LAMBDA Heating Schedule®

LAMBDA Heat Schedule® “Plug-and-Play Solution”

LAMBDA Heat Schedule® reduces heat pump electricity costs by up to 37 percent.¹ The new “plug-and-play solution” increases efficiency, reduces defrost cycles, and boosts self-consumption of PV power—without requiring additional hardware or integration with other systems.

_{1Simulation scope: Effect of the Heat Schedule® based on a single-family home, for 16 different scenarios, in the year 2025, location: Kirchbichl, Tyrol,}_{LAMBDA Wärmepumpen GmbH, July 2026}

Up to 37% lower heating electricity costs1

Annual savings of up to 400 euros¹

Optimized Operational Planning in 15-Minute Intervals

Greater Efficiency Through the Use of Off-Peak Operating Hours

More PV Self-Consumption: Up to 39% Solar Power Share1

Reduced Grid Power Consumption Through Intelligent Load Shifting

Up to 36% less operation in conditions
prone to ^icing1

"Plug-and-Play Solution": No HEMS, smart meter, or inverter interface required

Heat Efficiently and Reduce Electricity Costs

The LAMBDA Heat Schedule® is an intelligent operational optimization feature that calculates an optimal 24-hour operating strategy based on weather data, dynamic electricity prices, and PV forecasts. The goal is to minimize heating costs while meeting comfort requirements.
The Heating Schedule® processes various data sources and forecasts and uses them to calculate the optimal power distribution for heat pump operation for the coming day, with a 15-minute resolution.

The following factors, among others, are taken into account during optimization:

Outdoor temperature: Higher outdoor temperatures improve efficiency (COP)
Humidity (dew point): High humidity leads to more frequent defrost cycles and can reduce efficiency
Dynamic electricity prices: Off-peak electricity rates are specifically used for heat generation
PV forecast: Self-generated electricity reduces the amount of electricity purchased from the grid at a cost

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Heating Schedule®

Optimization Using Comfort Logic

Throughout the day, as part of the optimization process, rooms may be intentionally overheated or cooled. A power limit can be used to reduce any potential loss of comfort.
The Heat Schedule® is active exclusively for heating and hot water production. This function is deactivated for cooling mode.

Setpoint Configuration Using a Digital Twin

Using a digital twin in the heat pump software, the projected heating costs are calculated for any given time up to 36 hours in advance, based on expected efficiency, electricity costs, and defrost cycles. An algorithm optimizes load distribution throughout the day within comfort limits, with the goal of minimizing heating costs as much as possible over the course of the day. To ensure flexibility in responding to usage patterns and building conditions, the Heat Schedule® adjusts the threshold values for output control and modifies the setpoint temperatures of the individual modules (heating circuits, domestic hot water).

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Heating Schedule Based on Weather Conditions

Heating Schedule Based on Weather Conditions, Dynamic Electricity Rates, and PV Forecast

Flexible user behavior, customized buildings

Each module has its own individual Heat Schedule®.

During off-peak, efficient operating hours, a higher flow setpoint and greater output are enabled.
During peak-rate hours, the flow setpoint and output are reduced, thereby lowering energy consumption.

Hot water production is prioritized during the most cost-effective times of the day.

Simulation Study:
LAMBDA Heat Schedule®

1Simulation Subject: Effect of the Heat Schedule® based on a single-family home, for 16 different scenarios, in the year 2025, location: Kirchbichl, Tyrol, LAMBDA Wärmepumpen GmbH, July 2026

The Heat Schedule® is an operating concept developed by LAMBDA that proactively plans the daily operation of a heat pump: Heating is prioritized when the home’s own PV electricity is available, when electricity is inexpensive, and when the heat pump operates most efficiently—that is, during the mild, dry hours of the day. The building itself serves as a heat storage unit, balancing the amount of heat supplied throughout the day. What makes it unique: The Heat Schedule® requires no interfaces whatsoever—no home energy management system (HEMS), no smart meter connection, and no on-site configuration.

Greater Efficiency & Cost Savings

In the study, the coefficient of performance (COP) of the heat pump rose, for example, from 5.23 to as high as 5.631 for radiant floor heating systems, because heat was generated primarily during the warmer hours of the day.

The LAMBDA Heat Schedule® reduces heat pump electricity costs by up to 37%¹, as demonstrated by the latest simulation study; this translates to savings of up to €400 per year¹—while maintaining the same amount of heat supplied.

Less icing. Less de-icing.

LAMBDA Heating Schedule® - Taking Advantage of the Cheapest and Most Efficient Hours of the Day

The number of full-load hours at risk of icing (heat generation below 3°C with high humidity) decreases by up to 45%¹, because the load shifts from the cold, humid night and morning hours to the drier, warmer midday hours.

Dynamic rate takes effect only with the Heat Schedule®

Without the Heat Schedule®, switching to a dynamic rate plan offers virtually no potential for savings in the simulated year.

However, only with the Heat Schedule® does a significant cost reduction of up to 13%¹ become apparent compared to the standard scenario.

Even without solar power and without a dynamic electricity rate plan, the Heat Schedule® reduces electricity costs.

Simply by operating during more efficient times of the day, savings of approximately €100¹ per year are possible in the cases considered.

“Plug-and-Play Solution” — no interfaces required

The Wärmefahrplan® requires absolutely no interfaces. No home energy management system (HEMS), no connection to smart meters or inverters, no tariff API, and no configuration by an installer, electrician, IT technician, or end customer. This eliminates the typical hurdles associated with such systems: compatibility issues between manufacturers, additional hardware and setup costs, and, last but not least, any additional vulnerabilities that could pose IT security risks in the home network. The Wärmefahrplan® works from day one, in every home, with any electricity rate plan, and with or without a PV system.

Simulation Study: LAMBDA Heat Schedule®

Lower costs.
Lower power consumption.
No additional hardware or interfaces required.

A recent simulation study shows that the LAMBDA Heat Schedule® plans heat pump operation proactively and prioritizes the use of PV electricity, low electricity rates, and efficient operating times. The building serves as a heat storage system—while maintaining a constant amount of heat.

About the Simulation Study

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