Guide to Using the Heat Pump and SPF Calculator

Welcome to our heat pump calculator! With this tool, you can calculate the Seasonal Performance Factor (SPF) of your heat pump according to VDI 4650 and make an informed decision for your heating system. In this guide, I will explain step by step how to use the calculator and interpret the results.

Table of Contents

  1. Introduction
  2. Calculation Principles and Formulas
  3. Step-by-Step Guide
  4. Understanding Results
  5. Hot Water Demand & Heating Strategies 🆕
  6. Heat Pump Catalog vs. Manual Entry
  7. Tips and Best Practices
  8. Frequently Asked Questions (FAQ)
  9. Technical Background Information
  10. Standards and Further Information

Introduction

What is the Seasonal Performance Factor (SPF)?

The Seasonal Performance Factor (SPF), also known as JAZ in German, is the most important efficiency measure for heat pumps. It indicates how much heat a heat pump generates on average per unit of electrical energy over a year.

Simply explained: An SPF of 4.0 means that the heat pump produces 4 kWh of heat from 1 kWh of electricity – 3 kWh come from the environment (air, ground or water), 1 kWh from the electricity.

SPF = Heat produced [kWh/year] / Electricity consumed [kWh/year]

What does this calculator compute?

The heat pump calculator determines based on your inputs:

  • Seasonal Performance Factor (SPF) according to VDI 4650
  • SCOP (Seasonal Coefficient of Performance) – European standard
  • Annual electricity consumption for heating and hot water
  • Operating costs based on your electricity price
  • CO₂ emissions for environmental assessment
  • Monthly breakdown with heat demand and efficiency

Why is the SPF so important?

Criterion Significance
Economics The higher the SPF, the lower the electricity costs
Funding eligibility BAFA funding requires SPF ≥ 3.0 (air-water) or ≥ 3.5 (brine/water)
Environmental impact Higher SPF = lower CO₂ emissions
Sizing Basis for correct system sizing

Good to know: The SPF should not be confused with the COP. The COP is an instantaneous value under laboratory conditions, while the SPF is the average over an entire year under real conditions – and therefore much more meaningful!

Calculation Principles and Formulas

2.1 Basic Principle of SPF Calculation according to VDI 4650

VDI 4650 defines a standardized procedure for calculating the Seasonal Performance Factor. The basic principle is based on the weighted averaging of performance coefficients across different operating states:

SPF = Σ (Qi × COPi) / Σ Qi

Where:

  • Qi = Heat demand at operating point i [kWh]
  • COPi = Coefficient of performance at operating point i [-]

2.2 Coefficient of Performance (COP) at Different Temperatures

The COP of a heat pump strongly depends on temperature conditions. The calculator uses three characteristic operating points:

Operating Point Outside Air Flow Meaning
A-7/W35 -7°C 35°C Cold winter day
A2/W35 +2°C 35°C Typical heating day (standard condition)
A7/W35 +7°C 35°C Mild day, transition period

Notation explained: "A2/W35" means: Air 2°C, Water (flow) 35°C. For brine-water heat pumps, you will find "B0/W35" instead (B = Brine at 0°C).

2.3 Temperature Dependence of COP

The COP decreases with increasing temperature difference between heat source and heating circuit. A rule of thumb:

COP ≈ η × Th / (Th - Tc)

Where:

  • η = Efficiency factor of the heat pump (typically 0.4-0.5)
  • Th = Flow temperature [Kelvin]
  • Tc = Source temperature [Kelvin]

Practical consequence: Reducing the flow temperature by 5 K increases the COP by approximately 10-15%!

2.4 Calculating Annual Heating Demand

The calculator uses the degree-day method to calculate the annual heating demand from the design heat load:

Q_Heat = P_Design × FLH

Where:

  • QHeat = Annual heating demand [kWh/a]
  • PDesign = Design heat load at outdoor design temperature [kW]
  • FLH = Full load hours [h/a]

Full load hours by building standard:

Building Type Full Load Hours [h/a]
Old building (unrenovated) 2,000 - 2,200
Standard (EnEV compliant) 1,800 - 2,000
Low-energy house 1,600 - 1,800
Passive house 1,200 - 1,500

The calculator uses 1,900 full load hours by default, which corresponds to an average building.

2.5 Domestic Hot Water Heat Demand

Hot water demand is calculated according to DIN 4708 or VDI 2067:

Q_DHW = V_Day × ρ × c × ΔT × 365 × f_L

Where:

  • VDay = Daily water consumption [liters]
  • ρ = Water density (1 kg/L)
  • c = Specific heat capacity (1.163 Wh/kg·K)
  • ΔT = Temperature difference (typically 50 K: 10°C → 60°C)
  • fL = Loss factor for storage and distribution (1.15)

Simplified:

Q_DHW [kWh/a] = Liters/Day × 365 × 1.163 × 50 × 1.15 / 1000

2.6 Monthly Calculation

The calculator performs a monthly calculation to reflect seasonal variations:

  1. Outside temperature per month: From climate data (location)
  2. Heating degree days per month: Only days below heating limit temperature (15°C)
  3. Proportional heat demand: Proportional to heating degree days
  4. COP per month: Interpolated from manufacturer data
  5. Electricity consumption per month: Heat demand / COP

2.7 Effect of Legionella Prevention

With activated legionella prevention (weekly heating to 65°C), the electricity consumption for hot water increases:

Q_Legionella = 52 × V_Storage × ρ × c × ΔT_Leg

With:

  • 52 = Weeks per year
  • ΔTLeg = Additional heating (65°C - 55°C = 10 K)

Important: Legionella prevention is mandatory according to DVGW W 551 for large-scale drinking water systems. For single-family homes, it is optional but recommended. The COP drops significantly at high hot water temperatures (from ~3.5 to ~2.0)!

Step-by-Step Guide

3.1 Project Management

Starting a New Project

On the start page, you have two options:

  1. "Start calculation" – Starts the input wizard
  2. Load project – Enter an existing 5-character project key

Project key: After each calculation, you receive a unique 5-character code (e.g., "RZHLL"). With this, you can retrieve your project at any time, edit it and repeat the calculation.

Editing an Existing Project

  1. Load the project using the project key
  2. Click on "Edit" in the results view
  3. The wizard opens with all pre-filled data
  4. Make your changes and recalculate

3.2 Wizard Step 1: Capturing Heat Demand

The first step determines how much heat your heat pump must provide.

Option A: Import from Heat Load Calculation (recommended)

If you have already performed a heat load calculation:

  1. Select "Import from heat load calculation"
  2. Enter the project key of your heat load calculation
  3. The calculator automatically imports:
    • Design heat load [kW]
    • Location data (postal code, city)
    • Outdoor design temperature
    • System temperatures (if defined)

Advantage: The combination of heat load and heat pump calculator provides the most accurate results, as all building parameters are used consistently.

Option B: Manual Entry

If you don't have a heat load calculation:

  1. Select "Manual entry"
  2. Enter the design heat load [kW]
    • If unknown: Approximately 40-60 W/m² for unrenovated old buildings, 20-40 W/m² for renovated buildings
  3. Enter the postal code
    • The calculator automatically determines the location and outdoor design temperature

Specifying Hot Water Demand

Regardless of the data source:

  1. Enter the annual hot water demand [kWh/a]
    • Typical: 1,500 - 3,000 kWh/a for 2-4 people
  2. Or click "Calculate" for the hot water assistant (more details in Chapter 5)

3.3 Wizard Step 2: Selecting a Heat Pump

In this step, you select your heat pump. You have two options:

Option A: Choose from Catalog

  1. First select the heat pump type:

    • Air-water – uses outside air (most common)
    • Brine-water – uses ground heat (probes or collectors)
    • Water-water – uses groundwater

  2. The catalog shows suitable models with:

    • Manufacturer and model designation
    • Nominal output at A2/W35
    • COP at A2/W35
    • SPF (manufacturer specification, if available)

  3. Select a model by clicking on the row

Option B: Manual Entry 🆕

If your heat pump is not in the catalog or you have specific values:

  1. Select "Enter manually"
  2. Enter (optionally) manufacturer and model
  3. Enter the performance data:
    • Nominal output [kW] at A2/W35
  4. Enter the COP values:
    • COP A-7/W35 (at -7°C outside temperature) – for cold days
    • COP A2/W35 (at +2°C) – required field, standard operating point
    • COP A7/W35 (at +7°C) – for mild days

Tip: You can find the COP values in your heat pump's data sheet or on the manufacturer's website. Pay attention to the correct flow temperature (usually W35 = 35°C).

3.4 Wizard Step 3: System Parameters

In the last step, you configure the system temperatures and operating settings.

Heating Circuit Temperatures

Parameter Description Recommendation
Flow temperature Temperature of heating water from heat generator 35°C (UFH) / 55°C (radiators)
Return temperature Temperature of returning heating water Flow minus 5-10 K
Spread Difference flow - return 5-10 K

Golden rule: The lower the flow temperature, the higher the SPF. Each degree less brings approximately 2-3% higher efficiency!

Hot Water Settings

Parameter Description Recommendation
Hot water temperature Storage temperature 55°C (minimum according to DIN)
Legionella prevention Weekly heating to 65°C Optional, but recommended

Electricity Price

Enter your current electricity price (in cents/kWh):

  • Standard household electricity: approx. 28-35 ct/kWh
  • Heat pump tariff: approx. 22-28 ct/kWh (with blocking times)

3.5 Starting the Calculation

After entering all data, click "Calculate SPF". The calculator now performs the following calculations:

  1. Determination of annual heating demand
  2. Monthly distribution by degree days
  3. COP interpolation for each month
  4. Calculation of electricity consumption
  5. Economic analysis

The results are displayed immediately and the project is saved automatically.

Understanding Results

4.1 Main Result Card

The most important key figures at a glance:

Seasonal Performance Factor (SPF)

SPF Value Rating Comment
< 2.5 ⚠️ Critical Not economical, check causes
2.5 - 3.0 🟡 Adequate Acceptable, but room for improvement
3.0 - 3.5 🟢 Good Typical for air-water HP
3.5 - 4.0 🟢 Very good Good brine HP or optimized air HP
> 4.0 ⭐ Excellent Brine/water HP with low system temperatures

SCOP (Seasonal COP)

The SCOP largely corresponds to the SPF, but is calculated according to European standard EN 14825. It is used to compare different heat pumps.

4.2 Energy Key Figures

Key Figure Description
Heating demand Annual heat for space heating [kWh/a]
DHW heat demand Annual heat for hot water [kWh/a]
Total heat demand Sum of heating + hot water [kWh/a]
HP electricity consumption Power consumption of heat pump [kWh/a]
Auxiliary energy Pumps, controls, etc. [kWh/a]
Total electricity consumption Sum of all electrical consumption [kWh/a]

4.3 Economics

Key Figure Description
Electricity costs/year Annual energy costs [€/a]
Electricity price Used electricity price [€/kWh]
Maintenance costs Flat rate for annual maintenance [€/a]
Total costs/year Electricity + maintenance [€/a]

4.4 Monthly Breakdown

The diagram shows for each month:

  • Heat demand [kWh] – bar chart
  • COP [-] – line
  • Electricity consumption [kWh] – derived value

Interesting: In summer, the COP is highest (warm outside air), but the heat demand is minimal (only hot water). In winter, it's the opposite – high demand with lower COP. The SPF is the weighted average across all months.

4.5 Location Information

The result card also shows:

  • Postal code and city of the location
  • Outdoor design temperature [°C] – lowest temperature for design
  • Climate region (if available)

Calculating Hot Water Demand

The hot water assistant helps you realistically determine the domestic hot water demand – because in well-insulated houses, this often accounts for 30-50% of the total heat demand!

5.1 Opening the Assistant

In Wizard Step 1, click on the "Calculate" icon next to the hot water demand. The assistant is divided into two clear tabs:

  • Tab "Consumption" – Determine hot water demand
  • Tab "Heating schedule" – When should the water be heated? 🆕

5.2 Tab "Consumption" – Number of People

The most important input! Select by clicking on the person pictograms:

People Typical Consumption kWh/Year
1 30-40 L/day 800-1,200
2 60-80 L/day 1,400-1,800
3 90-120 L/day 1,800-2,400
4 120-160 L/day 2,200-3,000
5+ 150-200+ L/day 2,800-4,000+

5.3 Shower Behavior

How extensively do the residents shower?

Option Description Factor
Economical 🚿 Short showers 0.7×
Normal 🚿🚿 Average 1.0×
Extensive 🚿🚿🚿 Long showers 1.4×

5.4 Bathtub Use

Option Description Additional
Never 🛁❌ No bathtub 0 L/day
Rarely 🛁 1-2× per week +3 L/day
Regularly 🛁💧 Almost daily +10 L/day

5.5 Dishwasher

Does the household have a dishwasher?

  • Yes: Reduces hot water demand (no hand washing)
  • No: +5 L/person/day for hand washing

5.6 Tab "Heating Schedule" – Preparation Strategies 🆕

In the second tab, you can choose when the hot water should be heated. This has a direct impact on the heat pump's efficiency!

Why is the heating time important? The COP of a heat pump depends on the outdoor temperature. At noon it's warmer than at night – the heat pump works more efficiently. With intelligent choice of heating time, you can save 5-20% electricity!

Available Strategies

Strategy Description Efficiency Advantage
⏰ Keep warm continuously Tank is kept at temperature around the clock Reference
☀️ Heat once daily Heating at a fixed time each day +5-15%
🌅🌆 Heat twice daily Heating in the morning and evening +3-8%
🌞 Solar-optimized (midday) Heating 10am-3pm for maximum PV usage +10-20%
🌙 Night operation Heating at night (10pm-6am) with night tariff −5-15%

Strategies in Detail

☀️ Heat once daily Ideal for most households. Choose 11am-2pm as heating time when the outdoor temperature is highest. The tank keeps the heat until the next day.

🌅🌆 Heat twice daily Good for households with high morning and evening consumption. Example: 6:00 AM (before showering) and 6:00 PM (before dinner).

🌞 Solar-optimized Perfect for households with photovoltaics! Heating automatically occurs between 10am-3pm when:

  • The PV system produces electricity
  • The outdoor temperature is highest

Tip: With a PV system and solar-optimized hot water preparation, you can significantly increase self-consumption and minimize electricity costs!

🌙 Night operation Only useful with a special night electricity tariff (HT/NT). Efficiency is lower (colder outdoor temperature), but can be compensated by cheaper electricity price.

Caution: Night operation reduces efficiency by 5-15% because the outdoor temperature is lower at night. It's only worthwhile if the night electricity price is at least 20% cheaper!

Individual Time Selection

For the strategies "Once daily" and "Twice daily", you can choose the exact time:

  • First heating time: Dropdown selection from 00:00 to 23:00
  • Second heating time: (only for "Twice daily")

Recommended times:

  • 🌡️ Optimal: 11:00 AM - 2:00 PM (warmest time of day)
  • ☀️ With PV: 10:00 AM - 3:00 PM (highest solar irradiation)
  • ❄️ Avoid: 10:00 PM - 6:00 AM (coldest time)

5.7 Result and Adjustment

The assistant always shows at the top:

  • Calculated demand [kWh/a] – based on your inputs
  • Daily consumption [liters] – for plausibility check
  • Per person/day [liters] – should be around 30-50 L

Manual adjustment: If you want to adjust the calculated value (e.g., based on known consumption data), activate the "Manual adjustment" checkbox and enter your value.

5.8 Efficiency Display in Tab

In the "Heating schedule" tab, you'll see an efficiency badge as soon as you choose a strategy other than "Continuously". This shows the expected efficiency improvement (or reduction for night operation).

5.9 DHW Profile is Saved

The complete hot water profile is saved with the project:

  • Number of people and shower behavior
  • Bathtub usage and dishwasher
  • Preparation strategy and heating times 🆕

When reloading, you can adjust all settings directly without having to re-enter everything.

Heat Pump Entry

6.1 Catalog Selection

The heat pump catalog contains current models from renowned manufacturers with verified performance data.

Displayed information:

  • Manufacturer – e.g., Buderus, Viessmann, Stiebel Eltron
  • Model – Complete type designation
  • Output – Nominal heat output at A2/W35 [kW]
  • COP – Coefficient of performance at A2/W35
  • SPF – Manufacturer specification (if available)

Filtering by type:

  • Air-water (AirWater) – Outside air as heat source
  • Brine-water (BrineWater) – Ground via probes/collectors
  • Water-water (WaterWater) – Groundwater

6.2 Manual Entry 🆕

For heat pumps not in the catalog, use manual entry:

Required Fields

Field Description Typical Values
Nominal output A2/W35 Heat output at standard condition 4-20 kW
COP A2/W35 Coefficient of performance at +2°C outside / 35°C flow 3.0-5.0

Optional Fields (recommended)

Field Description Typical Values
Manufacturer Name of manufacturer e.g., "Vaillant"
Model Type designation e.g., "aroTHERM plus 75"
COP A-7/W35 Coefficient of performance at -7°C 2.0-3.5
COP A7/W35 Coefficient of performance at +7°C 4.0-6.0

Where can I find the COP values?

  • Technical data sheet of the heat pump
  • BAFA list of eligible heat pumps
  • Manufacturer configurators online
  • Keymark certificate

6.3 Interpreting COP Values Correctly

The COP values in the data sheet refer to standardized test conditions according to EN 14511:

Notation: A/W or B/W
A = Air, B = Brine, W = Water (flow)
Number = Temperature in °C

Examples:

  • A2/W35 = Outside air 2°C, flow 35°C
  • A-7/W55 = Outside air -7°C, flow 55°C
  • B0/W35 = Brine 0°C, flow 35°C

Attention: COP values at W35 (35°C flow) are significantly higher than at W55 (55°C). Always compare values with the same flow temperature! The calculator internally converts to your actual flow temperature.

Tips and Best Practices

7.1 Choosing Optimal Flow Temperature

The flow temperature is the most important lever for a high SPF:

System Recommended Flow SPF Advantage
Underfloor heating 30-35°C ⭐⭐⭐ Optimal
Wall heating 35-40°C ⭐⭐ Very good
Large-area radiators 40-50°C ⭐ Good
Standard radiators 50-60°C Acceptable
Old radiators >60°C ⚠️ Critical

Optimization tips:

  1. Replace radiators with larger ones → lower flow possible
  2. Perform hydraulic balancing
  3. Optimize individual room control
  4. Adjust heating curve (reduction at mild outside temperatures)

7.2 Optimal Heat Source Selection

Heat Source Advantages Disadvantages Typical SPF
Air Inexpensive, simple Lower efficiency in winter 2.8-3.5
Ground (collector) Stable temperature Large area required 3.5-4.2
Ground (probe) Compact, efficient Expensive, permit required 3.8-4.5
Groundwater Highest efficiency Permit, water quality 4.2-5.0

7.3 Consider Sizing

Common mistake: Oversizing the heat pump! An oversized HP cycles frequently (on/off), which:

  • Reduces efficiency
  • Increases wear
  • Causes noise

Rule of thumb: Choose a heat pump that delivers about 80-100% output at outdoor design temperature. An electric backup heater is sufficient for peak loads.

7.4 Efficient Hot Water Production

Measure Savings Effort
Reduce hot water temperature to 50°C 10-15% Low
Timer-controlled circulation pump 5-10% Low
Instantaneous water heater for peak demand Variable Medium
Combine with solar thermal system 50-70% DHW High

7.5 Plan Monitoring

After installation, you should regularly check:

  • Electricity meter for heat pump (separate meter recommended)
  • Heat meter (often mandatory for subsidies)
  • Operating hours and compressor starts

Check real SPF:

SPF_real = Heat meter [kWh] / Electricity meter [kWh]

Frequently Asked Questions (FAQ)

What is the difference between COP and SPF?

Feature COP SPF
Measurement condition Lab test, defined temperatures Real operation over 1 year
Time period Snapshot Annual average
Significance Comparison under standard conditions Actual efficiency
Typical value 3.5-5.0 (at A2/W35) 2.8-4.5 (full year)

The SPF is always lower than the best COP, as it also considers cold days, hot water preparation and defrost cycles.

Why is my calculated SPF lower than the manufacturer states?

Possible reasons:

  1. Higher flow temperature – The manufacturer often specifies SPF at 35°C
  2. Colder location – Your outdoor design temperature is lower
  3. Hot water share – High DHW demand lowers overall SPF
  4. Legionella prevention – Weekly 65°C heating costs efficiency

What flow temperature do I need for radiators?

This depends on the radiator size:

  • Adequately sized (1:1 replacement): 50-55°C
  • Oversized (e.g., after window replacement): 40-45°C possible
  • Undersized: >60°C required → replacement recommended

Use our heat load calculator to calculate the optimal flow temperature!

Is a heat pump worthwhile with radiators?

Yes, if:

  • Flow temperature ≤55°C achievable
  • SPF ≥ 3.0 realistic
  • Electricity tariff ≤ 30 ct/kWh
  • Alternatively: Gas boiler old and inefficient

No, if:

  • Flow temperature >60°C required
  • Radiators significantly undersized
  • No possibility to increase heating surface area

How accurate is the SPF forecast?

With correct input data (especially COP values and flow temperature), the deviation is typically ±10-15% compared to actual operation.

Factors not considered:

  • User behavior (ventilation, setback periods)
  • Defrost cycles (for air HP in winter)
  • Control losses
  • Buffer storage losses

What SPF do I need for BAFA funding?

As of 2024 (BEG):

  • Air-water HP: SPF ≥ 3.0
  • Brine-water HP: SPF ≥ 3.5
  • Water-water HP: SPF ≥ 3.5
  • Natural refrigerants: Bonus (R290 propane, R744 CO₂)

Tip: The BAFA list of eligible heat pumps can be found at www.bafa.de. The certified SPF values are also stored there.

Technical Background Information

9.1 Heat Pump Principle

A heat pump works like a "reverse refrigerator":

  1. Evaporator: Refrigerant absorbs environmental heat (air/brine/water)
  2. Compressor: Refrigerant is compressed → temperature rises
  3. Condenser: Heat is released to heating water
  4. Expansion valve: Pressure is released → cycle begins again
Environmental heat (3 parts) + Electricity (1 part) = Heating (4 parts)
→ COP = 4

9.2 Typical Values by Heat Source

Air-Water Heat Pump

Parameter Typical Value
Source temperature -15°C to +35°C
Output range 3-20 kW
COP A2/W35 3.2-4.5
SPF 2.8-3.8
Sound power 45-65 dB(A)

Brine-Water Heat Pump

Parameter Typical Value
Source temperature -5°C to +15°C
Ground temperature 8-12°C (year-round)
COP B0/W35 4.0-5.5
SPF 3.5-4.5
Probe length 80-120 m per borehole
Collector area 20-30 m² per kW

Water-Water Heat Pump

Parameter Typical Value
Source temperature 7-12°C
Minimum flow rate 2.5 m³/h per kW
COP W10/W35 5.0-6.5
SPF 4.2-5.2
Well depth 6-15 m

9.3 Effect of Flow Temperature on COP

The following table shows typical COP values for an air-water HP:

Outside Temp. Flow 35°C Flow 45°C Flow 55°C
-7°C 2.8 2.3 1.9
2°C 3.8 3.1 2.5
7°C 4.6 3.8 3.0

Insight: The COP decreases with:

  • Colder outside temperature (→ less environmental heat available)
  • Higher flow temperature (→ greater lift required)

9.4 Monthly Outside Temperatures (Germany)

The calculator uses location-specific climate data. Typical average values for reference:

Month Avg. Temp. Heating Degree Days
January -0.5°C approx. 620
February 0.5°C approx. 550
March 4.0°C approx. 500
April 8.0°C approx. 360
May 13.0°C approx. 220
June 16.0°C approx. 60
July 18.0°C approx. 0
August 17.5°C approx. 0
September 14.0°C approx. 60
October 9.0°C approx. 340
November 4.0°C approx. 480
December 1.0°C approx. 590
Total 8.7°C approx. 3,780 Kd

Standards and Further Information

10.1 Relevant Standards and Guidelines

Standard Content
VDI 4650 Part 1 Calculation of seasonal performance factor (SPF) – short method
VDI 4645 Planning and sizing of heat pump systems
DIN EN 14511 Testing of heat pumps (COP determination)
DIN EN 14825 Testing of heat pumps – SCOP calculation
DIN EN 12831 Heat load calculation
DIN 4708 Hot water demand
DVGW W 551 Drinking water hygiene (legionella)
GEG 2024 Building Energy Act – requirements

10.2 Further Links

10.3 Funding

Currently (as of 2024), heat pumps are funded through the BEG (Federal Funding for Efficient Buildings):

Funding Rate Condition
30% Basic funding for heat pumps
+20% Climate speed bonus (replacement of fossil heating)
+5% Natural refrigerant (R290, R744)
+5% Ground or groundwater HP
Max. 70% When combining all bonuses

Tip: Check the SPF with our calculator before applying! The minimum SPF is a funding requirement. The application must be submitted before commissioning the contractor.

To the Calculator

Ready for your heat pump calculation?

➡️ Start Heat Pump Calculator

If you have questions about the heat load, we recommend first performing our heat load calculation – the results can be imported directly into the heat pump calculator.

Last updated: December 2025