Electronic Thermostat STELPRO ST402P 4000 W | Montreal, Laval, Longueuil, South Shore and North Shore

The more energy a room uses, the more good programming pays off. An open-concept living room heated by several baseboard heaters, a finished basement or a large family room can, on its own, account for a big share of a home's heating consumption. That's the kind of space where the Stelpro ST402P really makes sense. This programmable electronic thermostat controls up to 4000 W at 240 V of electric baseboard heaters or convectors, and automatically lowers the temperature when the room isn't in use. At AirGreen, we install it in living spaces where people want the savings to happen on their own.

Programming where it matters most

In a large room, the heat is often left at the same level from morning to night, even when everyone is at work or at school. The ST402P changes that habit with no effort: it follows a schedule of 4 periods on weekdays and 2 periods on weekends. The room warms up before you get up, the temperature drops during the day, rises again for the evening, then drops again at night. According to Stelpro, this type of programming can bring up to 20% in energy savings. On a 4000 W load, you notice the effect.

Three-step programming

What many homeowners dread is complexity. Stelpro's answer is three-step programming, designed to be understood quickly. Our technicians set it up with you during installation, and you come away knowing how to change it.

A capacity suited to open spaces

The ST402P runs on 120, 208 or 240 V, with a load range of 150 to 2000 W at 120 V, 260 to 3475 W at 208 V and 300 to 4000 W at 240 V. That margin lets it control several baseboard heaters on one circuit, a common situation in open-concept rooms and basements. For a bedroom or an office, the 3000 W version, the ST302P, offers the same programming features.

Precision and protection

Thermistor-based control holds the temperature within ±0.5 °C (1 °F), over a set point range of 5 to 30 °C (41 to 86 °F). The digital display works in °C or °F. If the power goes out, the programming is kept for 2 hours, so you don't have to reprogram everything after a short outage.

A solid mount

It connects with 2 wires, and the S3 mounting plate gives a stable, safe mount. The white moulded plastic casing stays discreet, and the thermostat is certified to CSA C828-19.

Programmable or non-programmable

The ST402P has a non-programmable sibling, the ST402NP, which relies on an ECO mode you turn on by hand. For a living space used at set times, the ST402P's programming is more effective, since it never forgets to lower the temperature. For a room with irregular use, the ST402NP may be enough. And if the room is heated by a fan heater, the ST402PFF offers the same programming with a connection designed for fan units.

Technical specifications

• Type: programmable electronic line-voltage thermostat
• Systems: electric baseboard heaters and convectors (2-wire)
• Voltage: 120/208/240 V
• Load range: 150 to 2000 W at 120 V; 260 to 3475 W at 208 V; 300 to 4000 W at 240 V (max. 4000 W at 240 V)
• Programming: up to 4 periods on weekdays and 2 on weekends; three-step programming
• Protection: settings kept during a power outage (2 hours)
• Accuracy: ±0.5 °C (1 °F), thermistor sensing
• Set point: 5 to 30 °C (41 to 86 °F)
• Display: digital, °C or °F (selectable)
• Connection: 2-wire; S3 mounting plate
• Savings: up to 20% according to Stelpro
• Certification: CSA C828-19
• Colour: white, moulded plastic

Installation by AirGreen and recommended settings

Before installation, our qualified technicians add up the wattage of the baseboard heaters connected to the thermostat. It's an important step in large rooms, where we sometimes find that an old thermostat was controlling more baseboards than expected. Once the load is confirmed, the circuit is shut off at the panel, the S3 plate is mounted, the thermostat is connected with two wires, then the power is restored. We set the time, the day and a first schedule with you.

If you're replacing the thermostats throughout the house, we assign each room the Stelpro model whose capacity matches its load, for a compliant installation and a consistent look.

A typical schedule for a large room

For a living room or a family room, an efficient schedule brings the temperature up about half an hour before wake-up, sets a moderate setback while you're out, returns to comfort before supper, then drops at bedtime. On weekends, two periods are enough: comfort during the day, a setback at night. In a large room, avoid deep setbacks: warming back up would take a long time, especially in the deep cold of January and February.

Pairing it with a heat pump

In large open spaces, many of our clients add a wall-mounted heat pump to cut down on how much the baseboards have to do. The ST402P fits well with this approach: set a little lower than the heat pump, it provides backup heat during cold snaps, while the heat pump does most of the work. We can advise you on this combination.

Maintenance

Dust the thermostat and the baseboard heaters every fall. Don't put furniture in front of the baseboards. Check the time after a long outage so the schedule stays accurate, and review your programming whenever the season or your family's routine changes.

Why AirGreen

AirGreen is a family-owned HVAC company that holds an RBQ licence, with more than 15 years of experience and a showroom in Boucherville. To buy the Stelpro ST402P programmable thermostat and have it professionally installed, contact us. We serve Montreal, Laval, Longueuil, the North Shore and the South Shore.

Stelpro documents

Stelpro spec sheet (PDF) · Stelpro user guide (PDF)