THERMO 2000 AltSource 50 Thermal Mass Electric Boiler | 24 kW - 240V
The 24 kW AltSource 50 is the highest-output AltSource 50: four 6 kW elements and 48 US gal of water, as the backup of a renewable heating system.
Model numberALTSOURCE50-24
514 316-2973 · sales@airgreen.ca
Quick facts
24 kW in the compact AltSource 50 format: the electric backup for high heating demands
The top of the AltSource 50 line
Thermo 2000’s AltSource 50 line runs from 4.5 to 24 kW, and this model sits at the top. It combines four 6 kW elements, controlled in four stages, with a 48 US gal tank, for 24 kW at 240 V, or 81,888 BTU/h. Like the rest of the series, it is a thermal mass electric boiler designed as the backup source of a renewable-energy heating system, which the manufacturer presents as the only high water volume electric boiler on the market.
The T2 UltraSmart controller and its outdoor sensor are supplied. They modulate output and water temperature to the weather, shut heating off in warm weather and offer a Boost mode. The controller runs in standalone electric mode by default or in automatic transfer on an external contact.
A decision that starts at the electrical panel
At 24 kW, electricity is not a detail. Thermo 2000 lists a current of 100 A at 240 V, a 125 A breaker and Cu 2 / Al 0 wire gauge. In a building with a 208 V supply, output becomes 18 kW at 87 A. Before recommending this size, we therefore do a full review of the electrical service and state clearly, in the quote, the work required.
When to choose the AltSource 50-24
This size suits very large homes and buildings with a high heating demand, in Montreal as on the North Shore, when geothermal, an air-to-water heat pump or solar does most of the work and a substantial backup is needed for the deep cold. Thermo 2000 offers the same output as an AltSource 70, with 71 US gal of water; the AltSource 50-24 keeps a more compact unit, 22 in in diameter, 25 1/2 in deep with the door and 56 7/16 in high, weighing 280 lb before filling. When the mechanical room is small, that often makes the difference.
On the loop, the unit connects in 1 in male NPT and operates at a maximum pressure of 30 psi. The manufacturer recommends a #30 expansion tank with baseboards or a radiant floor, and a #60 with cast-iron radiators.
Installation by AirGreen
After the free on-site estimate, the written quote details the boiler, circulator, expansion tank and electrical work. On installation day, our technicians set the AltSource in place, connect it to the loop and the circuit, mount the supplied outdoor sensor, relief valve and air vent, then fill, purge and set up the system with you.
Thermo 2000 covers the tank for 15 years in residential use and 10 years in commercial use, and the electrical and mechanical components for 2 years. AirGreen is a family business established in Montreal for more than fifteen years, holding RBQ licence 5645-9605-01 in ventilation, refrigeration and electrical work.
Ask for your quote
We serve Montreal, Laval, Longueuil, the North Shore and the South Shore. The estimate is free, the quote is in writing, and financing is available.
The strongest backup in the AltSource 50 line
The AltSource 50-24 is meant for buildings with a high heating demand that rely on an air-to-water heat pump, geothermal or solar for most of the work. It adds up to 24 kW in four stages, in the compact AltSource 50 format.
- Very large house heated by geothermal and a radiant floor
- Backup for an air-to-water heat pump where peak demand is high
- Mechanical room that cannot take a wider unit
- Project whose electrical service can carry a 100 A load
Specifications
From the manufacturer’s documentation. A value the manufacturer does not publish is not listed.
What to know before installing
- Thermo 2000 lists 100 A at 240 V, a 125 A breaker and Cu 2 / Al 0 wire gauge: the electrical service must be assessed before any commitment.
- At 208 V, output drops to 18 kW (87 A).
- The circulator and expansion tank are not on the list of supplied parts; recommended tank #30 for baseboards or a radiant floor, #60 for cast-iron radiators.
- Weight of 280 lb, plus the water in the tank once filled; 1 in male NPT fittings.
- Maximum working pressure of 30 psi (207 kPa).
- 30 psi (207 kPa) relief valve
- Drain valve
- Temperature and pressure gauge
- Automatic air vent
- Heating elements
- UltraSmart controller
- Outdoor sensor
Manufacturer documents
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Frequently asked questions
Is this the largest AltSource 50 model?
Yes. The AltSource 50 runs from 4.5 to 24 kW; above that, the series continues as the AltSource 70, up to 29 kW, with a 71 US gal tank.
What electrical load does it represent?
According to Thermo 2000, 100 A at 240 V, on a 125 A breaker with Cu 2 or Al 0 wire gauge. We do a full review of your electrical service during the free estimate.
What does it deliver at 208 V?
18 kW at 87 A, according to the manufacturer. We take this into account when choosing the size.
AltSource 50 or AltSource 70 at 24 kW?
The output is the same. The AltSource 50 keeps a 22 in diameter unit with 48 US gal of water; the AltSource 70 offers 71 US gal in a larger and heavier unit. The space available often tips the balance.
Which accessories are supplied?
The 30 psi relief valve, drain valve, temperature and pressure gauge, automatic air vent, heating elements, UltraSmart controller and outdoor sensor.
A 24 kW AltSource 50, installed by AirGreen
Tell us about your project: we check the sizing, confirm availability and send you a quote. Or let our technicians install it for you.
Specifications from the manufacturer’s documentation, checked on October 19, 2026.