How it should work you can see in the attached xlsx file.
The calculation of the major part "Heizkosten" already works great.
Small changes to do:
1. The new fields, in xlsx file it is field I4 and I38, should be applied in the calculation.
2. Make the sliders work in both directions - number input should move the silder to the correct position.
New things to do:
3. Make chart like in xlsx file using flotchart (www.flotcharts.org) for "Heizkostenvergleich: Gesamtkosten / Jahr" and make Checkboxes like http://www.flotcharts.org/flot/examples/series-toggle/index.html
4. Make chart like in xlsx file using flotchart for "Amortisationsrechnung" with 10 and 20 (years) and make Checkboxes like http://www.flotcharts.org/flot/examples/series-toggle/index.html and Cursor like http://www.flotcharts.org/flot/examples/tracking/index.html
all charts must update as you type
Everywhere German number format