The quietest stackable washer and dryer we can verify is Bosch's 500 Series pair. Bosch rates the WGB24600UC washer at 51 dBA for washing and 75 dBA for spinning, and the WQB245B0UC heat pump dryer that stacks on it lists 62 dBA on its spec sheet and 63 dBA on its product page. Bosch ties none of the three to a program, a test distance or a standard, and no maker gives a figure for the two machines once they are stacked: every number on this page belongs to one machine standing on its own feet.
Bosch is the only maker that prints a wash, a spin and a dryer figure for more than one stacking pair, so its three pairs are the only ones we can rank against each other. Its 300 Series washer spins quieter, at 72 dBA, under a 67 dBA condensation dryer. Beko prints the same three kinds of figure for one pair whose washer runs on 120 V, and ASKO prints 61 dB(A) for drying on dryers whose washers carry no figure at all. The second half of this page is what stacking itself changes: the kit, the floor, the leveling, and a dryer running on top of a spinning washer.
Our picks are listed above, with full specifications for each.
Bosch prints all three for each of its compact pairs. The washers carry "Noise level washing" and "Noise level spinning" on their product pages and "Silence level" for washing and spinning on spec sheets dated 9/26; the dryers carry "Silence level". The 300 Series WGA14400UC lists 52 and 72 dBA, while the 500 Series WGB24600UC and the 800 Series WGB246AXUC share 51 and 75. The 300 Series WPA12100UC condensation dryer lists 67 dBA on its sheet and its page.
The two heat pump dryers are where Bosch disagrees with itself. Their spec sheets, for the WQB245B0UC (500 Series) and the WQB245AXUC (800 Series), are both dated 9/26 and both print "Silence level 62 dBA". Their product pages listed "Silence Level" 63 dBA when we read them on 10 and 13 October. We rank on 63, the less flattering figure; the order of Bosch's three pairs comes out the same either way.
Beko prints the same labels for one pair. The specification sheet for the WFTV10733XC washer, published by Beko U.S., Inc. in April 2023, gives "Silence Level" figures of 52 dBA for washing and 76 dBA for spinning, although Beko's product page for the washer leaves noise out entirely. The HPD24414W2 heat pump dryer lists 66 dBA on both its page and its sheet, and the sheet names the WFTV10733XC as its matching washer.
ASKO gives its current heat pump dryers, the T3HW, T5HXLW and T7HXLW, the same line, "Noise level drying dB(A): 61", and gives nothing for the washers they stand on: the W3W, W5XLW and W7XLW product sheets have no noise row. Its older T411HS.W, now marked "Limited availability" on ASKO's site, lists 65.
Blomberg could not be counted. Its page for the WM98220SX washer carries a spec table labelled WM98200SX2, a 2.5 cu ft model, with 52 and 76 dBA, and its page for the DHP24404W3 dryer carries a table labelled DHP24400W, with 65 dBA. Neither table describes the machine on sale. Equator prints "Quiet 60 dB" for one wash program on the washer in its EW 822 sets, with no weighting and nothing for the dryer.
Nobody else we read prints a figure for a stacking pair: not Miele for the 120 V WXC280 and TXB360WP, not Electrolux for the full-size ELFW7637AT, and not Midea for its compact MLHW27S7BCG or its full-size MLH45N1AWW, both of which Midea lists as stackable.
All six Bosch machines share one set of labels, so the three pairs can be compared one figure at a time, and they do not agree on a winner.
- Washing: the 500 and 800 Series washers list 51 dBA, the 300 Series 52.
- Spinning: the 300 Series lists 72 dBA, the 500 and 800 Series 75. The 300 tops out at 1,400 rpm and the others at 1,600.
- Drying: the 500 and 800 Series heat pump dryers list 62 or 63 dBA, the 300 Series condensation dryer 67.
The 500 Series pair wins two of the three, including the dryer, which runs a full cycle above the washer after every load. The 300 Series pair wins the loudest minutes at the bottom of the stack. The 800 Series pair prints exactly the 500 Series figures.
Which pair fits depends on who is near the closet. If someone sleeps on the floor below, the spin is the part to keep down, and the 300 Series spins 3 dBA quieter. If a bedroom sits on the other side of the closet wall, the dryer's whole cycle matters more than the end of the wash, and the 500 Series dryer lists 4 dBA less than the 300 Series dryer. Stock may decide before either: on 13 October Bosch's store showed the 300 Series washer and the 500 Series dryer out of stock, and both 800 Series machines in stock.
Why Beko and ASKO sit on their own lines
Beko's spec sheet labels match Bosch's word for word, and every Beko figure is higher: 52 against 51 washing, 76 against 75 spinning, 66 against 63 for the dryer. We still keep the Beko pair on a separate line rather than ranking it below Bosch's, because neither maker states whether its dBA describes sound power or sound pressure at some distance, and those two quantities cannot be converted into each other without the distance and the room. If both makers measured the same quantity, the Bosch 500 Series pair would be lower on all three counts; if they did not, the gaps tell you nothing.
ASKO's label is different again: "Noise level drying", in dB(A). It names the drying cycle, where Bosch and Beko name none, and it states no quantity either. So the T3HW's 61 cannot be placed above Bosch's 63 or below it. And because ASKO prints nothing for its washers, an ASKO stack has a number for its top half only, which is why the ASKO pair comes after the two pairs with figures for both machines.
The kit belongs to the dryer maker
Every pair here stacks only on its own maker's hardware, and Bosch says what happens otherwise: "If this appliance is not correctly installed in a washer-dryer stack, the installed appliance may fall." Its manuals allow only the dryer maker's own connection kit, and rule out stacking machines from different makers or of different depths and widths.
Bosch lists three kits for each series, which its spec sheets call "Necessary only when stacking a matching Bosch dryer on top of washer": one with a pull-out shelf, one without, and one with brackets. For the 300 Series those are the WTZ11400UC, WTZ20410UC and WTZSB30UC; for the 500 Series the WTZ27500UC, WTZ27510UC and WTZSB30UC; for the 800 Series the WTZ2750XUC, WTZ2751XUC and WTZSB3XUC. All are sold separately.
Beko puts kit 2974640200 in the box with the HPD24414W2 and says it "should be installed by the Authorized Service provider". ASKO packs a two-part tipping guard and plastic front footrests inside the T3HW's drum; part B of the guard turns 180 degrees to suit the depths of washer and dryer, and ASKO says it "cannot be installed on washing machines from other brands". Miele's WTV502 and WTV512 kits are optional accessories, and Electrolux names STACKIT7X for its full-size pair.
Two rules hold across the makers. The dryer goes on top, never the washer: Bosch's 300 Series dryer manual says "Do not stack washer on top of dryer", ASKO says its washers "should never be stacked on a counter or a dryer", and Electrolux lists the top of a dryer among the places not to install its washer. And the stack stays on the floor: Bosch forbids setting a stack on a platform, where it may tip over, and Electrolux says not to stack a dryer on a washer already installed on a pedestal.
What the spin does to the machine on top
A stacked dryer stands on the one appliance in the house that is built to shake. Bosch's 300 Series dryer manual makes that the last check before stacking: "Ensure washer transportation bolts have been removed and washer does not vibrate excessively." Bosch's washer manuals give three causes for a washer that is "vibrating, 'wandering', and making loud noises during the spin cycle": it is not aligned, its feet are not fixed, or the transit bolts are still in.
The weight on top also changes what the floor carries. Bosch's spec sheets put the 500 Series washer at 182 lbs and its dryer at 126, which adds up to 308 lbs before any water or laundry; the 300 Series pair adds up to 257. Beko says a washer with the HPD24414W2 on top "may reach 397 lbs (180 kg) when they are full. Therefore, the floor must be capable of carrying the load placed on it!" ASKO says all its washers can bear the weight of an ASKO dryer.
Beko's manual is the firmest about the floor under its washer: "a strong solid concrete floor to prevent vibration, noise or movement in case of load unbalance". It does not recommend a wooden or soft floor, and on a wooden or frame floor it asks for reinforcement and, if possible, a corner of the room. For a wooden joist floor, Bosch wants a water-resistant board of 1.18 inches or more screwed down under the washer.
Spin speed is where two makers' sentences pull against each other in a stack. ASKO: "the higher the spinning rate in the spin cycle, the higher the noise and the lower the residual moisture content." Bosch, in its energy advice: "Set the maximum spin speed if you want to dry the laundry in a tumble dryer afterwards." A slower spin quiets the bottom machine and hands wetter laundry to the one on top. None of these makers gives a decibel figure for a slower spin, so neither side of that trade has a number.
Leveling a stack from the floor up
A stack is leveled twice, and the washer comes first, because the dryer can only be as level as the top it stands on. Bosch says to align its washers "In order to reduce noise and vibrations, and to prevent the appliance from moving", check them with a spirit level and tighten the lock nuts with a 17 mm wrench. Beko's manual has the lock nuts loosened by hand, the feet turned until the washer "stands level and firmly", and every lock nut tightened again. ASKO calls a leveled W3W with tightened locknuts "essential" against excessive vibration in the spin.
The dryer's feet are the second leveling, and ASKO's are the only instructions we read that spell it out for a stack. For the T3HW on an ASKO washer, its instructions say to tighten all four dryer feet completely, unscrew the front two by exactly one turn and the rear two by exactly two, then lock both halves of the tipping guard with the fronts of the two machines aligned. ASKO adds that incorrect leveling "may cause vibration, appliance sliding across the floor, and loud operation", and that the warranty does not cover it.
Bosch's 300 Series dryer manual explains why the feet should stay short: "The more the feet are extended, the more vibration the dryer will experience." It asks for all four feet to press with equal pressure, which it says "will help assure the quietest, most vibration-free use of your dryer", and for a press on each corner of the top to check for wobble. Beko's guide makes level, balanced feet the condition for the HPD24414W2 to run "more silently and vibration-free".
A heat pump dryer at the top of the stack
Bosch's 500 and 800 Series dryers, Beko's HPD24414W2 and ASKO's T3HW are heat pump dryers, which puts a compressor on top of the washer. Bosch's troubleshooting table lists "Humming, whirring, or pumping noises" as "Not a fault" when the compressor, compressor ventilation or condensation pump is running, and its manual asks you to let the dryer rest for two hours after transport before you run it. The 300 Series WPA12100UC has no compressor, and on Bosch's list it is still the louder dryer, at 67 dBA, while drawing 2,520 W against 900 W for the heat pumps.
Where the water goes is easier to plan before the dryer is up there. Bosch's heat pump dryer drains "by default into the waste water system using the water outlet hose", and a Y-distributor accessory connects the washer's hose "to the same siphon outlet", so one drain connection behind the stack serves both. Beko's stacking drawing shows a separate drain hose for each machine. ASKO's T3HW holds up to 1.7 gallons in its water tank.
Height, depth and the closet door around a stack
Every Bosch stack, whichever series, needs at least 67 3/4 inches of height on its kit, and Bosch wants 6 1/4 inches clear above it, which puts the first shelf at 74 inches or higher. Beko's stacked height is the same 67 3/4 inches. A Miele stack on a WTV kit stands 67 11/16 inches tall, or 71 1/4 inches on the kit with a drawer.
Depths differ more than heights, and the deeper machine is the dryer in every pair here. Bosch's 500 Series washer is 25 1/2 inches deep under a 26 inch dryer, and the 300 Series washer 24 1/4 inches under a 25 inch dryer. Beko's washer is 22 13/16 inches deep under a 27 1/2 inch dryer. ASKO's W3W is 22 1/2 inches deep under the 24 13/16 inch T3HW, a combination its tipping guard is built to take.
The closet door is where Bosch's two kinds of stack differ most. With the 300 Series condensation dryer on top, Bosch asks for louvers of 63 square inches at the top and the bottom of the door. With a heat pump dryer on top, it wants the door cut 1 1/4 inches short at the top and the bottom over a width of at least 24 inches, about 30 square inches each. Beko's stacked-closet drawing calls for two openings adding up to 72 square inches, and Electrolux wants 120 square inches when a washer and dryer share a closet. Every one of those openings is also a way out for the sound, and Bosch warns that with the doors closed you should "expect long drying times".
One dryer outlet or two circuits
Bosch's pairs can run from the dryer receptacle a laundry closet already has. Both machines take 208 to 240 volts on NEMA 6-15 plugs, and each Bosch dryer comes with a WTZPA20UC adapter that fits a standard 4-prong, 30 A NEMA 14-30R receptacle and feeds both; two separate NEMA 6-15R or 6-20R receptacles are the alternative.
Beko's pair needs two kinds of power. The HPD24414W2 has a 4-wire NEMA 14-30R cord for 208/240 V, and the WFTV10733XC's rating label says 120 VAC at 10 A. Beko's spec sheet says the washer can plug into the matching dryer on one 30 A circuit, but the washer's manual says to connect it directly to a 120 V wall outlet, and the manual is the document we would follow.
ASKO's T3HW wants a 30 A circuit at 208 to 240 volts, and the W3W a 15 A fuse at the same voltage. Of the heat pump pairs here, only Miele's, the WXC280 washer and TXB360WP dryer, runs both machines on standard 120 V, 15 A outlets, and Miele prints no figure for either.
How we chose
We counted a pair only when the maker names the two machines as partners and names the hardware that holds the dryer on top: Bosch's series kits, Beko's kit 2974640200, ASKO's tipping guard, Miele's WTV kits and Electrolux's STACKIT7X. For each pick we went through three of the maker's documents, the US product page, the specification sheet and the installation or use and care manual, on 10 or 13 October 2026, and copied every figure with the label the maker printed beside it.
We ranked figures against each other only where the label, the unit and the phase of the cycle match within one maker's documents, which is why Bosch's three pairs are ranked and the Beko and ASKO pairs each stand on their own line. We put pairs with a figure for both machines above a pair with a figure for the dryer only, and left out figures we could not tie to the machine on sale, such as Blomberg's tables for older models, along with Equator's unweighted figure for one program. If you are buying only one of the two machines, start with the compact washers or the compact dryers.
Each figure here was copied from a maker's page, sheet or manual, and a machine whose maker prints nothing is shown with no figure. We did not measure any of these washers or dryers ourselves.
