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LENNOX rates the MMDD as medium static, slim profile, and the MDDD as high static. The MMDB, on R-410A, rounds out the range. Pick a size and a mounting: we show you the heads LENNOX makes, their published static pressure and their certified system.
MDDD, MMDD and MMDB, from 9,000 to 48,000 BTU/h. “M6” heads go on a multi-zone outdoor unit only.
Matches come from the LENNOX documents; certified heat and SEER2 and HSPF2 ratings from the ENERGY STAR registry for Canada.
It is the resistance your ducts put up against the air. The longer and more branched the network, the more the head has to overcome: we look at it on site.
in. w.c.: inches of water column. For the MMDD, LENNOX prints three values without saying which one is the factory setting.
Both LENNOX pressure classes are here: the MMDD, slim, and the MDDD, high static. The MMDB is the R-410A option.
Our product page says “multi-zone only”. ENERGY STAR still certifies it as single zone with the MMLD018 (record 3799323).
The MMD is LENNOX’s other ducted indoor unit: an air handler that can take an electric heat kit. Here is what changes, rating by rating.
Pink rows are the differences. Ratings: ENERGY STAR (Oct. 28, 2026); pressures, sound and kits: LENNOX submittals 496383 and 496388 (Jan. 2025), form 211233 (Sept. 2026). See the MMD air handlers.
Every LENNOX source says it: the MDDD is the “high static” ducted head, the MMDD the “medium static, slim-form” one. The MMDB, on R-410A, is medium static too.
LENNOX, forms 211035 and 211088 (Sept. 2025); submittal 496383 (Jan. 2025); bulletin 211040 (April 2024).On a ducted unit the wireless remote is optional: LENNOX supplies it only with wall units and floor consoles. For the MMDD, its sheet also requires the VCTRL10P-1 receiver-display.
LENNOX, form 211088, p. 4; form 211035.The MMDD S6 goes on a single-zone or a multi-zone outdoor unit. The MDDD comes in two versions: S6 for single zone, from 9,000 to 48,000, and M6 for multi-zone, from 9,000 to 18,000.
LENNOX, forms 211076, p. 12, and 211075, p. 10.What LENNOX publishes for each head in our catalogue. “Not published” means: absent from the LENNOX documents we read.
| Model | LENNOX class | Mounting | System (AHRI) | Static pressure | Indoor sound, low · med · high |
|---|---|---|---|---|---|
| MDDD018S6 | High static | Our page: multi-zone only * | MMLD018 + MDDD018 · 215810025 * | Not published | Not published |
| MDDD024S6 | High static | Single zone | MMLD024 + MDDD024 · 215810029 | Not published | Not published |
| MDDD030S6 | High static | Single zone | MMLD030 + MDDD030 · 215810031 | 0.1 min. · 0.58 std · 0.79 max. in. w.c. | 33 · 37 · 41 dB(A) |
| MDDD036S6 | High static | Single zone | MMLD036 + MDDD036 · 215810032 | Not published | Not published |
| MDDD048S6 | High static | Single zone | MMLD048 + MDDD048 · 215810033 | Not published | Not published |
| MDDD009M6 | High static | Multi-zone only | Multi-zone system | Not published | Not published |
| MDDD012M6 | High static | Multi-zone only | Multi-zone system | Not published | Not published |
| MDDD015M6 | High static | Multi-zone only | Multi-zone system | Not published | Not published |
| MDDD018M6 | High static | Multi-zone only | Multi-zone system | Not published | Not published |
| MMDD009S6 | Medium static · slim | Single or multi-zone | MMLD009 + MMDD009 · 216581322 | 0 · 0.10 · 0.24 in. w.c. | 26 · 30 · 33 dB(A) |
| MMDD012S6 | Medium static · slim | Single or multi-zone | MMLD012 + MMDD012 · 216581323 | 0 · 0.10 · 0.24 in. w.c. | 27 · 31 · 34 dB(A) |
| MMDD018S6 | Medium static · slim | Single or multi-zone | MMLD018 + MMDD018 · 215810026 | 0 · 0.10 · 0.24 in. w.c. | 28 · 32 · 35 dB(A) |
| MMDB009S4-2P | Medium static · R-410A | Single zone | MPC009 + MMDB009 · 207683503 † | 0 to 0.16 in. w.c. | 27 · 28.5 · 33.5 dB(A) |
| MMDB012S4-2P | Medium static · R-410A | Single zone | MPC012 + MMDB012 · 207683504 † | 0 to 0.16 in. w.c. | 31 · 34.5 · 38 dB(A) |
| MMDB018S4-2P | Medium static · R-410A | Single zone | MPC018 + MMDB018 · 207683505 † | 0 to 0.40 in. w.c. | 35 · 37.5 · 40 dB(A) |
| MMDB024S4-2P | Medium static · R-410A | Single zone | MLB024 + MMDB024 · 207683527 † | 0 to 0.64 in. w.c. | 37 · 41 · 44 dB(A) |
| MMDB036S4-1P | Medium static · R-410A | Single zone | MPB036 + MMDB036 · 10528567 (bulletin) | 0 to 0.64 in. w.c. | 40.5 · 43.5 · 48 dB(A) |
| MMDB048S4-1P | Medium static · R-410A | Our page: multi-zone only * | See note * | 0 to 0.64 in. w.c. | 49 · 50 · 52 dB(A) |
Built-in condensate pump: MMDD and MMDB, 27-1/2 in. lift. MMDD: at least 7/8 in. (22 mm) between the ceiling and the bottom of the unit (form 211088).
* Single or multi-zone: the MDDD018S6 and the MMDB048 are marked “multi-zone only” on our product pages. LENNOX certifies MMLD018 + MDDD018S6 as single zone (AHRI 215810025); the April 2024 MLB bulletin pairs the MMDB048 as single zone with the MLB048S4S-2P (AHRI 211034449).
† MMDB AHRI: ENERGY STAR registry numbers, the ones on our product pages. The 2024 LENNOX bulletins print other numbers for the same pairs: 211034423, 211034424, 211034425, 211034447.
Amounts from our product pages, read live; Hydro-Québec list of October 6, 2026 at our last check. Indicative amounts: only Hydro-Québec confirms the assistance granted.
LogisVert residential participation guide, version 1.10, September 15, 2026. Our LogisVert page.
LENNOX rates the MMDD as medium static, slim profile, and the MDDD as high static. The MMDD publishes three static pressure values, up to 0.24 in. w.c.; for the MDDD, LENNOX publishes the pressure for the 30,000 only: up to 0.79 in. w.c. The longer and more branched the ductwork, the more pressure it takes. We look at it on site before choosing.
No: it is a heat pump. With the MMLD outdoor unit it heats and cools, and LENNOX gives the MMLD a heating range down to -25 °C (-13 °F). ENERGY STAR certifies the 18,000 MMDD with the MMLD018 as cold climate for Canada: 16,200 BTU/h at -8.3 °C.
At LENNOX, M6 at the end of the number means multi-zone only: the 9,000 to 18,000 MDDD M6 go on an MMLD multi-zone outdoor unit. As of this page’s date, no LENNOX multi-zone outdoor unit is in our catalogue. Two product pages also carry the mention without being M6: the MDDD018S6, which LENNOX and ENERGY STAR certify as single zone with the MMLD018 (AHRI 215810025), and the MMDB048, which the April 2024 LENNOX MLB bulletin pairs as single zone with the MLB048S4S-2P (AHRI 211034449).
Yes, built in, with a 27-1/2 in. lift according to LENNOX. The MMDB has one too. For the MMDD, LENNOX requires at least 7/8 in. (22 mm) between the ceiling and the bottom of the unit.
LENNOX extended warranty EW900011-01 gives 12 years on parts for the MDDD and MMDD heads, and 12 years on parts and compressor for the MMLD outdoor unit. In Québec, registration is not required. Labour is not covered by LENNOX, and the extended warranty stays with the original owner. For the MMDB, two LENNOX documents disagree on the scope of the basic warranty: we do not show it here.
The LogisVert guide requires an ENERGY STAR certified heat pump of at least 12,000 BTU/h nominal. The MMLD + MDDD and MMLD + MMDD systems of 12,000 BTU/h and up are listed by ENERGY STAR for Canada, as cold climate. The indicative amount shows on the product page when it is recorded there. Only Hydro-Québec confirms the assistance granted.
RBQ subclass 15.8 covers duct networks. AirGreen’s RBQ licence holds 15.8, 15.10 and 16.
We don’t guess it over the phone. We come and look at the house, the existing ducts, the insulation and the current heating, then we suggest the head and the size. The estimate is free.
We look at your ducts and the room in the ceiling or basement, choose the head and the size with you, and the quote carries the system’s AHRI number and the indicative LogisVert amount when the unit qualifies.
Hydro-Québec does not solicit anyone by phone or door to door for LogisVert. A call “from Hydro-Québec” selling a heat pump? Hang up.
LogisVert amounts are indicative: only Hydro-Québec confirms the assistance granted. Price on quote. Free in-home estimate.