What is the cheapest way to automate my water heater with spot prices?

Open-source Shelly scripts (shelly-porssisahko, Spot-hinta.fi) are free and work well if you are technically comfortable. For most households, a dedicated app like Elewatt is faster to set up and adds savings tracking and filter rules without any coding.

Do I need to switch my electricity supplier to use spot prices?

No — not in Estonia, Latvia, Lithuania, or Finland. All four countries already operate on NordPool day-ahead spot pricing, which your current supplier passes through to your bill. You do not need to sign up for a new supplier or a special tariff. Just connect your device and start scheduling.

What is the difference between Tibber and Elewatt?

Tibber is a full electricity supplier — you must switch your electricity contract to them to use their smart scheduling features. They operate mainly in Sweden, Norway, Germany, and the Netherlands and do not cover Estonia, Latvia, Lithuania, or Finland. Elewatt works with your existing contract and is built specifically for the Baltic and Nordic NordPool markets.

Does Elewatt support Estonia, Latvia, Lithuania, and Finland?

Yes. Elewatt was built specifically for these markets — EE, LV, LT, and FI price zones are all supported. Day-ahead prices are fetched automatically each day after 14:00, and device schedules are updated for the next 24 hours.

Is Home Assistant worth setting up just for water heater scheduling?

If you already use Home Assistant for other things, the NordPool + Shelly integration is excellent and highly configurable. If you only want to schedule a single water heater, the setup cost — dedicated hardware, time to configure, ongoing maintenance — is significant compared to a no-code app that takes minutes to get running.

How much can I realistically save per year with automated scheduling?

Most households in the Baltics see €150–400 per year from water heater scheduling alone, depending on device size and usage patterns. The savings come from shifting 2–4 hours of runtime per day from expensive peak hours to the cheapest hours — typically late night or midday solar. Elewatt tracks actual savings month by month so you can see the real number.

Education HubSmart Home Spot Price Apps

Ecosystem Guide

Smart Home Spot Price Apps: A Guide to the Ecosystem

A look at the tools helping households shift electricity use to cheaper, greener hours — open-source scripts, platforms, and apps, each built for different needs and regions.

Try Elewatt free Education Hub

The Automation Gap

Dynamic electricity pricing is now reality for millions of households in Estonia, Latvia, Lithuania, and Finland. Hourly spot prices swing by a factor of three or more on a typical day — meaning a water heater that runs at 7 AM instead of 3 AM costs two to three times as much. Most people know this. Most people still don't automate around it.

The tools to solve this exist. A growing ecosystem of apps, scripts, and platforms lets households shift water heater, heat pump, and EV charging loads to the cheapest hours automatically. The options look very different from each other — scripts for developers, platforms for DIY enthusiasts, and apps for households who just want it to work.

Typical daily price spread

2–5×

cheapest vs. most expensive hour in Nordic/Baltic markets

Daily runtime needed

2–4 hrs

minimum for a standard 200 L water heater

Annual savings potential

€150–600

per household with automated scheduling

Elewatt price filter dashboard — scheduling devices to run during cheapest electricity hours

Three Ways to Solve It

The solutions fall into three broad categories, each with a different target user, setup complexity, and feature set.

Open-source scripts

Scripts that run directly on the Shelly device itself, fetching NordPool prices and switching the relay without any external server or account. No subscription, no app, no data leaves your network.

✓ Free, private, works indefinitely

✗ Requires developer knowledge to install and configure

Home automation platforms

Home Assistant with NordPool integration gives advanced users complete control — price-based automations for every device in the house. Very powerful once running, but needs a dedicated Raspberry Pi or server.

✓ Highly flexible, large community

✗ High setup barrier, hardware required

Dedicated apps

Cloud-based apps that handle the scheduling logic, UI, and device communication for you. Create an account, connect a device, set your rules. No scripts, no hardware.

✓ No-code, savings tracking, managed updates

✗ Subscription cost, device ecosystem may be limited

Tools Available in 2026

Here is an overview of the main tools helping households make smarter use of spot price electricity as of 2026. Each takes a different approach — the right fit depends on your region, devices, and technical comfort.

Shelly scripts

shelly-porssisahko / Spot-hinta.fi

Script

Device control✓

Baltic/Nordic✓

Savings tracking—

SupplierAny supplier

DevicesShelly only

Home Assistant

Nord Pool + Shelly integration

Platform

Device control✓

Baltic/Nordic✓

Savings tracking—

SupplierAny supplier

Devices10,000+ devices

clever-PV

Germany

App

Device control✓

Baltic/Nordic—

Savings tracking—

SupplierAny supplier

DevicesOpen (SG-Ready)

Tibber

SE / NO / DE / NL

App

Device control✓

Baltic/Nordic—

Savings tracking✓

SupplierMust switch

Devices~15 brands

Volton

App

Device control✓

Baltic/Nordic—

Savings tracking✓

SupplierAny supplier

DevicesVolton only

Gridio

EV charging · 27 EU countries

App

Device control✓

Baltic/Nordic✓

Savings tracking✓

SupplierAny supplier

DevicesBMW, Tesla, VW…

Elewatt

EE / LV / LT / FI (more coming soon)

App

Device control✓

Baltic/Nordic✓

Savings tracking✓

SupplierAny supplier

DevicesShelly + Daikin (growing)

Solution	Type	Device control	Baltic/Nordic	Savings tracking	Supplier	Devices
Shelly scripts shelly-porssisahko / Spot-hinta.fi	Script	✓	✓	—	Any supplier	Shelly only
Home Assistant Nord Pool + Shelly integration	Platform	✓	✓	—	Any supplier	10,000+ devices
clever-PV Germany	App	✓	—	—	Any supplier	Open (SG-Ready)
Tibber SE / NO / DE / NL	App	✓	—	✓	Must switch	~15 brands
Volton EE	App	✓	—	✓	Any supplier	Volton only
Gridio EV charging · 27 EU countries	App	✓	✓	✓	Any supplier	BMW, Tesla, VW…
Elewatt EE / LV / LT / FI (more coming soon)	App	✓	✓	✓	Any supplier	Shelly + Daikin (growing)

Data as of March 2026. Baltic market = Estonia, Latvia, Lithuania, Finland. Savings tracking = built-in cost/savings reporting.

Why the Baltics and Nordics Are Different

Estonia, Latvia, Lithuania, and Finland all operate on NordPool day-ahead spot pricing — the most transparent electricity market in Europe. Day-ahead prices are published each day at 14:00, giving automation tools a full 10+ hours of predictable data before the cheapest window even starts.

This combination of hourly price transparency, high smart meter penetration, and the specific appliances common in the region — 200 L electric water heaters, heat pumps, EV chargers — makes demand shifting unusually effective here. Savings that are theoretical elsewhere are practical in Tallinn, Riga, or Helsinki.

The key difference

You don't need to switch electricity supplier to benefit from spot prices in Estonia, Latvia, Lithuania, or Finland. Your current supplier already passes NordPool prices through to your bill.

Shelly device schedule controlled by Elewatt spot price automation

Open-Source and Dedicated Apps: Different Tools for Different Users

The open-source Shelly scripts — particularly shelly-porssisahko (Finland) and the Spot-hinta.fi scripts — are genuinely excellent. They support the same Baltic/Nordic markets, update device schedules daily, and cost nothing. For a developer or technically confident user, they are hard to beat.

The difference is everything that surrounds the scheduling: a dashboard for settings, savings history over time, filter rules like 'run at least 3 hours between 6 AM and 10 PM', and alerts when prices spike. Dedicated apps add this experience layer for households who want automation to just work — without reading documentation.

🛠 Open-source scripts are great if you...

• Are comfortable flashing firmware and editing config files
• Don't need a UI or savings history
• Want zero monthly cost and full local control

📱 A dedicated app is better if you...

• Want to set it up in minutes without reading documentation
• Want to see how much you've saved month by month
• Want filter rules, notifications, and multiple devices in one place

What to Look for When Choosing

Whichever solution you consider, ask these five questions before committing:

Does it support your country's NordPool price zone? (EE, LV, LT, FI, SE, NO, DK)

Does it work with your current electricity supplier, or do you need to switch?

Can you set minimum runtime rules — e.g. 'run at least 4 hours per day, but not between 6 and 8 AM'?

Does it track and show how much you've actually saved over time?

What is the real setup time? Hours of configuration or minutes?

Elewatt covers the Baltic and Nordic market

No supplier switch needed. Works with your existing Shelly devices. Set filter rules, track savings, get notifications. Free to start.

Try Elewatt free

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