Go straight to the right tool
Calculators and tools
What would you like to find out? Compare costs, check your charging window or prepare for your next discussion. See at a glance which information will help you.
No figures of your own yet? Use the explicitly labelled examples in our calculators. An example demonstrates the calculation; it is not a quote for your home.
What would you like to clarify?
Two choices help you find a starting point. All tools remain available below.
01 · Cars & charging
From your charging window to buying a car.
Our calculator
Compare charging electricity costs
How do electricity prices and mileage affect my annual charging electricity costs?
You need: Annual mileage, electricity demand at the charging point and electricity prices for two scenarios.
You get: Annual charging electricity costs and the difference between the scenarios.
What the result tells you
The comparison covers charging electricity. Purchase, insurance and other vehicle costs belong in the total vehicle cost comparison.
Our calculator
Charging demand and time
Is my available time enough to recharge?
You need: Distance driven, electricity demand including charging losses, average charging power and the available time window.
You get: Energy required, calculated charging time and a comparison with your charging window.
What the result tells you
Average power may be lower than the home charger’s rated power. The result is not a charging curve or confirmation of the building’s connection capacity.
Our calculator
Compare public charging tariffs
Which of the two tariffs suits my charging sessions?
You need: Number of sessions and energy per session, energy price, standing charge and possible additional costs.
You get: Monthly costs by category; one-off fees are shown separately.
What the result tells you
You enter the specific tariff conditions yourself. Unknown fees remain unresolved. Check different charging locations or fee rules separately.
Our calculator
Compare total vehicle costs
What does buying another car or keeping my current car cost over the same period?
You need: Purchase quotes, ownership period, mileage, residual values and information on energy, finance and other costs.
You get: Recorded costs for each vehicle, a cost breakdown and a results sheet.
What the result tells you
For two purchases, or keeping your current car versus buying another. Keeping uses depreciation from today. Leasing is not covered. Missing costs prevent a complete ranking.
02 · Solar electricity
Assess your roof. Understand quotes.
Start with an initial roof assessment. Then explore a system option before comparing actual quotes. External tools open on the respective provider’s website.
External map · with guidance
Solar roof map & financial calculator
What potential does my roof offer, and how do consumption, a battery and costs affect the result?
You need: Address, electricity bill, energy unit price and typical consumption times; ideally a PV quote for the cost calculation.
You get: A roof assessment and our step-by-step guide to the integrated financial calculator, including options with and without a battery.
What the result tells you
Map data cannot replace an on-site assessment, structural checks, grid connection checks or a specific yield forecast. The map opens on the LUBW website.
External tool
PhotovoltaikCheck · co2online
Which PV option suits my house?
You need: Postcode, building type, annual electricity consumption and roof information; include any planned heat pump or electric car.
You get: An initial estimate of generation, self-consumption and financial performance for different options.
What the result tells you
A model calculation for guidance, not guaranteed yields or an on-site assessment. For apartment buildings, the check only models exporting all generation, not supplying individual flats.
Next on our website: Compare actual PV purchase quotes →
External tool
Solarisator · HTW Berlin
How do PV, a battery, a heat pump and an electric car work together?
You need: Household electricity consumption and planned system data. To get started, select “Jetzt alle Werte individualisieren” (customise all values now).
You get: A simulation of energy flows and solar self-supply in a single-family house.
What the result tells you
Standardised weather and consumption profiles may differ from your location and daily routine. The model does not replace a specific yield forecast or professional design.
Next on our website: Connect solar PV and your electric car in everyday life →
Our calculator
Compare PV quotes
Do both prices really cover the same services?
You need: Two purchase quotes with PV capacity, package price, components and included or additional work.
You get: Recorded purchase prices, unresolved items and a printable results sheet for discussion with a contractor.
What the result tells you
The comparison covers purchase costs and scope. Missing information or quotes that are not equivalent prevent a price ranking. Yield, return on investment and running costs are not included.
03 · Heating
Consider purchase and operation together.
First assess your current consumption and possible heating options. For the subsequent cost comparison, you need suitable building data and quotes.
External tool
HeizCheck · co2online
Are my heating consumption and costs unusually high?
You need: Building and heating details, plus consumption and costs from at least one billing period.
You get: An assessment, possible savings and guidance on next steps, including for tenants and owners’ associations (WEGs).
What the result tells you
Forecasts depend on the provider’s assumptions. A consumption comparison is neither a heating load calculation nor evidence that a particular heating system suits your building.
Next on our website: Gather documents and questions for heating plans →
External tool
WärmepumpenCheck · co2online
Is my house potentially suitable for a heat pump?
You need: Year of construction, heating system, radiators and renovation status.
You get: An initial assessment of requirements and possible improvements.
What the result tells you
The online assessment does not replace a heating load calculation or the design of heat emitters and flow temperatures. Actual quotes must suit the house.
Next on our website: Compare heating costs using sound quotes →
Our calculator
Compare a heat pump and district heating
What do the two solutions cost over the same period?
You need: Appropriate heat demand, seasonal performance factor (SPF, “JAZ” in German), energy prices, other annual costs, investment and assumed grants for both quotes.
You get: A guided cost comparison including investment and an overview of missing information.
What the result tells you
Prices remain constant in the scenario. Finance, repairs, replacements and residual values can be added. The result confirms neither availability nor technical suitability for your house.
Still missing building data?
Start with the right documents.
Gas or oil consumption is not automatically the useful heat required. An SPF from a brochure also does not necessarily apply to your house.
Start by gathering bills, building data and existing quotes. Our preparation guide helps you record unresolved questions for an energy advice session.
04 · Understand & prepare
Explore how things connect. Record your next steps.
Interactive example
Explore charging times
What changes when four cars charge at different times?
You need: No documents of your own. You can change the charging start and departure time for each car.
You get: A clear illustration of charging demand, time windows and combined power.
What the result tells you
The simplified example explains how the factors interact. It does not control real vehicles or replace grid or charging design.
Our planning tool
My planning sheet
Which question will I clarify next, and with whom?
You need: Your projects, information already known and unresolved questions. Some or all of the six fields may be left open.
You get: A personal basis for discussion that you can copy, download as text, print or save as a PDF.
What the result tells you
Notes and calculator results you choose to add stay in this browser tab. Nothing is sent to the website. Export the plan before ending the session and clear it on shared devices. You can paste external results into your notes.
Continue planning
Coordinate measures and funding.
These links take you to external providers. Their models and privacy notices apply to your entries. You can then check the results against the original conditions and discuss them with a professional.
External tool
ModernisierungsCheck · co2online
Which renovation measures should I consider together?
You need: An energy bill and information about the building’s condition and previous work.
You get: Suggestions for measures, savings, costs and finance.
What the result tells you
The recommendation helps you prepare for energy advice. It does not replace an individual renovation roadmap or a funding approval.
Next on our website: Find suitable energy advice →
External tool
FördermittelCheck · co2online
Which funding programmes might fit my project?
You need: Basic building data and the planned measures.
You get: Information on suitable programmes, contacts and the next steps.
What the result tells you
Results are not funding approvals. Always check conditions, deadlines, available budget and the permitted timing of contracts or work directly with the funding body.
Next on our website: Check funding routes and original sources →
We checked the co2online services and Solarisator linked above against their providers’ information on 28 September 2026.
The linked external tools are in German. Input guidance on this page is in English; provider interfaces and their results may remain in German.
A figure is missing? Turn it into a specific question.
Note which information you need and who can provide it, such as the complete quote price from the contractor or connection options from the grid operator or heat supplier.