THERMO 2000 AltSource 70 Thermal Mass Electric Boiler | 29 kW - 240V
The 29 kW AltSource 70, top of Thermo 2000’s AltSource range: a 71 US gal thermal mass electric boiler that backs up a renewable heat source.
Model numberALTSOURCE70-29
514 316-2973 · sales@airgreen.ca
Quick facts
The top of the AltSource range: 29 kW of electric backup paired with 71 gallons of hot water
What the 29 kW AltSource 70 is
Thermo 2000 lists its AltSource range from 4.5 to 29 kW, and this model sits at the top. At 240 V, it delivers 98,948 BTU/h through six heating elements, four at 5 kW and two at 4.5 kW, controlled over six stages. Like every AltSource, it is a thermal mass electric boiler: the 70 version keeps 71 US gallons of water in its tank and backs up a renewable-energy heating system.
It is aimed at hot-water-heated buildings whose load justifies the largest size in the series, whether a large house or a small building. Thermo 2000 covers the tank and coils for 15 years in residential use and 10 years in commercial use, and electrical and mechanical components for 2 years.
What this size requires electrically
A 29 kW boiler is planned at the panel first. At 240 V single phase, the unit draws 120 A and Thermo 2000 lists a 175 A breaker, with copper wire gauge 1 or aluminum gauge 00. If the building is supplied at 208 V, the boiler delivers 21.8 kW at 104 A. These figures guide the choice: in some cases, a smaller size in the series is a better fit for the existing electrical service.
How it works with your main source
The sun does not heat the house in the middle of a February night, and an air-to-water heat pump loses ground as the cold deepens. The AltSource fills those gaps. The supplied outdoor sensor lets the T2 UltraSmart controller modulate output and water temperature based on the outdoor temperature; warm weather shutdown and Boost mode round out the settings. And if the renewable source is not in place yet, standalone electric mode, the default setting, lets the boiler heat on its own.
The boiler serves radiant floors, hot water baseboards and radiators, between 50 °F and 190 °F. As an option, a copper coil heat exchanger heats or preheats domestic water.
What AirGreen’s installation covers
We start with a free on-site estimate, paying close attention to the electrical service and the floor location: the unit is 24 in in diameter and weighs 380 lb. You receive a clear written quote. Our technicians then install the boiler, make the electrical and hydronic connections, fill and purge the loop, then set the controller for your main source.
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.
Let’s talk about your project
We carry out these installations in Montreal, Laval and Longueuil, as well as on the North Shore and the South Shore.
Ask for your free estimate: we validate the size against your electrical service and give you a written quote. Financing is available.
The largest size in the AltSource range
Thermo 2000 lists the AltSource from 4.5 to 29 kW; this model sits at the top. It backs up an air-to-water heat pump, a solar system or geothermal, and can also heat on its own in standalone electric mode.
- Supplementing a solar thermal system on sunless days
- Backing up an air-to-water heat pump during extreme cold
- Backup for a geothermal system
- Hot-water-heated buildings whose load calls for the top of the AltSource range
- Heating or preheating domestic water with the optional coil heat exchanger
Specifications
From the manufacturer’s documentation. A value the manufacturer does not publish is not listed.
What to know before installing
- At 240 V single phase, the unit draws 120 A and requires a 175 A breaker; suggested wire gauge: copper 1 or aluminum 00. Have your electrical service checked before choosing this size.
- At 208 V, Thermo 2000 lists 21.8 kW and 104 A.
- Floor-standing unit: 24 in diameter, 28 in deep with the door, 380 lb.
- Maximum working pressure of 30 psi (207 kPa); temperature range of 50 °F to 190 °F.
- Recommended expansion tank: #60 for baseboards or radiant floors, #90 for cast iron radiators. Required clearances are listed in the installation manual.
- 30 psi (207 kPa) relief valve
- Drain valve
- Temperature and pressure gauge
- Automatic air vent
- Heating elements (4 x 5 kW + 2 x 4.5 kW)
- UltraSmart controller
- Outdoor sensor
Manufacturer documents
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Frequently asked questions
What electrical service does 29 kW require?
At 240 V, the unit draws 120 A and Thermo 2000 lists a 175 A breaker, with copper wire gauge 1 or aluminum gauge 00. We check your electrical service during the free estimate, before confirming this size.
What if the building is supplied at 208 V?
Thermo 2000 then lists an output of 21.8 kW and a current of 104 A.
Can the boiler back up a solar system?
Yes. Thermo 2000 names solar among the main sources the AltSource supplements, along with air-to-water heat pumps and geothermal.
Which standards does the boiler meet?
Thermo 2000 lists CSA C22.2 No. 165-92 in Canada and UL 834 in the United States.
How hot does it heat the water?
The operating range is 50 °F to 190 °F (10 °C to 88 °C), with a maximum working pressure of 30 psi (207 kPa).
A 29 kW AltSource 70, 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.