, not a pressure drop, nothing. The deepest disclosure in this corner of the shelf is a count of extension wands.
Craftsman’s lists its contents — “Gutter Nozzle, Blower Nozzle and 2 Extension Wands” — and nine compatible vacuum model numbers, which is useful and is not a measurement; its carton is 23.5 inches on the longest side, so two wands is a bit over three feet, which is the figure the listing declines to give. WORKSHOP’s goes further and makes a joke of it: “Additional extension wands allow for extended reach because after all what is a wet dry vacuum gutter cleaning kit if you can’t reach your gutters.” It then publishes no reach.
What all of them do say, in one form or another, is that the bore is the point. WORKSHOP: “2-1/2-inch diameter vacuum attachments allows for larger sized debris collection and maximum airflow.” Sealegend: taking the tip nozzle off “provide larger volume for leaf blowing/vacuuming with max airflow.” And a wand sold on its own by Vacmaster puts the mechanism in one line the machine listings never manage: “Full 2.5″ bore maintains maximum suction and passes large chips with ease.” Three sellers of the simplest parts in this chain name airflow as the thing their product protects. Not one publishes any.
Where the long narrow tube genuinely exists is on the machine side, and that is what answers the question properly. Three of the dust extractors here ship a 1-1/4 inch hose, two of them over thirteen feet long — and those are precisely the machines that publish an airflow and a water lift, measured at the inlet rather than at the far end of thirteen feet of narrow corrugated tube. Ametek says what the right test would be: “The final test of a cleaner would be to determine air watts at the end of the hose as this will measure the amount of effective work being done by the system.” Across 121 machine listings and 5 gutter kits, the count of figures measured there is zero.
One more thing the kits cannot do, which no listing mentions: a 2-1/2 inch tube does not get under a cover. If your trough is hidden, the debris is on top of the guard rather than in the gutter, and whether that panel can safely be lifted at all is a roof question before it is a vacuum question.
Air Watts Is the Figure ASTM Named and Vacmaster Printed Twice
There is a standard figure for exactly this, and it has been around for decades. ASTM F558, *Standard Test Method for Measuring Air Performance Characteristics of Vacuum Cleaners*, covers the “determination of suction, air flow, air power, maximum air power, and input power under standard conditions”. The document itself sits behind a paywall and I have not read it, so I am quoting the published scope and no figure out of it. The arithmetic is not a secret, though, and Ametek prints the simplified version: air watts are the vacuum in inches of water multiplied by the airflow in CFM and divided by 8.5. Ametek calls it “a logical method of rating vacuum cleaners, as it measures the work being done by the machine”, and then concedes, with feeling, that “this term is not well understood and many manufacturers do not use it.”
Four of 121 listings mention air watts. Two of the four publish a value, both from Vacmaster, both in the same Beast range, and the two values are these:
- the 16-gallon: “Beast Series High-Performance Motor with 360 Air Watts of Power”
- the 12-gallon: “Beast Series High Performance Motor with 36 Air Watts of Power”
A factor of ten between two siblings whose other five bullets are identical word for word. One of those two numbers has lost a digit, and a reader has no way to know which. The only brand in this entire category publishing the figure the standard recommends publishes it twice and gets it wrong once.
It gets worse in an instructive way. That same 16-gallon machine has a second listing under a different suffix, publishing “Powerful Airflow at 145 CFM” and no air watts at all. One machine, two listings, two figures, no overlap, no water lift on either.
Which brings me to the one conversion on this page I am refusing. I have both numbers for 19 listings, multiplying them would produce an air-watt figure for each, it would reorder the shelf in a satisfying way, and it would be wrong. Ametek is explicit that the vacuum is recorded “at a number of orifice points” and that peak air watts occur at an orifice between 5/8 and 7/8 of an inch. A sealed-inlet reading and a wide-open reading are taken at the two orifices where air watts are zero by definition, and you cannot multiply two extremes of a curve to get a point on it. The figure the standard asks for cannot be assembled from the figures the box gives you, which is worth more than any ranking I could have published.
Two of Three Wet Vac Recalls Are About the Blower Port
A detour through the regulator before any buying advice, because this is a safety finding I did not go looking for. Search the Consumer Product Safety Commission’s recall database for wet/dry vacuums and three notices come back, all from one manufacturer, and two of the three are about the blower port — the exact port every one of these gutter kits ships a nozzle for.
In December 2003 the Commission and Emerson Tool Company recalled Craftsman 16-gallon and RIDGID 12- and 16-gallon wet/dry vacuums because “the exhaust blower ports on the wet/dry vacuums are large enough for a small child to reach inside and touch the spinning blower wheel.” Emerson had received 10 reports of children inserting their arms into the ports and receiving minor cuts and abrasions to their fingertips. In January 2005 the same firm recalled about 6,500 RIDGID 16-gallon 2-in-1 Blower Vacs, model WD16650, because “the air intake shield may be missing. Consumers can suffer lacerations if they come into contact with the intake blower wheel” — two reported fingertip lacerations. The third, from September 2018, covers about 208,000 RIDGID NXT vacuums, models HD06000 and HD09000, whose on/off switch “can become dislodged and expose energized wiring”.
All three are old, all three were remedied, and none of those model numbers appears anywhere in this census. I ran the regulator’s database against every brand before linking anything: Shop-Vac, Dustless Technologies, Dapper Supply, Nilfisk, Vacmaster and Fein return no notices at all, and Bosch returns twenty-two of which none is a vacuum.
The reason the old notices still matter is the geometry, which has not changed. A wet/dry vacuum’s blower port is an opening a few inches from a wheel spinning at fifteen to twenty-five thousand rpm, and the gutter kit’s instructions are to put your hand on it and fit a tube — Craftsman’s own kit says “attach your shop vacuum hose to the blowing port and connect this tool to the hose to blow leaves out of your gutters effortlessly.” Do that with the machine running and you are reaching into the one part of the appliance with a documented history of taking fingertips off children. Fit the tube unplugged, every time, and keep anyone small on the other side of the garden. Blowing also relocates debris rather than removing it, which is a lateral move with better optics, and where the fine silt ends up afterwards is already set out on the gutter and drain cleaning page.
Three Machines That Printed Airflow Next to Suction
Nineteen listings publish both figures. These three are the ones I would plug in, chosen on disclosure first and airflow second, because airflow carries a leaf up a tube and suction only gets it moving. Each is reviewed with its limitation, and every brand went through the recall database first.
Dustless Technologies HEPA Wet+Dry Pro, 8 gallon, D1618. The pick, and it wins on a bullet that has nothing to do with air. Its listing publishes “138-CFM/83″ Water Lift motor” — both figures, in the units the aisle uses — and then this: “Hydrophobic polyester filter allows dry to wet pickup without changing filters.” That sentence is the reason this machine suits a gutter better than anything else in the census. A trough is two materials stacked: dry leaf on top, wet silt and grit underneath, and the state changes halfway down. RIDGID’s own owner’s manual for its 14-gallon professional vacuum states the problem plainly — “A dry filter is necessary to pick up dry material. If you use your Vac to pick up dust when the filter is wet, the filter will clog quickly and be very difficult to clean” — and tells you to remove the filter entirely for large amounts of liquid. A filter cannot be dry and wet at once, and a gutter asks it to be. One filter that does not care is worth more here than twenty inches of extra lift. The limitation is that those two figures are the entire air-performance disclosure on the page — no voltage, no amps, no hose bore, no hose length, and nothing about what the semi-automatic filter cleaning recovers. Eight gallons is also modest for a forty-foot run with silt in it, and that filter mechanism needs a hand on it rather than running itself.
Dapper Supply 8-gallon wet/dry dust extractor with auto HEPA filter. Here because it publishes more about itself than any other listing in the census, and most of what it publishes is the thing this page says is missing. One bullet gives “140 CFM airflow, 20 kPa vacuum, and 84.3 in. static water lift” — the suction figure twice, in two unit systems, which agree to within about five per cent when you convert them. Another gives the hose: “13.1 ft hose with 1-1/4″ diameter.” That is the only listing anywhere in 121 that tells you the bore and the length of the tube its own figures were *not* measured through. A third gives the filter-cleaning interval: every 25 seconds. The limitation is that Dapper publishes a great deal and does not publish it consistently. A second Dapper 8-gallon listing gives the same 140 CFM against 72.3 inches of static water lift — a twelve-inch spread between two listings of near-identical machines — and the 10-gallon in the same family prints “23 kPa suction, 151 CFM airflow, and up to 98 PSI” in one sentence, where the two suction figures differ by a factor of about thirty. Buy the one with the number you checked, and check it.
Shop-Vac 9601806, 18 gallon utility vacuum. This is the only listing in the whole census that uses the standard’s own vocabulary with the units spelled out for the reader: “6.0 peak horsepower, 130 CFM airflow, 50 in. sealed pressure (in. of water), 120V~60Hz 11.8 Amps”. Sealed pressure, in inches of water, named as such, beside the amps that let you check the rest. It also has the largest tank of the three, a 2-1/2 inch hose that matches every gutter kit on the market without an adapter, and an onboard pump that empties it through a garden hose rather than asking you to tip eighteen gallons of leaf soup down the drive. The limitation is that the honest disclosure reveals an unimpressive number. Fifty inches is the lowest sealed pressure published by anything in this census that publishes one — two-thirds down on the best figure here — and the 6.0 peak horsepower in the same bullet is 3.16 times the machine’s own published electrical input, which is the clearest illustration on this page of why that figure should be ignored. Buy it for the airflow, the bore and the pump, and read the suction figure as a ceiling, not a promise.
And the kit on the end gets no link from me, deliberately. Every gutter kit for a wet/dry vacuum sits below this site’s affiliate threshold, so recommending one earns nothing and I would rather name it than steer you to a dearer bundle to make a link work. Get the 2-1/2 inch kit with the most extension wands that fits your hose — Sealegend’s four-wand version and Craftsman’s two-wand version are the same product at different lengths — and take the full-bore one over anything that steps down, for the reason Vacmaster’s wand copy gives. Confirm your hose diameter first; three of the five kits lead with a warning about that, which tells you how often it goes wrong.
Ninety-Eight of What?
Everything below I read in full and left without a button, and the first four failed in the same specific way: the number was there and the unit was wrong, missing, contradicted, or doing a job units do not do.
Fein’s Turbo II X publishes “98 PSI static water lift”. Those four words cannot all be true together. Static water lift is measured in inches of water; 98 psi of vacuum would be roughly 2,700 inches of water column, which is about six and a half atmospheres of suction below atmospheric pressure, and there is only one atmosphere available to remove. Read it as 98 inches and it becomes an excellent figure — 3.5 psi, right at the top of this census. Which is almost certainly what it is, and I am not linking a machine whose headline specification requires the reader to correct the unit.
Fein’s Turbo I, the smaller sibling, publishes “151 CFM and 98 of water lift”. Ninety-eight of nothing at all. Same number, same brand, one listing with the wrong unit and one with no unit, and a buyer comparing the two learns only that Fein has a 98 somewhere.
Dapper Supply’s 10-gallon publishes “23 kPa suction, 151 CFM airflow, and up to 98 PSI”. Twenty-three kilopascals is about 92 inches of water, or 3.3 psi. The same sentence then offers 98 psi. One of those is the machine and the other is thirty times the machine, and they are eleven words apart. Two sellers of similar 1,100 to 1,200 watt extractors have independently printed a 98 next to a 151 CFM, which I record without drawing a conclusion from it: their feature copy shares nothing else.
The cordless end offers a suction figure as a mode selector. Three battery shop vacuums publish “dual suction modes: 9kPa for routine cleaning and 15kPa for pet hair and stubborn dirt” — 36 and 60 inches of water, real information presented as a dial setting, with no airflow figure anywhere beside it. For a gutter, airflow was the half you needed.
Nilfisk’s three Aero listings fail differently, and more honestly. Each publishes “Airflow: 127 CFM / Waterlift: 84 Inches” — a clean pair, in the right units, properly labelled, and *identical* across 5, 7 and 8-gallon machines. That is a motor specification wearing three tank sizes: candid about the component, silent about the product, and no use at all for choosing between the three. The strongest figures in the census belong to Bosch’s 14-gallon extractor, which publishes 150 CFM alongside “a sustainable maximum 97 in. static water lift” — and that adjective is the most honest word on any listing here, since it concedes a figure can be true at the start of a job and not later. It goes unlinked only because fourteen gallons of jobsite dust extractor on casters is not what anyone carries round a house twice a year.
And then the forty-six. The largest group here publishes a peak horsepower and a number of gallons and nothing else: DEWALT across nineteen listings with no suction figure anywhere, RIDGID across ten with neither, Craftsman across six, Kärcher across seven. RIDGID’s position is the most complete, because its own forty-page owner’s manual for a professional 14-gallon machine publishes no air-performance figure either, and describes its extension wands like this: “These wands can be connected together and provides additional length for more reach.” Reach, and nothing else — which is, word for substance, what the gutter kits say too. The whole chain from motor to nozzle is sold on length.
Worth knowing what the trade does with the same two numbers, because it publishes both every time, with the pole length beside them. One industrial gutter vacuum publishes “Motor wattage: 3300W”, “LPM Airflow: 12,000 LPM (240v) / 10,000 LPM (110v)” and “Water lift: 145″ (240v) / 95″ (110v)” — the same machine losing a third of its pull on a 110-volt supply, disclosed. Another publishes 379.6 CFM, 94.56 inches of water lift, three 1,200-watt motors, a “2.8-in ID Cyclonic Side Inlet” and a generator requirement of “minimum of 5,500 starting watts and 5,000 running watts” into a four-prong twist-lock. I am naming them in prose and linking neither. The point is not that you should buy one; it is that the class built for this exact job discloses both figures as a matter of course, runs on a supply no gutter has anywhere near it, and is three motors wide.
FAQ
What is the best wet dry vacuum for gutters?
One whose listing publishes an airflow in CFM and a suction figure in inches of water, because those two describe the only thing that matters — whether moving air can carry debris up a tube — and 78 of the 121 listings I audited publish neither. On that test the strongest candidate is the Dustless Technologies 8-gallon, which publishes 138 CFM and 83 inches of lift and also carries a filter rated for dry and wet pickup without a change, which is the specific thing a gutter asks of a vacuum.
Is water lift or airflow more important for a gutter vacuum?
Airflow. Lift gets a clump moving; velocity in the tube is what carries it twelve feet to the tank, and velocity comes from flow. The motor manufacturer’s technical manual says the same thing from the other direction — picking up debris “requires both vacuum and airflow”, and a sealed reading describes a machine doing no work at all. If a listing gives you only one of the two, the airflow figure is the more useful one for this job.
How much reach does a shop vac gutter kit actually give you?
Between three and six feet, and two of the five will not tell you. The three that do publish 4.8, 5 and 5.6 feet. Add that to a raised arm and a single-storey gutter is reachable from the ground on a good day. A second storey is not, and no amount of extra tube fixes it, because the tube is also where the airflow goes.
Does a gutter cleaning kit fit any wet dry vacuum?
Only if your hose is 2-1/2 inch. Every kit built for a wet/dry vacuum is full 2-1/2 inch bore, and three of the five carry a capitalised warning against using anything narrower. If your machine has a 1-7/8 or 1-1/4 inch hose — most compact and cordless models do — it does not fit, and adapting down works against the one property the kit exists to preserve.
Will a wet dry vacuum pick up wet leaves out of a gutter?
Not well, and the reason is the mat rather than the machine. Soaked leaf packs into a single cohesive sheet that will not break into pieces small enough to enter a tube, and the first piece that half enters seals it. That mechanism, and which tools do beat a wet mat, is worked out in full on this site’s manual gutter tool page. A vacuum is a dry-week tool: autumn leaf before the rain, and pine needles, which it handles better than anything else in the aisle.
Why does my shop vac lose suction once the extension wands are on?
Because every foot of tube, every bend and the filter all add to what the motor is pulling against, and the figures on the box were measured before any of them existed. The motor maker calls the total an “effective orifice” and lists hose length, construction and diameter among the things that set it. Machines are designed to work best at an effective orifice between five-eighths and seven-eighths of an inch, so a long accessory train moves the machine off its best point. A wider bore and fewer joints both help, and nobody publishes how much.
Dry Leaf, Wide Bore, and a Short Pole
Two figures decide this purchase and the aisle mostly declines to print either, so the rule is short: buy the machine on its published airflow, buy the kit on its bore, do the job in a dry week. The vacuum is a garage purchase that happens to clean gutters a few afternoons a year, which is the right way round — nothing here is worth owning for the gutters alone, and the silt under the leaves comes out with water rather than air once the bulk is gone.
What the audit changed in my own head is the middle of the chain. I expected the suction to die in twelve feet of narrow tube, and the shelf does not sell twelve feet of narrow tube — it sells five feet of wide tube with no number on it, bolted to a machine whose numbers stop at the inlet, through a hose whose length and diameter the motor manufacturer names as part of the measurement. Everything between the motor and the gutter is unmeasured, and the firm that builds the motors already wrote down which figure would settle it: the air watts at the end of the hose. Out of 121 machines and five kits, the count of anyone publishing that is nought.
So when the trough is dry and the needles are down, hook the wand over the lip and enjoy it, because that is the week this tool is genuinely lovely. When the gutter is a grey sheet that holds its shape when you poke it, put the vacuum back in the garage and fetch something with a squared edge on it. And once a year, whatever you clear it with, go and look at the hangers and the drip edge while you are up there, because a spotless trough on a gutter that is coming off the fascia is a very tidy way to lose a fascia.
