An island fortified since 1759, and a rule that does not say where to place the outdoor unit—it says what is no longer allowed in the basement.
About fifteen kilometres from the U.S. border, the Richelieu River widens around a 1.5-kilometre island that Champlain described in 1609 as a land “remply de forests, vignes & noyers.” Île aux Noix was fortified as early as 1759 by Colonel Bourlamaque, captured by the British on August 28, 1760 after a twelve-day siege, occupied by the Americans in 1775–1776, and then equipped between 1819 and 1829 with the stone fort visited today—the Fort Lennox, designated a national historic site on January 30, 1920, and occupied by a garrison until 1870. A shipyard there built warships during the War of 1812 before closing in 1834.
One detail that even local residents confuse: the Rivière-Lacolle Blockhouse, designated a heritage building on November 16, 1960, bears the name of another municipality but is indeed located in Saint-Paul-de-l'Île-aux-Noix.
That sets the stage. What concerns us here is more prosaic and much more useful to the homeowner: in this municipality, the most consequential regulation for a heating system does not concern the outdoor unit. It concerns what may legally be installed in the basement.
This is a nuance that almost nobody publishes, and it changes the comparison between heating technologies across much of the region.
What was installed
| Item | Data |
|---|---|
| Outdoor unit | GREE FreeMatch R32 GWHD(36)ND6MO |
| Nominal capacity | 10,550 W — 36,000 BTU/h, for both cooling and heating |
| Heads | 24,000 (open area) + 12,000 (primary bedroom) = 36,000 BTU/h, or 100% of nominal capacity |
| Modulation range (heating) | 2,600 to 15,000 W — 8,870 to 51,180 BTU/h |
| Dimensions | SEER2 21 · HSPF2 10 · EER2 12 · COP 3.56 |
| AHRI reference | 214931589 |
| Heating range | −30 °C to 24 °C |
| Factory charge | 2,700 g of R32 |
| Piping | 8 m + 15 m = 23 m developed length, well below the 40 m precharge → no R32 added |
| Electrical | MCA 30 A · MOCP 45 A |
| Cabinet | 1,020 × 826 × 427 mm, 78.5 kg, 3,413 cfm, 63 dB(A) |
Values taken directly from the manufacturer's X610068B data sheet. Two remarks on the choice of capacities. The 12,000 head rather than a 9,000 one is due to the margin above the 8,870 BTU/h modulation floor: the complete arithmetic reasoning was published on our Noyan page, and we apply it here without repeating it. And since the 23 metres remain well below the precharge limit, no refrigerant top-up was required—the A2L minimum-area verification therefore used the unchanged factory charge of 2,700 g.
The 36,000 chassis accepts up to four indoor units. Two ports remain free, subject to the reservations we have already published elsewhere regarding the actual value of an available port.
The rule no one cites: what can no longer be installed in a basement
Let's start with the text, because that is what does the work.
The provincial framework applicable to flood zones—the Regulation respecting activities in wetlands, bodies of water and sensitive areas, in section 38.6—sets out, among the flood-proofing measures:
“An important component of a building mechanical system, such as an electrical system, plumbing system, heating system, or ventilation system, may not be installed in a basement unless, by its nature, it must necessarily be located there.”
Read it twice. It says nothing about a heat pump, furnace, or brand. It refers to a heating system and where it is located in the building.
Why this matters more here than elsewhere
Saint-Paul-de-l'Île-aux-Noix is a riverfront municipality, a significant portion of whose territory is subject to floodplain regulations. Its Zoning By-law 231-2006 devotes an entire chapter—Chapter 12, on environmental protection—to this subject, using the classic two-tier framework: 0–20-year flood recurrence zone and 20–100-year flood recurrence zone, each with its own list of permitted work, variance conditions, and acceptability criteria. This chapter even contains an article specific to the municipality concerning the variances it has obtained.
The Building By-law 233-2006 adds the building's own flood-proofing measures. What we were able to read is clear: no opening—window, basement window, access door, or garage—may be reached by the 100-year flood, nor may any ground-floor level; drainage must be equipped with backwater valves; any structure below the flood level requires an engineer's study; and fill slopes must have a slope of at least 33 ⅓%.
One verified finding deserves to be stated as is: this building regulation contains no provision requiring exterior mechanical equipment to be raised above a flood level. The municipal requirement concerns openings, floors, drainage, and fill. It is the provincial text cited above that addresses building mechanical components, and it addresses the basement.
What this changes when choosing a system
Here is the consequence, and we state it cautiously because it falls under the authority of the competent body, not us.
A conventional central heating system — furnace, air handler, and tank — traditionally occupies the basement. On a lot where the flood-proofing regime applies, this traditional location becomes precisely the one targeted by the rule. A ductless system addresses the question differently: the indoor heat exchanger is a wall-mounted unit installed high in the room it serves, often on the occupied floor, with no furnace, cabinet, or plenum below.
This is not a sales argument; it is an observation about the geometry of the problem. It does not exempt anyone from anything: the electrical circuit, disconnect switch, outdoor unit, and penetrations still have to be addressed according to the same rules as everywhere else. And regarding this exterior aspect, we are adding nothing to what we have already published: the flood elevation and the position of the disconnect switch are covered on our Ormstown page, the elevation reference that belongs to the building and not to the municipality on the Sainte-Marthe-sur-le-Lac page, and the water-season protocol on the Sainte-Anne-de-Sorel page. We refer you to those pages rather than rewriting the information here.
Only one line deserves to be repeated, because it is the source of half the misunderstandings: an installation elevation belongs to the building and the lot, never to a municipality as a whole. Two houses on the same street do not necessarily have the same answer.
New rules on old maps: the particular situation of Haut-Richelieu in 2026
The second point is a matter of timing, and it is current as of the time of writing.
Quebec’s flood zone regime has been modernized. The transitional regime has ended, and the new framework has applied since March 2026. At the same time, the government is gradually publishing new mapping.
Except that the Haut-Richelieu RCM does not yet have one. The RCM’s general management stated publicly in September 2025 that new flood-zone mapping was not expected before 2027 in its territory, and that it did not know which data the ministry would use. The applicable principle is clear: in the absence of next-generation mapping, the maps currently in force remain those held by the municipality and the RCM.
For a property owner here, this can be summed up in one sentence: the rules have changed, but the map has not. This is exactly the context in which one does not guess but asks.
Let us also recall that the area was covered by special intervention zones decreed after the 2011 and 2019 floods, the latter concerning the 0–20-year flood zone. We mention these decrees because they explain the current regulatory framework, and we stop there: whether a specific lot is covered is a question to ask the municipality, with the lot details in hand.
The permit: here, the appliance is named
Good news for once, and it has been verified. The Permits and Certificates Regulation 234-2006 lists, among the work requiring an authorization certificate, the explicit wording: “heat pump and other similar appliance”. The applicable category is the certificate for construction or accessory equipment, and a separate provision concerns works on the shore or shoreline.
The Zoning Regulation 231-2006 also has a section dedicated to this equipment in its chapter on residential uses—two provisions, one entitled General Provisions and the other Siting, covering heat pumps, water heaters, pool filters, and similar appliances—as well as a corresponding section for commercial uses.
We were unable to read the text: the document cuts off before those pages. We therefore will publish no setback, no prescribed yard, no screening requirement, and no height. We even point out that a footnote reference accompanies the mention of “heat pump” in the permits regulation, and that we were unable to read that note—this is precisely the kind of detail that changes an answer.
Regarding noise, the Noise Nuisance Regulation 473-2026, adopted on June 3, 2026, sets no decibel threshold and mentions neither heat pumps nor mechanical equipment; it prohibits the use of an appliance causing excessive noise between 11 p.m. and 7 a.m. We cite it for what it is, without drawing any acoustic argument from it—the subject is addressed elsewhere on our pages.
Finally, no PIIA bylaw appears in the planning documentation published by the municipality. We present this as a reading-based observation, not as certainty: it is something to confirm with the inspector.
Our position does not change from one municipality to another: we cite a regulation; we do not interpret it. The complete method—the list of questions to ask before ordering the equipment—was published on our Saint-Mathias-sur-Richelieu and Mont-Saint-Grégoire pages; we apply it here without rewriting it. Remember the mechanics: request the certificate first, then set the installation date. Never the other way around.
The indoor unit, in three lines
We will be brief about the installation itself, because the essentials have already been written and readers deserve better than a repetition. The wall-mounted head was installed according to the criteria we apply everywhere: a clear section of wall and the manual's required clearances maintained above and on the sides, the mounting plate anchored into solid wood, a continuous downward slope for the condensate drain verified before the plate was mounted—the criterion that eliminates the greatest number of “ideal” positions—the airflow axis following the length of the room, and a filter accessible without a stepladder. Our LaSalle, Saint-Polycarpe, and Les Cèdres pages expand on each of these points.
And one thing we systematically check when a head is installed near a fitted ceiling: an airflow sweeping across a smoke detector is not a minor detail. The mechanism, the rule—we move the detector, not the head—and the check at recommissioning are published on our Montréal-Nord page.
The difference from our other Haut-Richelieu pages
We recently documented Mont-Saint-Grégoire, where the question was: what does the regulation say, and where is the unit allowed to be installed? And Noyan, where it was: where does the unit come from, and who is authorized to work on it?
Here, the question is different again: it is not where to install it, but what is no longer allowed downstairs. Floodplain regulations do not address aesthetics or setbacks: they designate a floor.
At AirGreen, we install, maintain, and document HVAC systems in Saint-Paul-de-l'Île-aux-Noix, Noyan, Mont-Saint-Grégoire, Saint-Bernard-de-Lacolle, and throughout Haut-Richelieu, as well as in Montréal, Laval, Longueuil, on the North Shore, and on the South Shore. If your property borders a river, shoreline, or flood zone, tell us at the first visit: that is when it costs the least to address.