More and more households are switching to dynamic electricity pricing. But does simply having a "spot" tariff mean savings? Short answer — no. Savings come not from the tariff itself, but from how your heat pump reacts to price changes.
What Is Nord Pool and Why Does It Matter?
Nord Pool is the Nordic European electricity exchange where prices are set hourly. In the Lithuanian zone (LT), the price depends on demand, production, wind farm output, and cross-border interconnector load.
In practice, this means:
€0.02
Cheapest hour
(windy night)
€0.12
Average price
(2025 average)
€0.40
Most expensive hour
(cold morning)
The difference between the cheapest and most expensive hour — up to 20 times. This means the same kWh of heating energy can cost €0.02 or €0.40. The question is — does your heat pump know when to work?
3 Ways People Try to Solve This
1. Timers and Rules — "from 11 PM to 6 AM"
The simplest approach — set a timer so the heat pump runs at night. This partly works, but:
- The cheapest hour isn't always at night — sometimes wind makes daytime electricity cheaper
- Doesn't account for weather forecast — if tomorrow will be freezing, nighttime heating may not be enough
- Requires manual seasonal adjustments to settings
2. Smart Home Integration — Home Assistant, Shelly
Enthusiasts integrate the Nord Pool API through Home Assistant and control the heat pump via a relay or contactor. This is a better solution, but:
- On/off control — the heat pump either works or doesn't (no nuance)
- Frequent on/off cycling shortens compressor lifespan
- Requires specific knowledge — YAML configuration, API integration, debugging
- Can't see controller internal parameters — doesn't know COP, compressor state
3. Specialized Control System — Direct Controller Integration
The professional approach — an IoT controller that communicates directly with the heat pump controller and plans work schedules and compressor power, not just on/off:
- Work schedule and power planning — the pump runs continuously but more efficiently
- Sees all controller parameters — COP, compressor frequency, EEV opening
- Combines with weather forecast — not just price, but heat demand too
- Automatic anomaly detection — no need to monitor manually
How Much Can You Actually Save?
Savings depend on two main factors:
Price Volatility
The greater the difference between cheapest and most expensive hours — the more you can save. In Lithuania in 2025, the average daily spread was ~3x.
Building Inertia
A home with underfloor heating and good insulation can "store heat" during cheap hours and release it slowly. Radiator systems provide less flexibility.
Typical results by control method:
Is Price the Only Thing That Matters?
No. Price is just one optimization dimension. Fully effective control considers:
- € Electricity price — Nord Pool spot + supplier margin + transmission fee
- 🌡 Temperature — current + 48-hour forecast
- 💨 Wind and humidity — affect heat losses and heat exchanger frosting
- 🏠 Building inertia — how much heat it can absorb and how long it retains it
- 📊 Real-time COP — the actual current efficiency of the pump
Systems like Termalis Control, which read controller data directly, have this information available in real-time. Timers and relays cannot do this.
The Verdict: Is It Worth It?
Yes, it's worth it — but only if the control meets these conditions:
- Control via work planning, not on/off (protects equipment)
- Considers weather forecast, not just price
- System sees controller data — COP, compressor frequency, temperatures
- Comfort isn't sacrificed — the building doesn't cool down, hot water is always available
Summary
- Dynamic pricing is only worth it with smart control — a spot tariff alone doesn't save
- Timers — 5–10%, Home Assistant — 10–15%, Integrated system — 20–30%
- Key data: electricity price + weather forecast + real-time COP
- On/off control damages the compressor — work schedule planning is safe