Sources & method

Where the data comes from, which licences apply and how the map turns it into recommendations – including the limits.

How the map calculates

The world is divided into grid cells of 0.5° (about 50 × 50 km). All values are cell averages – valleys, coasts or cities can differ considerably.
Climate values are the average of the last 15 complete years (2011–2025) and are updated every year.
Trends are linear changes of the annual means 1991–2025, given per decade.

Recommendation rules

Atmospheric water generator: dew point above 15 °C or absolute humidity above 12 g/m³ in at least 9 months (“seasonal” from 4 months), plus enough sun or wind. Otherwise: “not worth it”.
Solar power: mean irradiation of at least 3.5 kWh/m² per day.
Wind power: mean wind of at least 4 m/s at 10 m (“good” from 5 m/s).
MOF sorption: relative humidity below 40 % and irradiation of at least 5 kWh/m² per day.
Rainwater harvesting: from 300 mm of annual rainfall. If at least 6 months reach 50 mm each it counts as recommended — otherwise seasonal, because storage has to bridge the dry season.
Fog net: known fog measuring point within 50 km, otherwise an estimate from low clouds and terrain – “good” from 6 fog months, “seasonal” from 3. *
Drinking water from air, rain or fog: always add UV-C and remineralisation.

Thresholds marked with * are still provisional.

Auto mode: baseline assumptions

When a figure required for a calculation is missing, auto mode uses only values explicitly marked as assumption or estimate in data/reference_values.json. Demand-based sizes (such as catchment area or tank volume) are calculated from the entered demand. These are not manufacturer values, are labelled in the builder, and can be overwritten at any time. Costs and fields that cannot be meaningfully calculated remain unknown.

Review status of provisional thresholds

Rainwater harvesting — provisional – confirmed as a screening rule

300 mm/year remains as a conservative first-pass screen. The sources define no universal minimum; demand, catchment area, seasonality, runoff coefficient and storage must be balanced separately.

Reviewed on 2026-09-17.

https://doi.org/10.1007/978-3-031-05710-6

MOF sorption — provisional – confirmed as a screening rule

40% relative humidity and 5 kWh/m²/day remain as a conservative dryness/solar screen. The material, regeneration temperature and energy balance can shift the limit substantially.

Reviewed on 2026-09-17.

https://doi.org/10.1126/science.aam8743 · https://doi.org/10.1016/j.jwpe.2024.106836

Atmospheric water generator — provisional – confirmed as a screening rule

Nine recommended months and four seasonal months remain as an availability screen. This is not a yield guarantee; the humidity and energy conditions still apply.

Reviewed on 2026-09-17.

https://www.ashrae.org/technical-resources/ashrae-handbook · https://doi.org/10.1016/j.rser.2024.114700

Fog net — provisional – confirmed as a screening rule

Six months as good and three as seasonal remain as an ERA5 frequency proxy. Liquid water content, wind, terrain and local measurements determine actual yield.

Reviewed on 2026-09-17.

https://doi.org/10.1007/s13280-012-0247-8 · https://doi.org/10.1016/0168-1923(94)90022-1

Energy and storage balance

Solar and wind values are daily means. Batteries are reported as usable capacity: nominal capacity, DoD, minimum reserve, round-trip and inverter efficiency limit the result; standby consumption increases daily demand. Water production is limited per source by availability, efficiency and processing capacity before it is allocated to demand in a documented order. A tank is only a buffer: its volume is never daily production. Tap water comes exclusively from the municipal network and does not claim local generation. Charge source, grid/off-grid mode, temperature limits and costs remain optional metadata until a time-resolved load and manufacturer balance are available.

Known limits

The fog index detects 11 of 12 known fog measuring points, but captures small islands and narrow coastal mountains poorly and says nothing about water volume.
ERA5 overestimates precipitation in extremely dry mountain and coastal regions (e.g. Atacama).
Wind refers to 10 m height as a cell average; on ridges and coasts it is often stronger, in cities weaker.
Wells, water treatment, dew condensers and plant walls cannot be assessed yet because suitable data is missing.

Data sources

Copernicus ERA5 – climate data

Monthly means of temperature, dew point, solar irradiation, precipitation, wind, low cloud cover and cloud base height on a 0.5° grid. Basis of all map values, recommendations and trends.

Licence: CC BY 4.0
Citation: Hersbach, H. et al. (2023): ERA5 monthly averaged data on single levels from 1940 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). DOI: 10.24381/cds.f17050d7

Required notice (original wording): Contains modified Copernicus Climate Change Service information 1991–2025. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.

Go to source

Base map – OpenFreeMap, OpenMapTiles, OpenStreetMap

Tiles for the base map. Map data © OpenStreetMap contributors. No cookies and no API key are used.

Licence: ODbL 1.0 (OpenStreetMap) · MIT (OpenFreeMap) · © OpenMapTiles

Go to source · OpenStreetMap · OpenMapTiles

Current weather – MET Norway (Locationforecast 2.0)

Only the “Weather now” panel on the map and the builder: weather-model values for the current hour, fetched through our server and cached. Not used in any recommendation or calculation.

Licence: CC BY 4.0

Go to source

Coasts, borders and cities in the VR room – Natural Earth

Only the VR globe: coastlines, lakes, country borders and cities above one million people from Natural Earth (1:50 million scale), condensed in advance into a small file (about 275 kB) served from our own server. The grid cells are clipped at the coast; land without a cell shows as “no data”. Borders are a map drawing, not a legal statement.

Licence: Public domain, no attribution required – we name the source anyway

Go to source

Terrain in the VR room – Copernicus DEM GLO-30

Only the terrain stand in the VR room: heights around the place of each example system (12 × 12 km), averaged in advance to a grid of about 250 m and served from our own server. Heights are drawn three times exaggerated; it is an illustration, not a plan – it shows no single houses, slopes or trees, and the system does not stand on it to scale. The sun paths are calculated (declination and hour angle, accurate to about half a degree, no clock time).

Licence: Copernicus licence: free of charge, commercial use allowed, attribution required

Required notice (original wording): Contains modified Copernicus DEM GLO-30 data (© DLR e.V. 2010-2014 and © Airbus Defence and Space GmbH 2014-2018, provided under COPERNICUS by the European Union and ESA; all rights reserved).

Go to source

NASA POWER – cross-check

Used only to check plausibility at test locations, not in the map.

Licence: free to use, attribution requested

Required notice (original wording): The data was obtained from National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division.

Go to source

Fog measuring points

Known measuring points and yields from the literature, mainly Klemm et al. (2012): Fog as a Fresh-Water Resource. AMBIO 41, 221–234. Sources per measuring point:

Alto Patache (Atacama) · Falda Verde (Chañaral) · Mount Boutmezguida (Aït Baamrane) · Anaga (Tenerife) · Tojquia (Huehuetenango) · Dhofar (Oman) · Nefasit / Arborobu · Serra Malagueta (Santiago, Cabo Verde) · Gobabeb (Namib) · Lomas de Atiquipa (Arequipa) · Pathivara (Taplejung) · Garajonay (La Gomera)

Generated surroundings at the place in the VR room

Ground, plants and terrain at the place are generated from rules: the terrain from heights (Copernicus DEM where a tile exists, otherwise from statistics), the sea from the Natural Earth coastline (public domain, 1:50m), the climate zone and the plants from the place’s ERA5 values by the simple rule below. The picture is the same on every visit (fixed seed from latitude and longitude). No photo, no AI images, nothing from the network at run time.

Below 100 mm annual rain: desert; below 250 mm: semi-desert; from 2200 m elevation (and enough rain): highland.
Below 450 mm: steppe; cold and humid (dew point below -4 °C): highland (grey, low).
From 1500 mm rain and 17 °C dew point: tropics; savanna: from 12 °C dew point and below 30° latitude; conifer forest: below 3 °C dew point and from 500 mm; otherwise temperate.

This is our own simple rule with estimated thresholds, not a published classification (the Köppen-Geiger map is noted as a candidate; its licence is unchecked). The plants are typical for the climate zone, not the real vegetation; the fine shape of the terrain is generated, not the real place. The sea is a flat surface at the simplified coastline (off by a few hundred metres, no waves, beach or small bays); only a height tile knows the sea level, otherwise it is assumed.

Weather lab in the VR room

The weather lab shows the same system under different weather. It is not a weather report and not a forecast: no probabilities, no “typical drought years” – you set the number yourself, within the same ranges as “What if?”. All numbers come from the builder's own calculation; the lab only changes its inputs. The table says for each control whether it calculates or only changes the picture.

Control	Effect	How
Month	calculates	Chooses the monthly climate (rain, dew point, sun) at the system's location; water is a monthly balance, the tank shows the level at the end of the month.
Sun time	picture only	Only sets the sun in the picture and the marker on the battery. The daily power curve is the page's fixed curve (6–18 h), not the real sun path.
Less rain	calculates	Rain falls by the same share as precipitation; the spread over the months stays.
Less sun	calculates and picture	Solar yield falls by the same share. The clouds in the picture are illustration only (no documented conversion from clouds to yield).
Warmer	calculates	The dew point rises by the same kelvin (same relative humidity). This only acts on the air-water generator's rule; heat losses of the modules and extra evaporation are not included.

On the model (picture only, no quantities): tank window by the level at month end, rain gutter only with rainwater, operating lamp of the air-water generator by the dew-point rule, solar modules glow with the generation of the chosen hour (share of the day's peak, the page's daily curve), the house window glows while power is being used in that hour (warm: own power covers it, cool: grid import in that hour), the battery gauge shows the charge. A change of the weather picture at the place fades over about a second ("reduced motion": instantly). "Play the day" steps hour by hour from 6 to 18.

Comparison: "Keep for comparison" holds the result as it was at that moment (system, month, numbers); then the board shows the saved one on the left and the current one on the right – even across a change of system (e.g. Mannheim in December against Dubai in July). The saved one does not recalculate; it is two results of the same calculation side by side, not a forecast.

Air water: there is no curve per hour or temperature (manufacturer data is missing); the lab only shows whether the rule (dew point ≥ threshold) applies – the amount stays the reference value. The demo system's battery is a base assumption, not a product. The picture at the place shows a typical month, not weather.

Manufacturer data for building blocks

Metrics stated directly on manufacturer pages and datasheets. Values apply only to the named model and test conditions; unsupported fields remain empty.

Atmospheric water generator (condensation)

Watergen – GEN-M1 product specifications
Retrieved: 2026-09-17. Watergen states for the GEN-M1 'up to' 220 L/day, 350 Wh/L and 2.2 kW at 26.7 degrees and 60 % relative humidity. The figures contradict each other; only the energy demand per litre was taken from them. Raised from 0.35 to 0.5 kWh/L on 2026-09-19: 350 Wh/L is the datasheet's best value under ideal conditions. Overviews give 0.35 to 0.8 kWh/L as the usual range and 0.5 to 1.0 for household units; individual measurements were 0.84 and above, and across different locations consumption spans 0.02 to 3.64 kWh/L. 0.5 is the lower end of the real range - anyone calculating with 0.35 makes the generator look better than it is in operation.
Go to source

UV-C / bacteria filter

VIQUA – VH200 UV System For Home Plus
Retrieved: 2026-09-17. 35 W is the manufacturer's power consumption for the VH200 model; operating hours, flow and lifetime are application-dependent and are not inferred here.
Go to source

Plug-in solar (balcony)

Bundesnetzagentur – Balkon-Solaranlagen
Retrieved: 2026-09-24. Plug-in solar devices may have up to 2,000 W of module power and 800 VA inverter power (Solarpaket I, since 16 May 2024).
Go to source

Radiative cooler

Applied Physics Reviews 6, 021306 (2019) – Radiative sky cooling: Fundamental principles, materials, and applications
Retrieved: 2026-09-23. Net cooling of 40–80 W/m² at night under clear skies; humid air narrows the atmospheric window.
Go to source

Phase 2 – more data for places

Data for a place besides the climate: elevation, country and electricity access, water stress. For each dataset the catalogue states source, licence, retrieval date and what the figure does not say. None of them feed into a recommendation.

Elevation model: available · verified · verified · NOAA NCEI · ETOPO 2022 v1, 60 arc-second, surface elevation (NOAA NCEI)
Electricity access: available · verified · verified · Weltbank · EG.ELC.ACCS.ZS – Zugang zu Elektrizität (% der Bevölkerung) (Weltbank)
Water stress: available · verified · verified · World Resources Institute · Aqueduct 4.0 Country Rankings, Blatt country_baseline, Kennzahl bws, Gewichtung Tot (World Resources Institute)
Groundwater: not available · missing · pending · BGR / WHYMAP · WHYMAP / BGR
Infrastructure: deliberately not used · missing · verified · OpenStreetMap contributors · OpenStreetMap via Overpass

Elevation: ETOPO 2022 (NOAA NCEI, public domain), averaged over the land within a 0.5° cell – not a value for a single point. Countries: Natural Earth 1:110m (public domain). Electricity access: World Bank EG.ELC.ACCS.ZS (CC BY 4.0), country level. Water stress: WRI Aqueduct 4.0 country rankings (CC BY 4.0), a 0–5 indicator for 1979–2019 at country level – it says nothing about groundwater quality or well yield. Groundwater stays out without clarified licence terms, and infrastructure deliberately as well: OSM proximity does not prove a connection. The import contract and update path are documented in data/phase2/.

Prices

Typical market prices researched online (as of 2026-09-19). They live in data/prices.json, apply per build quality and size, and can be overwritten in the builder. They are not quotes and not an endorsement of any manufacturer.

basic: the cheapest workable option, often self-built or second-hand
adequate: what most people buy
high: durable, certified or installed by a professional

Atmospheric water generator (condensation)

Preis je Gerät. Mehr Wasser heißt ein größeres Gerät – im Baukasten wird über die Anzahl skaliert.
basic: 1,400 € – Auftischgerät 8–15 L/Tag, no-name
adequate: 3,500 € – Watergen GENNY / Aquaria Hydropixel
high: 8,000 € – Anlage mit 50 L/Tag

Aquaria – Best Atmospheric Water Generators 2026 – brands compared (Retrieved: 2026-09-18)
https://www.aquaria.world/blog-posts/best-atmospheric-water-generators-2026-home-whole-house-brands-compared

Aquasol – Prices of atmospheric water generators (Retrieved: 2026-09-18)
https://aquasol.cat/en/archivos/prices-atmospheric-water-generators

Well with pump

Bohrung und Pumpe, ohne Genehmigung (je nach Kommune 50–300 Euro).
basic: 600 € – Rammbrunnen in Eigenleistung
adequate: 3,000 € – Bohrbrunnen vom Fachbetrieb
high: 7,000 € – Tiefbrunnen ab 10 m mit Tiefbrunnenpumpe

rechner-portal.de – Brunnen bohren Kosten: Gartenbrunnen Preise berechnen (Retrieved: 2026-09-18)
https://rechner-portal.de/garten-natur/bewaesserung-wasserverbrauch/brunnen-bohren-kosten-rechner

Tap water

Der Anschluss ist da; bezahlt wird der Verbrauch. Der Literpreis steht in modules.json unter cost_eur_per_l.
basic: 0 € – vorhandener Hausanschluss
adequate: 0 € – vorhandener Hausanschluss
high: 0 € – vorhandener Hausanschluss

BDEW / wasser-experte.net – Was kostet ein Kubikmeter Wasser? Preise 2026 (Retrieved: 2026-09-18)
https://wasser-experte.net/was-kostet-ein-kubikmeter-wasser/

Rainwater harvesting

Nur das Auffangen: Filter, Zuleitung, Anschluss. Das Dach ist vorhanden, der Speicher wird als eigenes Modul gerechnet.
basic: 60 € – Fallrohrfilter mit Regensammler
adequate: 250 € – Filterkorb, Zuleitung, Überlauf
high: 900 € – Filterschacht mit Erdleitung

regenwasser-haushalt.de – Was kostet eine Zisterne? Preise, Einbau und Förderung 2026 (Retrieved: 2026-09-18)
https://www.regenwasser-haushalt.de/kosten/

Fog net

Preis je Quadratmeter Netzfläche, mit Rahmen und Rinne.
basic: 40 €/Net area (m²) – Raschelnetz auf Selbstbaurahmen
adequate: 120 €/Net area (m²) – Industrienetz auf verzinktem Rahmen
high: 185 €/Net area (m²) – CloudFisher (Aqualonis / WasserStiftung)

wissenschaft.de – Innovativer Nebelkollektor fischt Wassertröpfchen (Retrieved: 2026-09-18)
https://www.wissenschaft.de/allgemein/innovativer-nebelkollektor-fischt-wassertroepfchen/

WasserStiftung – CloudFisher – der Original-Nebelfänger (Retrieved: 2026-09-18)
https://www.wasserstiftung.de/unsere-projekte/cloudfisher/

Activated carbon filter

Preis je Filter, ohne Wechselkartuschen (rund 90 Euro im Jahr).
basic: 60 € – Tischkanne mit Filterkartusche
adequate: 119 € – Aktivkohleblock als Auftischgerät
high: 219 € – Aktivkohleblock unter der Spüle

GrünePerlen – Wasserfilter Test 2026 (Retrieved: 2026-09-18)
https://www.grueneperlen.com/wasserfilter-test-vergleich-2026/

Reverse osmosis

Preis je Anlage, ohne Wechselkartuschen (rund 90 Euro im Jahr).
basic: 249 € – Erweiterungsmodul für vorhandenen Filter
adequate: 399 € – Auftischanlage
high: 599 € – Untertischanlage

GrünePerlen – Wasserfilter Test 2026 (Retrieved: 2026-09-18)
https://www.grueneperlen.com/wasserfilter-test-vergleich-2026/

Water softener (ion exchange)

Enthärtung nach dem Ionenaustauschverfahren, Preis je Anlage ohne Einbau und ohne Regeneriersalz.
basic: 300 € – Kompaktentkalker für eine Zapfstelle
adequate: 729 € – AQMOS Cmx-60 für bis zu 5 Personen
high: 1,500 € – Doppelenthärtung mit Verschneidung

wasserenthaertung.com – Wasserenthärtungsanlagen 2026 – Test und Vergleich (Retrieved: 2026-09-18)
https://wasserenthaertung.com/wasserenthaertungsanlagen/

UV-C / bacteria filter

Preis je Gerät, ohne jährlichen Lampenwechsel.
basic: 55 € – einfacher UV-C-Durchlauf ohne Prüfzeichen
adequate: 95 € – 36-W-Gerät (z. B. Wiltec SunSun CUV-236)
high: 400 € – DVGW-zertifizierte Trinkwasseranlage

Alfiltra – UV-Anlagen zur Wasserdesinfektion (Retrieved: 2026-09-18)
https://www.alfiltra.com/filter-systems/disinfection-systems/uv-systems

Solar, compact/foldable

Steckerfertiges Set je Wattpeak, mit Wechselrichter.
basic: 0.31 €/Peak power (Wp) – Aktionsset 800 W für rund 250 Euro
adequate: 0.5 €/Peak power (Wp) – Balkonkraftwerk 800 W mit zwei Modulen
high: 0.88 €/Peak power (Wp) – Set mit Halterung und Full-Black-Modulen

homeandsmart – Balkonkraftwerk-Kosten 2026 (Retrieved: 2026-09-18)
https://www.homeandsmart.de/mit-welchen-balkonkraftwerk-kosten-muss-ich-rechnen-0008-427885

Solar, scalable

Einzelnes Modul je Wattpeak, ohne Wechselrichter und Montage.
basic: 0.15 €/Peak power (Wp) – Großhandelsmodul 400 W für 60 Euro
adequate: 0.28 €/Peak power (Wp) – 400-W-Modul im Onlinehandel (90–140 Euro)
high: 0.56 €/Peak power (Wp) – Premium-Modul, HJT oder bifazial (150–225 Euro)

42watt – Solarmodul 400 Watt 2026: Hersteller im Vergleich (Retrieved: 2026-09-18)
https://42watt.de/magazin/solarmodul-400-watt

Wind turbine (horizontal axis)

Preis je Watt Nennleistung, schlüsselfertig mit Mast und Anschluss.
basic: 3 €/Rated power (W) – günstigstes Angebot der Klasse (3000 Euro je kW)
adequate: 6 €/Rated power (W) – Marktmittel (6000 Euro je kW)
high: 15 €/Rated power (W) – Markenanlage mit hohem Mast (15000 Euro je kW)

klein-windkraftanlagen.com – Preise für Kleinwindkraftanlagen (Retrieved: 2026-09-18)
https://www.klein-windkraftanlagen.com/allgemein/preise-fuer-kleinwindkraftanlagen-fehlinvestitionen-vermeiden/

windprofit.de – Kleinwindanlage Kosten 2026 (Retrieved: 2026-09-18)
https://windprofit.de/blog/kleinwindanlage-kosten

H-rotor

windprofit.de – Kleinwindanlage Kosten 2026 (Retrieved: 2026-09-18)
https://windprofit.de/blog/kleinwindanlage-kosten

Savonius rotor

windprofit.de – Kleinwindanlage Kosten 2026 (Retrieved: 2026-09-18)
https://windprofit.de/blog/kleinwindanlage-kosten

Darrieus rotor

windprofit.de – Kleinwindanlage Kosten 2026 (Retrieved: 2026-09-18)
https://windprofit.de/blog/kleinwindanlage-kosten

Water tank

Preis je Liter Speichervolumen.
basic: 0.07 €/Volume (L) – gebrauchter IBC-Container, 1000 L ab 70 Euro
adequate: 0.3 €/Volume (L) – neuer Behälter oder Regentonne
high: 0.8 €/Volume (L) – Erdzisterne, eingebaut

faesser.de und regenwasser-haushalt.de – IBC-Wassertank 1000 l; Zisternenpreise (Retrieved: 2026-09-18)
https://www.faesser.de/IBC-Container/IBC-Wassertank/

Cold storage (PCM)

Preis je Kilowattstunde thermischer Speicherkapazität.
basic: 15 €/Capacity (kWh thermal) – Salzhydrat als Schüttgut
adequate: 45 €/Capacity (kWh thermal) – Speichermodul mit organischem PCM
high: 90 €/Capacity (kWh thermal) – fertiger PCM-Pufferspeicher

IREES – Statusbericht Latentwärmespeicher (Retrieved: 2021-02-01)
https://irees.de/wp-content/uploads/2021/02/Status-Bericht-LWS_IREES-Final-002.pdf

Sodium-ion battery

Preis je Kilowattstunde Nennkapazität.
basic: 250 €/Nominal capacity (kWh) – Zellen und Gehäuse in Eigenmontage
adequate: 350 €/Nominal capacity (kWh) – 48-V-Bausatz 10,4 kWh für 3612 Euro netto
high: 450 €/Nominal capacity (kWh) – fertiger Heimspeicher mit Wechselrichter

cleanthinking.de – Natrium-Batterie: Vorteile, Nachteile, Kosten 2026 (Retrieved: 2026-09-18)
https://www.cleanthinking.de/natrium-batterie-vorteile-und-nachteile/

natrium-akkus.eu – 48V 210Ah 10,4 kWh Natrium-Ionen-Akku (Retrieved: 2026-09-18)
https://www.natrium-akkus.eu/produkt/48v-210ah-104-kwh-natrium-ionen-akku-solar-bausatz/

Earth-air heat exchanger

Erdregister zur Vorkühlung der Ansaugluft, Preis je Anlage.
basic: 1,000 € – 40 m Rohr in Eigenleistung
adequate: 1,800 € – 40 m Rohr vom Fachbetrieb
high: 3,500 € – mit Erdarbeiten und Kondensatschacht

Kesselheld – Erdwärmetauscher: Funktion, Arten und Preise (Retrieved: 2026-09-18)
https://www.kesselheld.de/erdwaermetauscher/

Plant wall

Preis je Quadratmeter begrünter Fläche, ohne Pflege (5–70 Euro je laufendem Meter im Jahr).
basic: 35 €/Area (m²) – bodengebunden mit Rankhilfe
adequate: 600 €/Area (m²) – einfaches fassadengebundenes System
high: 1,600 €/Area (m²) – fassadengebunden mit Bewässerung

co2online – Fassadenbegrünung: Kosten, Nachteile, Pflanzen (Retrieved: 2026-09-18)
https://www.co2online.de/modernisieren-und-bauen/anpassung-an-den-klimawandel/fassadenbegruenung-fuers-eigenheim/

Hydroponic tower

Preis je Quadratmeter Anbaufläche, Turm mit Tank und Pumpe.
basic: 100 €/Area (m²) – VertiGrow, 20 Pflanzplätze für 199,99 Euro (rund 2 m²), mit 80-L-Tank und Pumpe
adequate: 230 €/Area (m²) – Tower Garden HOME ohne Beleuchtung, 725 US-Dollar für 32 Plätze (rund 3 m²)
high: 320 €/Area (m²) – Tower Garden HOME mit Beleuchtung, 1.020 US-Dollar

grungarten.de – VertiGrow Hydrokultur Turm – 5 Ebenen für 20 Pflanzen (Retrieved: 2026-09-19)
https://www.grungarten.de/vertigrow-hydrokultur-turm---5-ebenen-fur-20-pflanzen/

Tower Garden (us.towergarden.com) – Tower Garden HOME, ohne Beleuchtung (Retrieved: 2026-09-19)
https://us.towergarden.com/products/tower-garden-home-no-lights

Agrotonomy – How Much Does a Tower Garden Cost? (Retrieved: 2026-09-19)
https://agrotonomy.com/how-much-does-the-tower-garden-cost/

Drip irrigation

Preis je Quadratmeter bewässerter Fläche, Schlauch mit Tropfern und Anschluss.
basic: 0.5 €/Area (m²) – Starterset mit 50 m Tropfschlauch für 39,99 Euro, weit verlegt auf rund 80 m²
adequate: 1 €/Area (m²) – Gardena Micro-Drip Start-Set Pflanzflächen, rund 40 Euro für bis zu 40 m², mit Druckminderer
high: 1.45 €/Area (m²) – Markenset mit Verteilern, 57,10 Euro auf dicht verlegten 40 m²

hausundwerkstatt24.de – Starterset Gartenbeete Tröpfchenbewässerung mit 50 m Schlauch (Retrieved: 2026-09-19)
https://www.hausundwerkstatt24.de/Starterset-Gartenbeete-Troepfchenbewaesserung-mit-50-m-Schlauch

GARDENA – Micro-Drip-System Start Set Pflanzflächen (13015-20) (Retrieved: 2026-09-19)
https://www.gardena.com/de/produkte/bewaesserung/micro-drip-system/micro-drip-system-start-set-pflanzflaechen/967040701.html

Cellfast, Handelspreis – Tropfbewässerungssystem-Set mit 50 m Tropfschlauch (Retrieved: 2026-09-19)
https://www.ebay.de/p/12047990104

Evaporative cooling

Preis je Gerät.
basic: 45 € – NEDIS Mobiler Luftkühler mit Wassertank, 44,95 Euro
adequate: 90 € – Markengerät mit 5- bis 7-L-Tank
high: 119 € – Gerät mit großem Tank und Fernbedienung, rund 119 Euro

homeandsmart.de und ebay.de – Luftkühler-Vergleich 2026; NEDIS COOL113CWT (Retrieved: 2026-09-19)
https://www.homeandsmart.de/luftkuehler-test-vergleich

Handwashing station

Preis je Station mit Becken, Frischwassertank und Abwasserbehälter.
basic: 72 € – COSTWAY Campingwaschbecken, 17-L-Tank, Fußpumpe, 71,91 Euro
adequate: 90 € – Outsunny mit 17-L-Tank, Abwasserbehälter und Seifenspender, 89,90 Euro
high: 500 € – WASHPORT, 60 L Frischwasser und 65 L Abwasser, Fußpumpe, 499,99 Euro

COSTWAY und Outsunny, Handelspreise – Campingwaschbecken mit 17-L-Wassertank und Fußpumpe (Retrieved: 2026-09-19)
https://www.costway.de/campingwaschbecken-mit-17l-wassertank-fusspumpe-handtuchhalter.html

biogreen.world – Mobile Handwaschstation WASHPORT mit Frisch- und Abwassertank (Retrieved: 2026-09-19)
https://biogreen.world/products/mobile-handwaschstation-washport-waschbecken-mit-frisch-abwassertank

Plug-in solar (balcony)

Steckersolar-Set (Balkonkraftwerk) je Wattpeak, mit Wechselrichter. Gleiche Marktspanne wie beim kompakten Set.
basic: 0.31 €/Peak power (Wp) – Aktionsset 800 W für rund 250 Euro
adequate: 0.5 €/Peak power (Wp) – Balkonkraftwerk 800 W mit zwei Modulen
high: 0.88 €/Peak power (Wp) – Set mit Halterung und Full-Black-Modulen

homeandsmart – Balkonkraftwerk-Kosten 2026 (Retrieved: 2026-09-18)
https://www.homeandsmart.de/mit-welchen-balkonkraftwerk-kosten-muss-ich-rechnen-0008-427885

Inverter

Wechselrichter je Watt AC-Leistung, Gerät ohne Installation.
basic: 0.15 €/AC power (W) – sehr günstiges Gerät (unter 180 Euro je kW)
adequate: 0.19 €/AC power (W) – Marktmittel 2026 (rund 190 Euro je kW)
high: 0.3 €/AC power (W) – teures Markengerät (über 300 Euro je kW)

energie-experten.org – Wechselrichter-Kosten 2026: Preise, Hersteller & Wartung (Retrieved: 2026-09-24)
https://www.energie-experten.org/erneuerbare-energien/photovoltaik/wechselrichter/kosten

Prices in euro including VAT, without installation and without running costs unless stated. Named products are examples the price is measured against. Building blocks without price tiers (dew condenser, MOF sorption, solar container, gravity storage) have no comparable market price – there the price stays empty.

Software

MapLibre GL JS (BSD-3-Clause), Astro (MIT), React (MIT).

Lifetime of the building blocks

The builder uses these values to spread the purchase cost over the years ("What 1,000 litres cost", "What a kilowatt-hour costs"). Without interest, maintenance and installation.

Solar, compact/foldable: 25–30 years – Umweltbundesamt, 2026-09-24
Plug-in solar (balcony): 25–30 years – Umweltbundesamt, 2026-09-24
Solar, scalable: 25–30 years – Umweltbundesamt, 2026-09-24
Solar container: 25–30 years – Umweltbundesamt, 2026-09-24
Wind turbine (horizontal axis): 20 years – IEC, 2026-09-24
H-rotor: 20 years – IEC, 2026-09-24
Savonius rotor: 20 years – IEC, 2026-09-24
Darrieus rotor: 20 years – IEC, 2026-09-24
Inverter: 10–15 years – 42watt (Fachmagazin, Zusammenfassung von Herstellerangaben und Fraunhofer), 2026-09-24
Sodium-ion battery: from the cycle count at one cycle a day, at most 20 years
Water tank: 20–30 years – Tankworld Australia; Rapid Plas (Hersteller), 2026-09-24
Fog net: 10–20 years – Wasserstiftung, 2026-09-24
Reverse osmosis: 2–3 years – US Water Systems; Membrane Solutions (Hersteller), 2026-09-24
Activated carbon filter: replaced once the cartridge capacity has flowed through
Chemical filter: replaced once the cartridge capacity has flowed through
Water softener (ion exchange): replaced once the cartridge capacity has flowed through
Remineralisation: replaced once the cartridge capacity has flowed through
Heat pump: 20 years – VDI, 2026-09-24

No documented lifetime, therefore not included: Atmospheric water generator (condensation), Well with pump, Rainwater harvesting, Dew condenser, MOF sorption, UV-C / bacteria filter, Sink adapter, Cold storage (PCM), Gravity storage: pumped water, Gravity storage: weight, Earth-air heat exchanger, Charge controller, Radiative cooler, Wallbox (EV).

Load profile for household electricity

The builder spreads a household's annual consumption over hours and months using the BDEW standard load profile H25. Self-consumption and self-sufficiency follow from it.

BDEW Bundesverband der Energie- und Wasserwirtschaft, 2026-09-24. Average over many households, weekdays and weekends combined; a single household has higher peaks.

Reference figures

Droply uses these figures for context. They are averages for Germany; yours may differ considerably.

Water per person per day (households and small businesses): 122 L · BDEW, Wasserfakten im Überblick, As of 2024
Drinking water, volume-based charge (most common tariff type: volume and base charge): €2.06/m³ · Destatis, As of 2025
Drinking water, base charge per household: €107.43/year · Destatis, As of 2025
Wastewater, volume-based charge (most common tariff type: wastewater and rainwater charge): €2.71/m³ · Destatis, As of 2025
Household electricity, average price: 37.0 ct/kWh · BDEW-Strompreisanalyse, As of 2026

Calculated from this: 1,000 litres cost €2.06 for drinking water, €4.77 including wastewater (without base charge). So 122 litres a day cost about 25 cents, about 58 cents including wastewater.

Why the site is designed this way

Some decisions are based on studies. We only use mechanisms that help understanding: no time pressure, no artificial scarcity, no rankings.

Making a guess first makes people more curious about the answer – so we ask for your estimate first. – Brod & Breitwieser (2019), npj Science of Learning doi:10.1038/s41539-019-0056-y
Many people underestimate how much water they use – one reason to put figures in context. – Attari (2014), PNAS doi:10.1073/pnas.1316402111
Sobering figures work mainly when a doable action comes with them – so each one is followed by an option. – Tannenbaum et al. (2015), Psychological Bulletin doi:10.1037/a0039729
People value what they finish building themselves – so you can complete and name your system. – Norton, Mochon & Ariely (2012), Journal of Consumer Psychology doi:10.1016/j.jcps.2011.08.002
Comparisons with the average can backfire – so there are no rankings. – Schultz et al. (2007), Psychological Science doi:10.1111/j.1467-9280.2007.01917.x
The first impression of a page forms within a fraction of a second – so the entry is kept calm. – Lindgaard et al. (2006), Behaviour & Information Technology doi:10.1080/01449290500330448
Evidence for the Namib beetle that catches fog on its back (Namib example). – Hamilton & Seely (1976), Nature 262, 284–285 doi:10.1038/262284a0

How the rating works

The builder says whether a system is sustainable and worth it. Every score comes from the calculation, nothing is estimated on top. These are the thresholds: on the left the value scoring 0 points, on the right the value for 100 points, followed by its weight in the overall score.

Demand covered: 0 → 1 · 30 %
Days the tank lasts: 0 → 3 days · 10 %
Purchase per daily litre: 60 → 3 EUR per L/day · 15 %
Electricity per litre: 0.35 → 0.01 kWh/L · 20 %
Own electricity: 0 → 1 · 15 %
Losses: 0.5 → 0.05 · 10 %
Documented figures: 0 → 1

The thresholds are stated assumptions, not standards – readable and changeable in data/assessment.json. The unfavourable end of each range is used. If the data basis is too thin, no score is given.

Photos

The photos on this website come from Pexels. The Pexels licence allows commercial use and does not require attribution – we credit the photographers anyway.

The pictures are symbolic images: they illustrate the topic and do not show the place of the respective example. The caption says what is actually in the picture.

Earth seen from space – Photo: Zelch Csaba · Pexels · Pexels-Lizenz
Solar farm in the desert, aerial view – Photo: Kelly · Pexels · Pexels-Lizenz
Fog bank over the beach of Nazaré, Portugal – Photo: Artūras Kokorevas · Pexels · Pexels-Lizenz
Hands catching water from an outdoor tap – Photo: Gizem Gökce · Pexels · Pexels-Lizenz
Rainwater running off a concrete roof into greenery – Photo: Vũ Bụi · Pexels · Pexels-Lizenz
A rainy day on a street in Singapore – Photo: 小和尚温柔的 · Pexels · Pexels-Lizenz
Rugged coast of Chile, aerial view – Photo: Luis Garces · Pexels · Pexels-Lizenz
Wind ripples on a sand dune – Photo: MART PRODUCTION · Pexels · Pexels-Lizenz
Sand dune in the desert near Dubai – Photo: MART PRODUCTION · Pexels · Pexels-Lizenz
Berber village in the Atlas Mountains, Morocco – Photo: Pierre Matile · Pexels · Pexels-Lizenz
The village of Marango Rangarik in Himachal Pradesh, India – Photo: Harsh Kukadiya · Pexels · Pexels-Lizenz
Fog over Quiché in the Guatemalan highlands – Photo: Diego Girón · Pexels · Pexels-Lizenz
Laurel forest in fog, Madeira – Photo: Daria Agafonova · Pexels · Pexels-Lizenz
Ancient laurel trees in the misty forest of Madeira – Photo: Daria Agafonova · Pexels · Pexels-Lizenz
Terraces in Valle Gran Rey, La Gomera – Photo: Liisbet Luup · Pexels · Pexels-Lizenz
Wind turbines on the coast at Hvide Sande, Denmark – Photo: Wolfgang Weiser · Pexels · Pexels-Lizenz
Goats in a dry, sandy landscape – Photo: Christophe Rascle · Pexels · Pexels-Lizenz
Volcanic landscape on Lanzarote – Photo: Mihai Vlasceanu · Pexels · Pexels-Lizenz
Cliffs near Vallehermoso, La Gomera – Photo: Liisbet Luup · Pexels · Pexels-Lizenz
Arid mountain desert from the air – Photo: Coral Grandbois · Pexels · Pexels-Lizenz
Cracked, dried-out soil – Photo: icon0.com · Pexels · Pexels-Lizenz
Community garden with blue rain barrels – Photo: Eva Bronzini · Pexels · Pexels-Lizenz
Singapore skyline under rain clouds – Photo: Ravish Maqsood · Pexels · Pexels-Lizenz
Fog bank over a rocky coast – Photo: Kindel Media · Pexels · Pexels-Lizenz
Sand dunes in the desert near Dubai in haze – Photo: Kadir Avşar · Pexels · Pexels-Lizenz
Dune in the Namib Desert under clouds – Photo: Francesco Ungaro · Pexels · Pexels-Lizenz
Fog over fields at dawn – Photo: Rickie-Tom Schünemann · Pexels · Pexels-Lizenz
Raindrops falling from a gutter – Photo: Zeynep Sude Emek · Pexels · Pexels-Lizenz
Fog over hills at sunrise in South Africa – Photo: Raihaan Kamdar · Pexels · Pexels-Lizenz
Fogged window with condensation – Photo: Ömer Derinyar · Pexels · Pexels-Lizenz
House with a garden – Photo: Max Vakhtbovych · Pexels · Pexels-Lizenz
Students in a classroom – Photo: Mickael Ange Konan · Pexels · Pexels-Lizenz
Children at a hand pump in a village in India – Photo: Ritesh Arya · Pexels · Pexels-Lizenz
Baumsilhouetten am Uetliberg mit Novembernebel und Sonnenstrahlen – Kuhnmi · CC BY-SA 4.0 · Startseite, Bild neben dem Einstiegstext

Thematic image files

The six uploaded SVG files were found on 17 September 2026, but no verifiable licence or attribution information was available. They are therefore not used as production assets. For photos, locally optimised WebP or AVIF files are preferable to multi-megabyte SVGs.