7 ways to control your heating

• Use your solar surplus — use surplus energy for pools, hot tubs, heating systems and other resistive heating elements.
• Share electricity between sites* — control heating at another location remotely.
• Heat using shared electricity only* — follow the available output of your remote solar system.
• Use lower-cost electricity — heat according to your tariff or electricity prices.
• Control from anywhere — with the Shelly app.
• Choose your time and power — match heating to your operating schedule.
• One heater or a heating-element system — three-phase control up to 17 kW for pools, large hot tubs and heating installations.

We will gladly help with setup. Shelly scripts can be prepared or adapted on request.

* Energy-sharing options by country

WodaTherm™ SD-IHC-3P · SKU WTH-SD-IHC-3P

Three-phase multifunction controller 17kW for pools, large hot tubs and heating systems.

Put surplus solar electricity and favourable tariffs to work in larger heating installations. WodaTherm™ SD-IHC-3P controls a compatible resistive heater or a system of heating elements with a combined output of up to 17 kW across three phases. Use it for swimming pools, large hot tubs, thermal stores, building heating and industrial resistive-heating applications. With Shelly automation, you choose when heating runs, how much power it uses and which energy priorities it follows.

With this device, you can:

1. Automate when your heating runs. Set the rules around your installation's needs. Your automation can decide when to start, adjust power as conditions change and stop heating according to your chosen routine.
2. Heat using surplus solar only. With the corresponding metering and energy management in place, make surplus PV electricity your chosen source of heat. The system follows the available power and adjusts the heating load, turning electricity from your roof into hot water or stored warmth.
3. Choose the electricity price you are willing to pay. Heat at cheaper overnight rates or during other low-price periods. When hot water is the priority, you can also allow heating at higher prices. Your automation uses your tariff or an electricity-price data source to make those choices.
4. Take control from your phone. Use Shelly Smart Control on your phone, tablet or computer whenever you want to adjust the heating yourself. Remote access through your Shelly account gives you control while you are away.
5. Set the times that suit your installation. Choose heating windows by hour and day: while your solar panels are generating, during off-peak periods or ahead of your usual hot-water demand. Combine schedules with your other automation rules.
6. Choose heating power and speed. Use a smaller amount of available power for a slower heat-up, or increase power when you want heat sooner. Set power levels, switching thresholds and priorities for your control system to follow.

Choose the combination that suits your installation. Automatic regulation brings together metering, the relevant data and the configured control system.

How much could you save?

Take 6,000 kWh of usable surplus solar electricity a year. With peak electricity at CZK 6/kWh, off-peak electricity at CZK 3/kWh and an export payment of CZK 0.50/kWh, the savings work out as follows.

Where you save	Saving
Without solar: heat at off-peak rates instead of peak rates	CZK 18,000/year
Use surplus solar instead of peak-rate electricity	CZK 33,000/year
Use surplus solar instead of off-peak electricity	CZK 15,000/year

Smart heating should do more than follow a timer. Control it around your solar surplus, electricity prices and preferred heating power. Use the Shelly app for hands-on control, or connect it to a wider energy-management system that uses AI.

Exclusively European high-tech components. Assembled in EU.

Intelligent control for larger heating installations

Control one resistive heater or coordinate a system of compatible heating elements. The three-phase design offers up to 17 kW of combined heating power, with a current limit of 25 A on each phase. Pool heating, large hot tubs and larger heating circuits can follow solar generation, electricity prices and the temperature requirements provided by the configured automation.

The assembled cabinet combines EPCOS interference filtering and Shelly control in one heating-control solution. Exclusively European high-tech components. Assembled in EU.

Your heating system. Our intelligent power control.

Connect compatible three-phase resistive heating equipment or a system of heating elements within the combined 17 kW rating and the 25 A limit on each phase. WodaTherm™ SD-IHC-3P adjusts heating power for pools, large hot tubs, thermal storage and building or industrial heating according to the configured energy priorities.

Keep more of the value of your solar energy

A larger heating installation can use solar energy over longer operating periods. As a transparent example, using 6,000 kWh of surplus electricity instead of purchasing electricity at CZK 6/kWh, while foregoing export income of CZK 0.50/kWh, gives an annual benefit of CZK 33,000. Actual savings follow the energy used, electricity prices and useful heat demand.

The Shelly app, solar automation and AI energy management

Start with manual control in the app, use heating schedules or make your heating part of your home's energy management. A connected supervisory system can also use AI to decide how and when to heat. SD-IHC-3P turns that system's heating request into power for the heating element, using the configured combination of devices, metering and data.

Open Shelly Smart Control

One controller. Your priorities.

Prepare hot water in your chosen morning window. During the day, follow surplus solar generation and adjust heating as other appliances switch on. In the evening, choose your own settings in the app. Your system's configuration determines which rules take priority, giving you heating that fits the way you live.

The assembled control cabinet brings the power electronics, cooling, interference filtering and Shelly automation together for a larger heating installation. Assembled in EU.

Model: SD-IHC-3P. SKU: WTH-SD-IHC-3P.

More ways to put it to work

Pool and hot-tub heating in step with solar generation

Pool heating, hot tubs and larger heating circuits have different operating schedules and heat demands. The supervisory automation combines generation and consumption measurements with the heating request and sends the required power level to SD-IHC-3P. A compatible heater or heating-element system then follows the available energy within its configured limits.

Pool water, a hot tub or a thermal store can retain useful heat for later use. The practical result depends on water volume, temperature, heat losses, available surplus and the operating schedule. Configure these values for the installation and assess energy savings from actual measurements.

Your automation makes the decisions. SD-IHC-3P delivers the power.

The supervisory solar or home-automation system gathers generation and consumption data, sets priorities and sends the power request. SD-IHC-3P controls the heating circuit accordingly. This clear division lets heating become part of a shared energy plan for the home.

Depending on the chosen platform, the energy plan can include other site consumption, battery charging, pool or hot-tub temperature requirements and building heating. Set priorities, time windows and reserves in the supervisory automation.

Three-phase control in an assembled cabinet

The cabinet brings together three-phase 80 A semiconductor power control, an EPCOS interference-suppression filter, a heat sink with fan, Shelly control and the switching components selected for the heating circuit. The assembly current limit is 3 × 25 A. A clearly arranged cabinet keeps the control and power components together for your heating installation.

One heater or a system of heating elements

Use a compatible resistive heater or a system of heating elements for pools, large hot tubs, thermal stores and larger building or industrial heating circuits. The combined controlled output is up to 17 kW, with a current limit of 25 A on each phase. The supervisory automation allocates available energy between heating and other site loads.

How it works through the day

The process starts with measured energy flow. Your automation considers the household's priorities and sets a heating request. When another appliance starts, it can reduce heating power, then increase it again as more electricity becomes available.

Set operating times around pool use, hot-tub use or the heating needs of the building or process. Local control and Shelly remote control let you adapt the schedule to the site.

Technical specifications

Controlled heating output: up to 17 kW total. Supply: three-phase, 400 V AC. Assembly current limit: 3 × 25 A. Load: compatible resistive heater or system of heating elements. Power module: three-phase SSR, 80 A. Filter: EPCOS B84144A0025R000, 25 A. Control: Shelly automation. Construction: assembled cabinet with heat sink and fan. Exclusively European high-tech components. Assembled in EU.

Dimensions: 400 × 300 × 200 mm. Weight: approximately 16 kg.

More platforms and apps

SunnyHome · Cubee · Home Assistant · Shelly Smart Control · Google Home · Amazon Alexa · Apple Home / Siri · Samsung SmartThings · Homey · openHAB · ioBroker · Node-RED · Hubitat · Control4 · Crestron · Symcon and more.

Home AssistantShelly Smart ControlGoogle HomeAmazon AlexaApple HomeCubeeSamsung SmartThingsHomeyopenHABioBrokerNode-REDHubitatControl4CrestronSymcon

Solar surplus diversion for larger heating systems

With energy metering and configured automation, WodaTherm™ SD-IHC-3P directs available solar surplus into pool heating, large hot tubs, thermal storage or another compatible resistive-heating system. A combined controlled output of up to 17 kW provides room for larger heating installations.

The automation monitors generation and consumption and sends a power request to SD-IHC-3P. Heating can increase as more solar power becomes available and decrease when other appliances start or solar output falls.

Shared solar electricity for remotely controlled heating

Use WodaTherm™ SD-IHC-3P to control compatible pool, hot-tub or thermal-storage heating at another site according to shared solar electricity. The supervisory automation combines available generation data and the configured sharing proportion to send a heating-power request over the data connection.

A residential site, pool facility or business premises can take part in a supported local sharing scheme. The configured data connection carries the control request between the sites.

How generation and consumption work together

In Czechia, Elektroenergetické datové centrum (EDC) registers sharing groups and evaluates their shared electricity. Generation and consumption are matched within the same 15-minute interval. Remote heating helps align consumption at the receiving site with available generation. For projects elsewhere, the selected local sharing programme supplies the allocation and time framework.

A simple Shelly script connects solar output and remote heating

The script uses available generation data and the configured sharing proportion to send heating-power requests over the data connection. It can raise power as generation grows, lower it as available energy falls and pause heating when the sharing energy is no longer available. Your hot-water cylinder or suitable resistive storage heater stores the energy for later use.

Example: solar generation at one site, pool heating at another

After local demand is covered, surplus solar output is available for sharing. The script evaluates the share assigned to the pool facility and sends a power request to its SD-IHC-3P. The pool heating-element system follows available generation and the configured temperature priorities.

We will gladly advise on setup and prepare or adapt a Shelly script for your system on request. The official sharing allocation is shown in the relevant scheme’s records.

Energy-sharing options by country

Remote control connects distant sites over a data connection. Shared energy is used within the local sharing scheme and its geographic area.

• Czechia: EDC. Registration and allocation of electricity-sharing groups.
• Germany: Bundesnetzagentur. Official Energy Sharing guidance; sharing providers coordinate implementation with the local grid operator.
• Austria: Österreichische Koordinationsstelle für Energiegemeinschaften. Guidance on energy communities and the right local sharing model.
• Austria: data exchange: EDA. EDA data-exchange infrastructure; current market-participant registration procedures are provided via ebUtilities.
• France: Enedis. Autoconsommation collective: local generation sharing between participating sites.
• Other European countries: Citizen Energy Advisory Hub. The official European map of citizen energy projects helps you find local initiatives.

Optional temperature sensors

Choose 0–4 temperature sensors in the product configuration. The sensors provide temperature readings for monitoring and the configured heating-control system.

Optional DIN-rail relay for remote control of pumps and other equipment

A DIN-rail relay operated by Shelly 1–0 switching lets you remotely switch power loads on and off, typically pumps, for example. The pump can be controlled independently or in coordination with heating (when heating ends or starts). You can also control the connected equipment remotely through Shelly. Select this option independently of the temperature sensors.