Installation of a Midea28 wall-mounted heat pump on a flat roof in southwest Montreal
AirGreen installs a Midea28 wall-mounted heat pump on a flat roof in southwest Montreal: performance down to -30°C, energy savings and durability for optimal comfort all year round.
In summer, the outdoor unit rejects the house's heat outside.
Generic illustration of this type of installation, not a survey of this job site. Tap a number.
Mounted level on a wall plate, high enough for the air to reach the whole room, with enough space around it to slide the filters out easily.
The refrigerant lines, the communication cable and the drain go through the wall in a single opening, sealed against water, cold air and insects.
Two insulated copper pipes connect the two units. Outside, a line cover can protect them from sun, knocks and weather.
A shut-off switch near the outdoor unit isolates it safely for service. It must stay accessible at all times.
The compressor and the fan. In heating mode it captures heat from the outdoor air, even in winter, and moves it inside.
On the ground or on the wall, it keeps the unit above accumulated snow. The unit stays clear and defrost water can drain away.
The fan needs to blow freely. Storage, a fence or a wall too close, and efficiency drops while noise goes up.
A custom installation for a Montreal condo exposed to the harshness of winter
At AirGreen , we recently completed a Midea28 wall-mounted heat pump installation on the flat roof of a residential building in Southwest Montreal . This project perfectly illustrates our expertise in urban environments where floor space is limited and where every technical detail counts to guarantee the energy performance , safety and sustainability of the installation.
A typical Montreal challenge: installing on a flat roof
Installing a heat pump on a flat roof requires careful planning. In Montreal, where winters can be harsh and precipitation abundant, it is essential to ensure that the outdoor unit is perfectly stabilized and protected against water, snow, and ice .
In this project, our team opted for a raised aluminum structure , fixed on treated wood shoes , with rigid foam insulation under the crosspieces in order to preserve the integrity of the roof membrane . This assembly allows:
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Optimal air circulation around the condenser.
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Efficient evacuation of meltwater during the thawing period.
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Increased protection against vibrations and freezing.
The result: an installation that is robust, aesthetically pleasing and complies with Montreal building safety standards .
Model choice: the Midea28, an R-454B extreme cold heat pump
The Midea28 is one of the new generations of wall-mounted heat pumps using R-454B refrigerant , a fluid with low global warming potential (GWP reduced by 78% compared to R-410A).
This model offers several essential advantages for the Quebec climate:
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Performance down to -30°C , ideal for our Montreal winters.
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High energy efficiency (SEER greater than 21 / HSPF 12.5) .
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Inverter technology allowing precise power adjustments.
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Quiet operation – a plus for high-density buildings.
By choosing the Midea28, the customer will benefit from stable comfort year-round and a significant reduction in energy costs , while taking advantage of available subsidies offered by the Chauffez vert program and Hydro-Québec incentives for energy-efficient systems.
Technical details of the installation
Our team coordinated the installation in a single day, despite the cold weather conditions of early March. Here are the main steps completed:
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Preliminary inspection of the roof to confirm the strength and watertightness of the membrane.
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Installation of the raised support with laser calibration for perfect leveling.
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Install high-density foam insulation under the sleepers to prevent abrasion.
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Midea28 outdoor unit installation , optimized orientation for airflow and maintenance.
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Refrigerant connection with full thermal insulation and white cover for a discreet finish.
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Dedicated electrical connection , compliant with the requirements of the Régie du bâtiment du Québec (RBQ) .
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Operation test in heating mode , checking pressure, defrosting and drainage.
The heat pump was commissioned with a complete performance check: airflow, intensity, superheating and subcooling. All validated by our certified AirGreen technician , holder of a CCQ license .
Discreet and lasting integration
On this flat roof, the Midea28 blends harmoniously into the surroundings. The white-coated pipes and anodized aluminum metal fittings not only ensure an aesthetic appearance, but also excellent corrosion resistance .
Access is facilitated for seasonal maintenance, and the safety distance from the guardrail complies with the recommendations of the Quebec Construction Code .
Maintenance and prevention
We recommend that the client have an annual maintenance including:
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Checking the automatic defrost.
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Cleaning the outdoor coil.
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Checking refrigerant insulation and refrigerant pressure.
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Inspection of the support and fixings after the winter season.
At AirGreen, we offer a preventative maintenance program specifically designed for flat roof installations, ensuring optimal performance and increased system longevity.
Result: comfort, reliability and peace of mind
Thanks to this Midea28 heat pump installation on a flat roof, the condo owner now benefits from:
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Reliable heating down to −30°C .
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Effective cooling in summer .
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An energy-efficient system that reduces your annual electricity bill.
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A compliant, clean installation designed to last.
This achievement once again demonstrates AirGreen's ability to adapt to all residential configurations in Montreal, whether it is a duplex in the Plateau, a building in the Southwest or a new condo in Griffintown.
Your project, our expertise
Do you live in a condo in Montreal, Laval or on the South Shore and want to install a Midea28 heat pump or another model from the Midea, Gree or Fujitsu range?
At AirGreen, we take care of every step: space analysis, selection of the right model, certified installation and maintenance follow-up .
Trust a local team that understands the climate and regulatory realities of Greater Montreal and is committed to delivering sustainable, efficient, and impeccable facilities.
AirGreen — Heat Pumps, Air Conditioning & Heating.
Your comfort, our mission.
How it goes, from the first call to the end
The main steps of this kind of job at AirGreen. Every house has its quirks: the estimate brings them out.
We look at the room, the outside wall, the line route and where the outdoor unit will go. That is where the capacity gets chosen.
Model, capacity and price, in writing. We also check whether the model qualifies for assistance programs.
Floors and furniture protected, wall plate position marked level, wall opening located.
A single opening, with the slope the drain needs to flow outside.
Set on a stand raised above the snow, with the clearances the manufacturer requires.
Connected, insulated and protected. The opening is then sealed against water, cold air and insects.
A dedicated circuit and an accessible disconnect near the outdoor unit.
Leak test, vacuum, then start-up and a check of heating and cooling.
Remote, modes, filters: we show you the essentials before we leave.
- The on-site estimateWe look at the room, the outside wall, the line route and where the outdoor unit will go. That is where the capacity gets chosen.
- The quoteModel, capacity and price, in writing. We also check whether the model qualifies for assistance programs.
- Getting readyFloors and furniture protected, wall plate position marked level, wall opening located.
- The wall openingA single opening, with the slope the drain needs to flow outside.
- The outdoor unitSet on a stand raised above the snow, with the clearances the manufacturer requires.
- Lines, cable and drainConnected, insulated and protected. The opening is then sealed against water, cold air and insects.
- The electrical workA dedicated circuit and an accessible disconnect near the outdoor unit.
- Tests and start-upLeak test, vacuum, then start-up and a check of heating and cooling.
- The walkthroughRemote, modes, filters: we show you the essentials before we leave.
What the unit delivers when it is cold
The range as published on airgreen.ca: pick a size to see its capacity in deep cold.
| Size | Heating at −8 °C | Heating at −15 °C | Coldest certified point | COP at −15 °C | SEER | HSPF | Indicative LogisVert aid |
|---|---|---|---|---|---|---|---|
| Midea Série 28 9 000 | 12,000 | 11,500 | −30 °C: 5,100 | 1.8 | 27.4 | 12.5 | – |
| Midea Série 28 12 000 | 12,000 | 11,500 | −30 °C: 5,900 | 1.8 | 25.4 | 10.5 | $1,440 |
| Midea Série 28 18 000 | 18,000 | 18,000 | −30 °C: 8,000 | 1.92 | 21.4 | 11.0 | $2,160 |
| Midea Série 28 24 000 | 22,200 | 24,200 | −30 °C: 11,900 | 2.34 | 21.0 | 13.5 | $2,664 |
| Midea Série 28 33 000 | 32,000 | 35,000 | −30 °C: 20,700 | 1.98 | 19.5 | 10.5 | $3,840 |
According to NEEP, it delivers 12,000 BTU/h at −8 °C (17 °F), as much as at 8 °C. It heats as hard in moderate cold as in mild weather.
At 8 °C, its certified maximum capacity reaches 16,000 BTU/h, 78% more than its nominal 9,000 BTU size.
According to NEEP, its certified heating capacity at −15 °C (5 °F) is 11,500 BTU/h, 128% of its nominal 9,000 BTU size. Its COP there is 1.80.
According to NEEP, it delivers 12,000 BTU/h at −8 °C (17 °F), as much as at 8 °C. It heats as hard in moderate cold as in mild weather.
At 8 °C, its certified maximum capacity reaches 16,000 BTU/h, 33% more than its nominal 12,000 BTU size.
At −30 °C, its certified minimum capacity is 2,000 BTU/h (3,800 at 8 °C). It slows down instead of cycling on and off.
According to NEEP, it delivers 18,000 BTU/h at −8 °C (17 °F), as much as at 8 °C. It heats as hard in moderate cold as in mild weather.
According to NEEP, its certified heating capacity at −15 °C (5 °F) is 18,000 BTU/h, 100% of its nominal 18,000 BTU size. Its COP there is 1.92.
According to NEEP, its COP at −15 °C is 2.34: the highest of the Série 28 line, which ranges from 1.80 to 1.98 at that temperature.
At −30 °C, its certified minimum capacity is 2,400 BTU/h (11,800 at 8 °C). It slows down instead of cycling on and off.
According to NEEP, its certified heating capacity at −15 °C (5 °F) is 24,200 BTU/h, 101% of its nominal 24,000 BTU size. Its COP there is 2.34.
According to NEEP, its certified maximum capacity at −30 °C (−22 °F) is 20,700 BTU/h, 63% of its nominal 33,000 BTU size.
At −30 °C, its certified minimum capacity is 4,200 BTU/h (19,700 at 8 °C). It slows down instead of cycling on and off.
According to NEEP, its certified heating capacity at −15 °C (5 °F) is 35,000 BTU/h, 106% of its nominal 33,000 BTU size. Its COP there is 1.98.
Data read live from the airgreen.ca page of each size (NEEP / AHRI certified performance). When the title names the installed size, it is highlighted; otherwise the whole range is shown. The aid shown is today’s, using Hydro-Québec’s rule ($120 per 1,000 BTU/h at −8 °C); amounts quoted in the article date from its publication. Only Hydro-Québec confirms the assistance granted.A dash in the aid column: amount to be confirmed for this model.
And at your place?
Two quick checks with real numbers: what heat costs, and what your current heaters add up to in BTU/h.
Baseboards and electric furnaces turn 1 kWh of electricity into 1 kWh of heat. A heat pump delivers more: that is its COP. At Hydro-Québec’s rate D (11.142¢/kWh above 40 kWh a day, since 1 April 2026):
Hydro-Québec: a heat pump can be up to three times more efficient than baseboards for heating in the colder months.
Estimate per kWh of heat, at the chosen temperature, using the certified COP from the product page. Taxes, access charge and backup heat not included.
Conversion: 1 W = 3.412 BTU/h. An indication, not a load calculation: baseboards and furnaces are often stronger than the real need, and they can stay as backup. AirGreen confirms the capacity on site.
What to do, season by season
Three habits per season for this unit. They take a few minutes and prevent many calls.
- Clean the indoor unit's filters.
- Clear leaves and debris left on the outdoor unit by winter.
- Test cooling before the first hot days.
- Clean the filters more often when the unit runs a lot.
- Keep plants away from the outdoor unit.
- Check that no water drips from the indoor unit.
- Rake the leaves around the outdoor unit.
- Test heating before the first cold days.
- Book periodic maintenance before winter.
- Keep snow away from the stand and the front of the unit.
- Let the unit defrost: it is normal.
- Never hit the ice on the fins; call us if the unit stays iced up.
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What people ask us about this kind of work
Does a wall-mounted heat pump heat in winter?
Wall-mounted or multi-zone: how do I choose?
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The outdoor unit is covered in ice: is that normal?
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Text and photo: a real AirGreen Climatisation & Chauffage job. The diagrams are generic illustrations of the type of installation, not a survey of this job site. Sources of the added figures: airgreen.ca product pages (NEEP / AHRI performance), Hydro-Québec (Heat pumps page, LogisVert, read on 13 October 2026), Régie de l’énergie (rate D as of 1 April 2026).