MRCOOL, the Hickory, Kentucky brand behind the DIY mini-split kits that come with pre-charged line sets, prints a noise figure for nearly every current US ductless system it sells: an indoor figure for each of five fan speeds and one outdoor figure. Its catalog, brochures and submittal sheets repeat the same numbers, so its line can be ranked within itself, as long as size, unit type and fan speed are kept together.
Below is every current system in MRCOOL's September 2026 catalog with a published figure, the five DIY lines and the contractor-installed Advantage and Olympus, grouped so that only like is compared with like. To see how MRCOOL sits against other brands, see our quietest mini-splits guide; we do not rank other brands here.
Our picks are listed above, with full specifications for each.
How MRCOOL rates noise
Every MRCOOL specification table has an indoor row, "Indoor Noise Level (Turbo/Hi/Mi/Lo/Si)", with five figures in dB(A), and an outdoor row, "Outdoor Noise Level", with one. The Advantage and Olympus submittal sheets print the same numbers as "Indoor Noise Level (Turbo/H/M/L/Si)" in dBA. The five speeds are the same in every line, so those are the labels we rank on, reading H, M and L as Hi, Mi and Lo.
Si is Silence. MRCOOL's service manuals say that with it on, "the indoor unit will run at a faint breeze (1% fan speed), which reduces noise to the lowest possible level." The remote manual says it comes on when the fan button is held for more than 2 seconds, and warns that "it may result in insufficient cooling or heating capacity." Turbo, by the same manual, blows "with the strongest wind setting". So Si is for holding a room at temperature overnight, and Turbo is for pulling a hot room down.
What MRCOOL does not print, next to any figure we rank, is a mode, a distance or a standard. The submittals give the capacity ratings their conditions, "Indoor: 80°F DB/67°F WB" and "Outdoor: 95°F DB/75°F WB" for cooling, but the noise rows carry none, and the catalog and nearly every brochure mark their specifications as preliminary and subject to change in mass production. So we treat every figure as mode not stated.
Two service manuals go further, for their noise charts rather than the table figures. The Olympus E Star manual says of its outdoor units, "Sound is measured at 3.25ft/1.0m away from the center of the unit," adding "Data is valid at free field condition," with the microphone drawn at half the unit's height. The DIY OuttaSight cassette manual gives 4.92 ft (1.5 m) from "the loudest location of the unit", though its drawing puts the microphone 1.4 m (4.59 ft) below the ceiling. Neither ties the dB(A) figures in the tables to those charts. Our main guide says MRCOOL gives no distance or standard, and for the figures ranked here that still holds. For why it matters when you line up brands, see comparing decibel ratings.
Which lines are current
MRCOOL's catalog, version V 09.16.26, and the ductless menu on MRCOOL's website list seven lines. Older pages buyers still find, such as the DIY 4th Gen and an earlier Advantage, now redirect to the 5th Gen pages, and the Olympus Hyper Heat page no longer loads.
- DIY 5th Gen (model numbers starting DIY-): 9,000 to 36,000 BTU, the 9k and 12k on 115V, with a 25 ft pre-charged Quick Connect line set and heating down to -13°F by its manual.
- DIY Hyper Heat (DIYHH-): 12,000 and 18,000 BTU condensers with an "Operational Range" of -22°F to 122°F, paired with the DIY wall units.
- DIY Select (DIYS-): the budget DIY line, 9,000 to 24,000 BTU, with an 11.5 ft line set.
- DIY Easy Pro (EZPRO-): a second DIY line with an 11.5 ft line set, 9,000 to 24,000 BTU, with the same noise figures as the DIY Select.
- DIY OuttaSight ceiling cassette (DIYCASSETTE): indoor units of 6,000 to 18,000 BTU for the DIY condensers.
- Advantage 5th Gen (A-): contractor installed, 9,000 to 36,000 BTU, with 115V and 230V versions at 9,000 and 12,000.
- Olympus E Star (O-ES-): contractor installed, 9,000 to 24,000 BTU, plus Olympus multi-zone condensers with wall, cassette and ducted heads.
MRCOOL also sells the DIY Hybrid air handler, a ducted unit for the 24,000 and 36,000 BTU DIY condensers, and its Universal, Signature and VersaPro central systems. Those are ducted, so we leave them out.
Every 9,000 BTU wall unit, quietest first
All six are rated 9,000 Btu/h in cooling. Figures are in dB(A), mode not stated.
- Si: DIY 5th Gen, DIY Select, DIY Easy Pro and Advantage 115V 18; Advantage 230V 18.5; Olympus E Star 19.5.
- Lo: Olympus E Star 20.5; DIY Select and Easy Pro 22; Advantage 230V 23; DIY 5th Gen 24; Advantage 115V 25.
- Mi: DIY Select and Easy Pro 31; Advantage 230V 31.5; Olympus E Star 33; DIY 5th Gen and Advantage 115V 33.5.
- Hi: DIY Select and Easy Pro 35; Advantage 230V 35.5; Advantage 115V 37.5; Olympus E Star 38; DIY 5th Gen 39.5.
- Turbo: Olympus E Star 38; Advantage 230V 40.5; DIY 5th Gen, DIY Select, Easy Pro and Advantage 115V 43.
The spread on Si is 1.5 dB(A); on Hi it is 4.5. At this size the speed the head will actually sit on matters more than its Si figure. Our bedroom mini-split guide explains why the bottom two speeds matter most at night.
Every 12,000 BTU wall unit, quietest first
All seven are rated 12,000 Btu/h in cooling.
- Si: DIY Select, Easy Pro and Advantage 115V 17.5; DIY 5th Gen and Hyper Heat 18; Olympus E Star 19.5; Advantage 230V 21.
- Lo: Olympus E Star 22; Hyper Heat and Advantage 230V 22.5; DIY 5th Gen 24; Advantage 115V 25; DIY Select and Easy Pro 25.5.
- Mi: Advantage 230V 32; Advantage 115V and Olympus E Star 32.5; DIY 5th Gen 33.5; Hyper Heat 34; DIY Select and Easy Pro 35.
- Hi: Olympus E Star 36.5; Advantage 230V 38; DIY 5th Gen 39.5; Hyper Heat, DIY Select and Easy Pro 40; Advantage 115V 40.5.
- Turbo: DIY 5th Gen 43; Advantage 230V 44; DIY Select and Easy Pro 44.5; Advantage 115V 45; Hyper Heat 45.5; Olympus E Star 47.
The DIY Select and Easy Pro lead on Si and list the highest Lo and Mi figures at this size. The Advantage shows a pattern of its own: at 9,000 and 12,000 BTU the 230V version lists less than the 115V one on Turbo, Hi, Mi and Lo, and more on Si.
18,000, 24,000 and 36,000 BTU wall units
18,000 BTU, all rated 18,000 Btu/h in cooling, Turbo / Hi / Mi / Lo / Si: Advantage "50.5/45/36/24/19"; DIY 5th Gen "54.5/44.5/40.5/30.5/19"; Hyper Heat "54.5 / 45 / 40 / 30.5 / 20.5"; Olympus E Star "49.5 / 45 / 38 / 31.5 / 19.5". The Advantage is lowest on Lo, by 6.5 dB(A), and on Mi; the DIY 5th Gen ties it on Si and is lowest on Hi; the Olympus is lowest on Turbo.
The DIY Select 18k and Easy Pro 18k are rated 17,000 Btu/h in cooling, so we list them apart: both "46.5 / 43 / 36.5 / 30 / 18.5". Our living room mini-split guide sets the DIY Select 18k beside 18,000 BTU heads; on MRCOOL's sheet it is a size smaller in cooling.
24,000 BTU, rated 24,000 Btu/h: Olympus E Star "54.5 / 43.5 / 38.5 / 27 / 16"; Easy Pro "51.5/45.5/40.5/26.5/21.5"; Advantage "54/45/41.5/27/21.5"; DIY 5th Gen "54/48/43/33.5/20". The Olympus is lowest on Si, Mi and Hi and highest on Turbo; the Easy Pro is lowest on Lo and Turbo; the DIY 5th Gen is highest on Lo, Mi and Hi. The DIY Select 24k lists the Easy Pro's figures but is rated 23,000 Btu/h, so it sits apart. Our quietest mini-splits guide ranks the DIY Select 12k's 17.5 dB(A) on Si lowest among the systems it covers; it does not cover the Olympus E Star, whose 24,000 BTU head lists 16.
36,000 BTU: DIY 5th Gen "55.5/49.5/43.5/38/27.5" and Advantage "56.5/50.5/44.5/34/28". The DIY lists less at every speed but Lo, where the Advantage lists 4 dB(A) less.
Ceiling cassettes and ducted units
These are ranked only within their own type.
DIY OuttaSight cassette (DIYCASSETTE), Turbo / Hi / Mi / Lo / Si: 6,000 BTU "46.5 / 37.5 / 35.5 / 26 / 23.5"; 9,000 "38 / 38 / 36 / 33 / 24"; 12,000 "41 / 41 / 37 / 33 / 24"; 18,000 "44 / 44 / 41.5 / 31 / 26". It is a long, narrow unit, 50.3 by 13.1 in, that fits between 16 inch joists. MRCOOL's AHRI certificates pair the 12,000 BTU cassette with the Hyper Heat 12k condenser and the 18,000 BTU one with the DIY 5th Gen or Hyper Heat 18k. Its service manual has a catch for multi-zone buyers. Of Silence, it says: "When matching with a multi outdoor unit, this function is disabled." On a multi-zone system, then, its Si figure does not apply.
Olympus ceiling cassette (CASSETTE09HP-230C and up), Turbo / H / M / L / Si: 9,000 BTU "42.5/40/37.5/26/24"; 12,000 "46/43.5/40.5/27.5/26"; 18,000 "48/44.5/41/27.5/23.5"; 24,000 "48.5/45/42.5/33.5/33.5". These square cassettes are sold as heads for the Olympus multi-zone condensers. MRCOOL's multi-zone brochure says the cassette's "indoor fan operates down to a quiet 23.5 dB", which is the 18,000 BTU figure; the 9,000 and 12,000 BTU cassettes list more on Si.
Olympus ducted (DUCT-09HP-230B and up), Turbo / H / M / L / Si: 9,000 BTU "32.5/32.5/31/29.5/23"; 12,000 "36/36/34.5/32.5/25.5"; 18,000 "40/40/39/38/32"; 24,000 "40/40/37/35/29.5". What reaches the room from a ducted unit also depends on the ductwork, so we keep these apart from the ductless heads.
Every single-zone outdoor unit, quietest first
These are the figures your neighbors hear. Compare them only with each other, within a size.
- 9,000 BTU: DIY 5th Gen, DIY Select and Easy Pro 54; Olympus E Star 56.
- 12,000 BTU: DIY 5th Gen, DIY Select and Easy Pro 54; Olympus E Star 56; Hyper Heat 56.5.
- 18,000 BTU: Hyper Heat 58; DIY 5th Gen 58.5; Olympus E Star 59.
- 24,000 BTU: DIY 5th Gen 58.5; Easy Pro 61; Olympus E Star 61.5.
- 36,000 BTU: DIY 5th Gen 60.5.
- Rated apart: DIY Select and Easy Pro 18k (17,000 Btu/h) 55; DIY Select 24k (23,000 Btu/h) 61.
MRCOOL's catalog and Advantage brochure label the Advantage figures "Outdoor noise level (Hi)", while its submittals print the same numbers with no label, so we list them apart: 52.5 for the 9,000 BTU 115V system and 53.5 for the 230V one, 54 for both 12,000 BTU systems, 56 at 18,000, 59.5 at 24,000 and 60.5 at 36,000. On paper those are the lowest outdoor numbers MRCOOL prints at 9,000 and 18,000 BTU, but with a different label we cannot call them the quietest.
The quietest heads indoors are often the loudest outside. The Olympus E Star leads on Lo at 9,000 and 12,000 BTU and on Si at 24,000, and its outdoor units list the highest figure at 9,000, 18,000 and 24,000 BTU.
Multi-zone outdoor units and heads
MRCOOL's DIY multi-zone condensers list 60 dB(A) for the 3-zone DIY-MULTI3-18HP230D-O (18,000 Btu/h), 61 for the 4-zone DIY-MULTI4-27HP230D-O (26,000), and 64 for the 5-zone DIY-MULTI5-36HP230D-O (34,000) and both 6-zone units, DIY-MULTI6-48HP230D-O (43,000) and DIY-MULTI6-55HP230D-O (47,000). The Olympus multi-zone condensers list 59.5 for the MULTI3-18HP230C-O (18,000), 61 for the MULTI4-27HP230C-O (27,000), 64.5 for the MULTI5-36HP230C-O (36,000) and 63 for the MULTI6-48HP230C-O (47,000). Where the rated capacity matches, the Olympus lists less: 59.5 against 60 at 18,000 Btu/h, and 63 against 64 at 47,000.
The Olympus wall heads list the same five figures on a multi-zone system as on the single-zone E Star. MRCOOL prints no figures of their own for the DIY multi-zone wall heads, DIY-06, DIY-09 and DIY-12-HP-WMAH-230D25-O; the 12,000 BTU one appears only as the indoor unit of the Hyper Heat 12k, at "45.5 / 40 / 34 / 22.5 / 18".
Where MRCOOL's own documents disagree
We rank on the figures in MRCOOL's catalog, brochures and submittals, which agree wherever more than one of them prints a figure. A few other things do not add up.
- One head, two sets of figures. The DIY 5th Gen 18k and the Hyper Heat 18k use the same indoor unit, DIY-18-HP-WMAH-230D25-O, but the catalog lists "54.5/44.5/40.5/30.5/19" with the standard condenser and "54.5 / 45 / 40 / 30.5 / 20.5" with the Hyper Heat.
- Airflow that does not move with noise. The Olympus E Star submittals give the 9,000 and 12,000 BTU heads the same airflow at every speed, yet list 38 dB(A) on Turbo for one and 47 for the other. The 9k prints 38 on both Turbo and Hi, at 441.4 and 323.7 CFM. On the 18,000 and 24,000 BTU heads, Lo and Si share almost the same airflow but are 12 and 11 dB(A) apart. We quote these figures as printed; read the Olympus figures with that in mind.
- The Hyper Heat line set. The catalog lists an "11.5 Ft Quick Connect® Line Set" for the Hyper Heat, as our main guide reports. The Hyper Heat brochure says installation uses "the 25-foot pre-charged QuickConnect® line set", and MRCOOL's spec data gives 25 ft.
- A label that comes and goes. The Advantage outdoor figures carry "(Hi)" in the catalog and brochure but no label in the submittals.
- Capacity. MRCOOL's spec data lists the DIY 5th Gen 24k bundle at 23,000 BTU; its catalog, brochure and product page say 24,000, which we use.
- Price. Our earlier MRCOOL guides say MRCOOL shows no price on its own site. On October 10, 2026, its DIY 5th Gen, DIY Select and DIY Easy Pro pages did; see the price section below.
What changes the noise between models
Size, above all. On Mi, the DIY 5th Gen goes from 33.5 dB(A) at 9,000 and 12,000 BTU to 40.5 at 18,000, 43 at 24,000 and 43.5 at 36,000. Si moves far less, from 18 to 20 up to 24,000 BTU. If a smaller head will do the room, it will be quieter at the speeds you hear in the evening.
Which speed you use. At 9,000 BTU the DIY Select and Easy Pro lead on Mi and Hi, and the Olympus E Star on Lo. At 24,000 BTU the Olympus leads on Si, Mi and Hi, and the Easy Pro on Lo. Pick by the speed the head will actually run at.
Line, less than price suggests. The cheapest systems MRCOOL prices, the DIY Select and Easy Pro, are the quietest 9,000 BTU heads on Mi and Hi. The contractor-installed Advantage is the quietest 18,000 BTU head on Lo and Mi. The DIY 5th Gen, with the longest warranty and line set of the DIY lines, leads indoors only here and there: on Turbo at 12,000 BTU, on Hi at 18,000, and on four speeds at 36,000, where only the Advantage competes. Its outdoor units, though, list the lowest or tied lowest unlabelled figure at 9,000, 12,000 and 24,000 BTU.
Voltage, on the Advantage. At 9,000 and 12,000 BTU the 230V Advantage lists less than the 115V one on four speeds and more on Si, by 0.5 and 3.5 dB(A).
Night settings MRCOOL describes
Sleep. The DIY 5th Gen service manual says sleep mode moves the set temperature 1.8°F (1°C) an hour for two hours, and that "After 2 hours, the temperature stops rising and the indoor fan is fixed at a low speed." MRCOOL prints no figure for that speed. Our bedroom guide, which read the owner's manual, describes sleep mode only as a change of set point; the service manual adds the fixed low fan speed. The Advantage page says its sleep setting is "designed for quieter operation, reduced energy use, and more restful sleep."
The display. The MS-5 remote manual, which MRCOOL links for the DIY 5th Gen, DIY Select, Easy Pro and Advantage, says: "Press the LED button to turn on and turn off the display of the indoor unit."
MRCOOL's quiet claims, in its words
The Olympus E Star brochure says: "With indoor noise levels as low as 16 decibels, you'll barely know it's there." That is the 24,000 BTU head on Si; the 9,000 to 18,000 BTU E Star heads list 19.5. Its product page promises "Ultra-Quiet Operation". The Olympus multi-zone brochure says the ceiling cassette's "indoor fan operates down to a quiet 23.5 dB". The DIY Select and Easy Pro brochures list "Quiet operation for living spaces", and the catalog lists "Quiet Operation" among the Advantage, Olympus and OuttaSight features. We found no outdoor quiet mode in MRCOOL's documents.
The DIY manual adds advice that matters as much as any figure: do not install the outdoor unit "where noise from the unit will disturb others", and on a wall bracket, "If allowed, install the unit with rubber gaskets to reduce vibrations and noise." Our heat pump noise explainer lists the sounds makers say are normal, and our cold-climate mini-split guide keeps the Hyper Heat in a group of its own because MRCOOL gives no heating-mode figure.
What 16 to 64.5 dB(A) means at home
Every 10 dB(A) sounds roughly twice as loud, so a DIY 5th Gen 12k on Mi at 33.5 should sound about twice as loud as the same head on Lo at 24, if the conditions match. Our decibel chart puts these figures next to everyday sounds, and how quiet is quiet enough gives targets by room. For how a maker that states its mode and microphone position reports the same kind of figure, see our Daikin mini-split decibels page; Pioneer, like MRCOOL, gives neither.
Price, warranty and installation
MRCOOL now shows a price for its DIY lines, labelled "As Low As". On October 10, 2026, its pages showed the DIY 5th Gen at $2,329 (9,000 BTU), $2,359 (12,000), $2,909 (18,000), $3,329 (24,000) and $3,769 (36,000), each a bundle with the condenser, air handler, line set, DIYPRO cable and remote. They showed the DIY Select at $1,249, $1,399, $1,690 and $1,899, and the DIY Easy Pro at $1,487, $1,599, $1,806 and $2,109. The picks above use those prices. MRCOOL shows no price for the Hyper Heat, Advantage or Olympus, and the Advantage and Olympus are sold through dealers. Our earlier MRCOOL guides say MRCOOL shows no price on its own site; that is no longer true of these three DIY lines.
The warranties differ more than the noise figures. MRCOOL gives 5 years on parts and 7 on the compressor for the DIY 5th Gen, Hyper Heat, OuttaSight cassette and Olympus E Star; 3 and 5 for the Easy Pro; and 1 and 2 for the DIY Select and the Advantage. Every one of these warranties but the Advantage's says no registration is required; the Advantage's applies only to a unit bought from an authorized dealer. None covers labor. The Advantage page says "This system must be installed by a licensed HVAC technician", and the Olympus page says "an HVAC professional must install the Olympus mini-split system."
Every figure here is MRCOOL's own, quoted from its US catalog, brochures, submittal sheets and manuals with the fan speed it names. MRCOOL states no mode, distance or standard for any of them, and two of its service manuals warn that the sound level will vary with the room the unit is installed in. We did not measure any of these units ourselves.
