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AirGreen × TOSOT · Sold and installed by AirGreenTOSOT dual zone at AirGreenOne outdoor unit, two rooms, two compressor families: Lomo 23 and LomoPlus UltraHeat.
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TOSOT · Multi-zone · Dual zone · updated November 5, 2026

TOSOT dual zone: your pair of heads, compressor by compressor

Pick the head for each room, or a single head to start: you see which compressors take it, and what their TOSOT sheet says about it.

Pick my headsBook my free estimate
  • 9dual-zone compressors online
  • 2families: Lomo 23 and LomoPlus UltraHeat
  • 1head is enough to start, per both families’ sheets
  • $3,600LogisVert for the 42,000 UltraHeat compressor (list of October 7, 2026)
01 · Your pair, compressor by compressor

Pick one head per room, or a single head to start

You see which compressors take your heads. Lomo 23: the sheet read on October 28, 2026 gives the system output and each room’s share. LomoPlus UltraHeat: the sheet of November 4, 2024 lists the allowed combinations, with no output per combination.

Room 1 · BTU/h

Room 2 · BTU/h

Your heads: 12,000 + 12,000 = 24,000 BTU/h. 9 of 9 compressors accept it.

  1. ListedLomo 23 · 18,000TM18H4O · TOSOT sheet read on October 28, 2026System output per TOSOT: 16,718 BTU/h cooling, 20,062 BTU/h heating. Per room, heating: 10,031 BTU/h for the 12,000 head, 10,031 BTU/h for the 12,000 head.
  2. ListedLomo 23 · 24,000TM24H4O · TOSOT sheet read on October 28, 2026System output per TOSOT: 24,000 BTU/h cooling, 26,000 BTU/h heating. Per room, heating: 13,000 BTU/h for the 12,000 head, 13,000 BTU/h for the 12,000 head.
  3. ListedLomo 23 · 30,000TM30H4O · TOSOT sheet read on October 28, 2026System output per TOSOT: 24,000 BTU/h cooling, 26,000 BTU/h heating. Per room, heating: 13,000 BTU/h for the 12,000 head, 13,000 BTU/h for the 12,000 head.
  4. ListedLomo 23 · 36,000TM36H4O · TOSOT sheet read on October 28, 2026System output per TOSOT: 24,000 BTU/h cooling, 26,000 BTU/h heating. Per room, heating: 13,000 BTU/h for the 12,000 head, 13,000 BTU/h for the 12,000 head.
  5. ListedLomo 23 · 42,000TM42H3O · TOSOT sheet read on October 28, 2026System output per TOSOT: 24,000 BTU/h cooling (only this table was recorded). Per room, cooling: 12,000 BTU/h for the 12,000 head, 12,000 BTU/h for the 12,000 head.
  6. ListedLomoPlus UltraHeat · 18,000TM18H5O · list in the TOSOT sheet of November 4, 2024Heads 24,000 BTU/h ÷ compressor 18,000 BTU/h = 133% (above the 130% TOSOT recommends, below its 150% maximum).
  7. ListedLomoPlus UltraHeat · 24,000TM24H5O · list in the TOSOT sheet of November 4, 2024Heads 24,000 BTU/h ÷ compressor 24,000 BTU/h = 100% (within TOSOT’s recommended range, 50 to 130%).
  8. ListedLomoPlus UltraHeat · 36,000TM36H5O · list in the TOSOT sheet of November 4, 2024Heads 24,000 BTU/h ÷ compressor 36,000 BTU/h = 67% (within TOSOT’s recommended range, 50 to 130%).
  9. ListedLomoPlus UltraHeat · 42,000TM42H5O · list in the TOSOT sheet of November 4, 2024Heads 24,000 BTU/h ÷ compressor 42,000 BTU/h = 57% (within TOSOT’s recommended range, 50 to 130%).

LomoPlus UltraHeat: combination table in the TOSOT sheet of November 4, 2024, limited to the head sizes AirGreen offers (9,000 to 24,000 BTU/h); the ratio compares the sum of the heads with the compressor size, as TOSOT’s note does. Lomo 23: combination tables in the TOSOT sheets read on October 28, 2026, system output at AHRI test conditions (95 °F cooling, 47 °F heating). The final choice is made on site.

AirGreen × TOSOT

TOSOT dual-zone compressors, live

Each product page: outdoor model, AHRI number and the heads offered.
02 · Did you know

Three details in the TOSOT sheets that change a dual zone

01

Two 9,000 heads, more than their total

On the 42,000 BTU/h Lomo 23 compressor (TM42H3O), the sheet read on October 28, 2026 rates 19,500 BTU/h in cooling with two 9,000 heads: more than the two heads add up to.

TOSOT sheet TM42H3O.

02

One head is enough to start

Both families take a single-head system: 9,000 to 24,000 BTU/h on the 18,000 LomoPlus UltraHeat (sheet of November 4, 2024), and at least one head on the Lomo 23 units (sheets read on October 28, 2026).

TOSOT sheets TM18H5O to TM42H5O and TM18H4O to TM42H3O.

03

66 ft already charged

The 18,000 LomoPlus UltraHeat compressor ships with refrigerant for 66 ft of line; beyond that, its sheet calls for 0.2 oz per foot of liquid line.

TOSOT sheet TM18H5O (November 4, 2024).

03 · Side by side

Two 12,000 BTU/h rooms: one dual zone or two wall units?

The certified numbers, side by side. Two wall units mean two outdoor units and two circuits; a dual zone, one of each.

SystemOutdoor unitsCertified at -8 °CLogisVertRated heating (8.3 °C)
LomoPlus UltraHeat dual zone 24,000 (TM24H5O)117,900 BTU/h · outdoor unit$2,14826,000 BTU/h · system, sheet of November 4, 2024
Two Pular 25 12,000 wall units22 × 10,000 BTU/h = 20,000 BTU/h2 × $1,200 = $2,4002 × 12,000 BTU/h
Two LomoPlus UltraHeat 12,000 wall units22 × 10,300 BTU/h = 20,600 BTU/h2 × $1,236 = $2,4722 × 12,200 BTU/h

Sources: ENERGY STAR (-8 °C), Hydro-Québec’s list of October 7, 2026 (LogisVert), TOSOT sheet TM24H5O of November 4, 2024 and sheets TW12HXP2A1D and TW12HQ3D6D read on October 28, 2026 (rated heating).

04 · Multi-zone

The multi-zone pages, each with its question

R-410ATri-zoneYour line-set plan, checked against the sheet.R-410AFour zonesFour heads against one compressor.R-410AFive zonesWhat TOSOT really publishes for five rooms.R-410AUltraHeat dual zoneWhat the compressor keeps in deep cold.R-410AUltraHeat tri-zoneThe head trios TOSOT accepts.R-410ALomo 23 dual zoneStarting with a single head.R-410ALomo 23 tri-zoneThe compressor’s ceiling with three heads.TOSOTAll multi-zone unitsBoth compressor families, from 2 to 5 rooms.
AirGreen × TOSOT

The right model is chosen at your place, not on a grid

We look at the room, the insulation and the electrical panel, then we propose the model, the quote and the LogisVert amount that applies.

Book my free estimate514 316-2973
  • Sold and installed by AirGreenMontreal, Laval, Longueuil, South Shore and North Shore.
  • RBQ 5645-9605-01Subclasses 15.8 Ventilation, 15.10 Refrigeration and 16 Electricity.
  • LogisVertHydro-Québec never solicits by phone or door to door for LogisVert.
Sources

Sources and reading dates

  1. TOSOT, submittals TM18H5O, TM24H5O, TM36H5O and TM42H5O, dated November 4, 2024, tosot.com, read on November 5, 2026 (specifications, indoor-unit combination table and note on the capacity ratio).
  2. TOSOT, submittals TM18H4O, TM24H4O, TM30H4O, TM36H4O and TM42H3O, undated, read on tosot.com on October 28, 2026 (specifications and combination tables); these files were no longer online there on November 5, 2026.
  3. TOSOT, submittals TW12HXP2A1D and TW12HQ3D6D (rated heating of the wall units in table 03), read on October 28, 2026.
  4. TOSOT, “Heat Pumps” brochure in English, undated: note on the 24,000 BTU/h size with the 42,000 BTU/h compressors.
  5. ENERGY STAR, “Certified Air-Source Heat Pumps” dataset (w7cv-9xjt), records 2409880, 2409879, 2415664 and 2415663 (AHRI 204344218 to 204344221), read again on November 5, 2026.
  6. Hydro-Québec, “Heat pump search tool”, list of October 7, 2026 (LogisVert amounts).
  7. Hydro-Québec, LogisVert program, Participant’s guide for residential customers, version 1.10, September 15, 2026.

LogisVert amounts come from Hydro-Québec’s list on the date shown; only Hydro-Québec confirms the grant. AHRI numbers are those on our product pages, unchanged.