Stelpro Ki Thermostat – Electric Baseboard

The Stelpro Ki STZW402 was one of the best Z-Wave thermostats available for properties with electric baseboard heat.

Unfortunately, Stelpro has now discontinued it.

That’s particularly disappointing for us because we’ve managed a property with 12 Stelpro Ki thermostats installed throughout the home for years, and they have been almost exactly what we want from rental automation equipment:

They stay online.

They respond reliably.

They’re easy to manage through SmartThings.

Guests understand how to adjust them.

And after years of real-world use, they’ve required remarkably little attention.

So our conclusion today is a little unusual.

If you already have Stelpro Ki thermostats installed, we would absolutely keep using them.

But because the STZW402 is discontinued, we would not build a new multi-zone heating system around them today.

The thermostat itself is still excellent.

The problem is product availability and long-term replacement support.

The Stelpro Ki Has Been Discontinued

Stelpro now officially lists the STZW402+ Z-Wave thermostat as a discontinued product.

The Zigbee version of the Ki has also been discontinued, along with Stelpro’s Maestro and Allia connected thermostat systems.

That changes how we evaluate the product.

When we originally installed these thermostats, the Stelpro Ki was a very attractive option for anyone who wanted to control line-voltage electric heat through a Z-Wave smart-home platform.

Today, we wouldn’t recommend purchasing a dozen discontinued thermostats and building a new property automation system around them.

Replacement availability matters.

If one of our existing 12 thermostats eventually fails, we want to know that we can replace it without redesigning the heating-control system.

That’s much harder to guarantee once a product has left production.

Discontinued Doesn’t Mean Bad

There’s an important distinction here.

We are not removing the Stelpro Ki from consideration because it performed poorly.

Quite the opposite.

Our experience has been excellent.

This is very different from a product that loses our recommendation because long-term testing uncovers reliability problems.

The Stelpro Ki has been one of the more dependable smart thermostats we’ve operated.

Its only major problem today is that Stelpro no longer makes it.

If you already have one—or an entire property full of them—we don’t see any reason to replace functioning thermostats simply because the model has been discontinued.

Our Experience With 12 Heating Zones

Our strongest evidence for the Stelpro Ki comes from managing a property with 12 separate heating zones.

Each zone uses its own Stelpro Ki thermostat to control electric heat.

That’s a meaningful test.

A single thermostat can look reliable when you’re only operating one device.

With 12 thermostats spread throughout a property, any connectivity or hardware weakness becomes much more obvious.

If they disconnected regularly, missed commands, needed frequent resets, or confused guests, managing the system would become painful very quickly.

That hasn’t happened.

Over years of use, the thermostats have been remarkably dependable.

They connect through Z-Wave, remain available in SmartThings, respond predictably to automation commands, and continue functioning locally for guests.

That’s exactly what we want from rental-property hardware.

Designed Specifically for Electric Baseboard Heat

The Stelpro Ki is a line-voltage thermostat.

That distinction is extremely important.

It is not interchangeable with a normal 24V thermostat such as an ecobee, Nest, or typical Honeywell central-HVAC thermostat.

The STZW402 directly controls electric resistance heating and supports:

• Electric baseboard heaters
• Electric convectors
• 120V systems
• 240V systems

Stelpro rates the thermostat for loads up to 2,000 watts at 120V or 4,000 watts at 240V.

That makes it useful for a relatively specific type of property.

If your rental has a furnace, central air conditioner, or conventional heat pump controlled by low-voltage thermostat wiring, this isn’t the right device.

The Downside of 12 Zones: Cost

The downside is obvious once you start multiplying the price of the thermostat.

Buying one premium thermostat isn’t a major expense.

Buying 12 of them is.

That’s always been one of our main complaints about the Stelpro Ki.

Multi-zone electric heating may require a thermostat in nearly every room.

So even if the price per thermostat seems reasonable, the total project cost can become substantial very quickly.

Our 12-zone system has justified that expense because the thermostats have been so reliable.

But anyone planning a new multi-zone installation should calculate the complete system cost rather than looking only at the price of one thermostat.

SmartThings Has Worked Extremely Well

Our Stelpro installation has been managed through SmartThings, and we’ve been very happy with the combination.

The thermostat reports its temperature and setpoint to SmartThings, and we can remotely adjust the heating from the same system we use for the rest of the property.

SmartThings also continues to maintain support for Stelpro thermostats through its current Edge architecture.

That’s important for existing owners.

The product may be discontinued, but that doesn’t mean an existing thermostat suddenly stops functioning.

As long as the hardware and smart-home platform continue communicating properly, we plan to keep using ours.

Long-Term Reliability Has Been Excellent

Reliability is the strongest part of this review.

We’ve used these thermostats long enough—and in enough quantity—to have meaningful confidence in them.

Across our 12-zone installation, they’ve simply worked.

That’s more valuable to us than almost any feature on a specification sheet.

Smart-home products are often impressive during the first few weeks of ownership.

Rental automation equipment needs to remain impressive when nobody has thought about it for several years.

The Stelpro Ki has done that.

Should You Buy a Used Stelpro Ki?

We wouldn’t build a new property around used or remaining-stock STZW402 thermostats.

That’s not because we’re worried about the product itself.

We’re worried about what happens later.

If you purchase several discontinued thermostats today and one fails two years from now, finding an identical replacement may become increasingly difficult.

That can leave you with a mixed thermostat system or force you to replace more equipment than expected.

For someone who already owns Stelpro Ki thermostats and needs one replacement, buying another compatible unit may still make sense.

For a completely new installation, we’d choose currently supported hardware.

What Replaces the Stelpro Ki?

This is where things become frustrating.

We haven’t found a current product that is a perfect one-for-one replacement for everything we liked about the Stelpro Ki:

line-voltage electric heat + hub-based control + excellent local usability + Z-Wave.

There are good alternatives.

They’re just different.

Sinopé Zigbee Thermostats Are the Closest Match

The current alternative we’re most interested in for an RHA-style system is Sinopé’s Zigbee line-voltage thermostat family, particularly the TH1123ZB and TH1124ZB models.

These are designed for electric baseboard heaters and similar line-voltage heating systems and support 120V, 208V, and 240V installations. The TH1124ZB supports loads up to 4,000 watts at 240V.

Most importantly for us, they use Zigbee rather than Wi-Fi.

That preserves much of the architecture we liked about the Stelpro.

The thermostat communicates with a hub rather than creating another direct Wi-Fi connection and proprietary cloud dependency.

SmartThings’ current stock Zigbee thermostat Edge driver explicitly includes fingerprints for the Sinopé TH1123ZB, TH1124ZB, and newer G2 versions.

From a technical standpoint, that makes Sinopé one of the most logical products for us to evaluate as a successor.

However, we haven’t accumulated the same years of firsthand STR experience with the Sinopé thermostats that we have with Stelpro.

So we’re not yet replacing Stelpro’s old recommendation with a blanket Sinopé recommendation.

It’s simply the current option we’d investigate first if we were building another hub-based electric-baseboard property.

Mysa Is the More Consumer-Friendly Alternative

The other major alternative is Mysa for Baseboards.

Mysa makes thermostats specifically for line-voltage electric baseboards, convectors, and other compatible electric heating systems.

The current V2 connects directly to 2.4 GHz Wi-Fi, uses the Mysa app for remote management, and includes energy monitoring.

For a typical homeowner, that’s arguably easier.

You don’t need a SmartThings hub.

You don’t need to understand Zigbee or Z-Wave.

You install the thermostat, connect it to Wi-Fi, and manage it through the manufacturer’s app.

For our rental strategy, that’s also its biggest disadvantage.

We generally prefer hub-connected devices over filling a property with individual Wi-Fi devices.

A house with twelve Mysa thermostats would mean twelve additional Wi-Fi-connected smart devices rather than twelve devices living on a dedicated Zigbee or Z-Wave network.

That doesn’t make Mysa a bad product.

It simply makes it a different architecture than the Stelpro Ki system we’ve liked so much.

Mysa also provides useful rental-oriented controls such as minimum and maximum temperature limits and hardware button lockout.

So it absolutely deserves consideration, particularly for owners who prefer a stand-alone thermostat system rather than a broader smart-home hub.

Which Alternative Would We Choose Today?

If we had to replace an entire 12-zone Stelpro system today, we wouldn’t blindly order twelve thermostats without testing them first.

Our first priority would be finding a currently supported hub-connected line-voltage thermostat.

That’s why the Sinopé Zigbee models are particularly interesting to us.

They fit much more closely with the architecture we’ve already proven works well for rental properties.

We would test one or two first, validate SmartThings behavior, remote setpoints, reconnection, guest usability, and long-term stability, and only then consider deploying them throughout an entire property.

If we wanted the simplest consumer-oriented solution and didn’t mind using Wi-Fi and another manufacturer’s app, Mysa would be the other obvious product to evaluate.

What we would not do is buy twelve discontinued Stelpro thermostats simply because we know we like them.

Who Should Still Consider the Stelpro Ki?

A Stelpro Ki may still make sense if:

• You already have an existing Stelpro installation
• You need a compatible replacement for a failed thermostat
• You find legitimate remaining stock
• You understand that future replacement availability is uncertain
• You already use a compatible Z-Wave hub
• You’re comfortable maintaining a legacy device

We would not choose it for a completely new multi-zone installation.