THERMO 2000 AltSource 70 Thermal Mass Electric Boiler | 15 kW - 240V
The 15 kW AltSource 70 combines 71 US gal of water with four heating stages: a GHG-free electric backup for solar, geothermal or an air-to-water heat pump.
Model numberALTSOURCE70-15
514 316-2973 · sales@airgreen.ca
Quick facts
A GHG-free 15 kW backup with 71 US gal of water, to work alongside solar, geothermal or an air-to-water heat pump
A boiler designed as a complement
The AltSource can run on its own, but Thermo 2000 designs it first and foremost as the backup source of a renewable-energy heating system, and describes it as robust, low maintenance and running with no GHG emissions. The manufacturer also presents it as the only high water volume electric boiler on the market.
The 70-15 model combines the AltSource 70’s large 71 US gal tank with 15 kW at 240 V, or 51,180 BTU/h. This output is split between four elements, two of 3 kW and two of 4.5 kW, controlled in four stages.
Two ways to operate
The T2 UltraSmart controller offers two modes. In standalone electric mode, the default setting, the AltSource heats on its own. In automatic transfer mode, an external contact controls the unit, which lets it work with a main source. In both cases, the supplied outdoor sensor lets it modulate output and water temperature to the weather; in mild weather, it shuts heating off, and a Boost mode is available.
A typical North Shore project
Take a North Shore home with solar thermal collectors and an air-to-water heat pump, a radiant floor in the basement and hot-water baseboards upstairs. The AltSource 70-15 goes in the mechanical room and adds heat when the sun and the heat pump fall short. Water can be heated from 50 °F to 190 °F (10 °C to 88 °C).
Before the work, space and electricity must be planned. The unit measures 24 in in diameter and 28 in deep with the door, and weighs 380 lb before filling. Thermo 2000 lists an 80 A breaker and Cu 6 / Al 4 wire gauge at 240 V; at 208 V, output becomes 11.2 kW at 54.3 A. The loop connects in 1 1/4 in NPT and operates at 30 psi maximum, with a #60 expansion tank recommended for baseboards or a radiant floor, or a #90 for cast-iron radiators.
Our installation
We start with a free on-site estimate, then give you a written quote that specifies the boiler, circulator, expansion tank and electrical work. Our technicians install the AltSource, connect it to the loop and the circuit, mount the outdoor sensor and supplied accessories, then fill, purge and set the operating mode. Thermo 2000 covers the tank for 15 years in residential 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.
Your free estimate
We serve Montreal, Laval, Longueuil, the North Shore and the South Shore. Ask for your estimate: the quote is in writing and financing is available.
The electric backup of a renewable system
The AltSource 70-15 keeps 71 US gal of water in its tank and adds up to 15 kW in four stages. Its controller runs on its own, in standalone electric mode, or in automatic transfer on an external contact.
- Home with solar thermal collectors and an air-to-water heat pump
- Backup for a geothermal system in a large house
- Radiant floor and hot-water baseboards supplied by the same loop
- Project that calls for a low-maintenance unit
Specifications
From the manufacturer’s documentation. A value the manufacturer does not publish is not listed.
What to know before installing
- 240 V single-phase circuit with an 80 A breaker and Cu 6 / Al 4 wire gauge, according to Thermo 2000; at 208 V, output drops to 11.2 kW (54.3 A).
- Unit of 380 lb before filling, 24 in in diameter and 28 in deep with the door: access to the mechanical room is checked at the estimate.
- Recommended expansion tank: #60 for baseboards or a radiant floor, #90 for cast-iron radiators. It is not among the supplied parts, nor is the circulator.
- 1 1/4 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
Explore the range
Electric boilersSee allSame brand
THERMO 2000See all
Frequently asked questions
What are the two operating modes?
Standalone electric mode, the default, where the AltSource heats on its own, and automatic transfer mode, controlled by an external contact (E1-E2). We choose the mode based on how your main source is connected.
Does the AltSource need much maintenance?
Thermo 2000 describes it as robust and low maintenance. At commissioning, we show you the temperature and pressure gauge and the controller settings so you can keep an eye on the system.
What breaker is needed?
An 80 A breaker and Cu 6 or Al 4 wire gauge, at 240 V single phase. At 208 V, output becomes 11.2 kW at 54.3 A.
Can it preheat domestic water?
Yes, with the heat exchanger Thermo 2000 offers as an option: 26.2 sq ft parallel copper coils, 12 gpm maximum flow, 125 psi maximum pressure.
What warranty does Thermo 2000 offer?
15 years on the tank and coils in residential use, 10 years in commercial use, and 2 years on electrical and mechanical components and accessories.
A 15 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.