C4B vs Andrew Marsh's web apps

C4B vs Andrew Marsh's sun path, weather and psychrometric web apps

Andrew Marsh's free web apps visualise a weather file interactively in the browser, as a 3D surface or on a psychrometric chart. C4B takes a different route: one workflow from an address to a full site climate analysis and report.

Last checked13 October 2026

C4B and Andrew Marsh's web apps at a glance

AspectC4BAndrew Marsh's web apps
TypeWeb app, in the browserFree browser apps (described as experimental tools)
PriceFree plan; paid plans from €59/month (cancellation takes effect after 12 billing cycles) or €599/year, with a 7-day free trialFree
Choosing the locationSearch an address or click the map; no weather file neededDrag and drop an EPW file (the Psychrometric Chart app also reads CSV)
Weather dataNearest weather station file (Climate.OneBuilding.Org, usually TMYx) plus, in projects, EPW files built from site-specific reanalysis (ERA5 / ERA5-Land, CERRA, NORA3) at the exact coordinatesThe weather file you load
PrecipitationMonthly totals and rain event intensity from NOAA rain gauges near the site; in projects, site-specific reanalysis at the exact coordinates and a rainfall record from 1941Plots precipitation and snow depth from the loaded EPW file, where it has them
Future climateSSP1-1.9 to SSP5-8.5, any year from 2025 to 2100, in projects on paid plansNot stated on the pages we reviewed
Outdoor comfortUTCI outdoor comfort, including on the Free planNot stated on the pages we reviewed
Passive design strategies (indoor)Passive Design Strategies for Indoor Environments, with seven strategies per bioclimatic method, in projects on paid plans; the chart with the strategy zones drawn on it in the Designer module on Technical and EnterpriseBioclimatic and comfort overlays on the psychrometric chart, with ASHRAE 55 and EN 15251 comfort diagrams
Energy analysisPreliminary hourly energy balance; orientation and aspect-ratio optimization and window shading recommendations (five fixed devices on eight facades) in projects on paid plansNot stated on the pages we reviewed
Design directionIndoor passive design strategies, outdoor comfort strategies, building orientation and aspect ratio, PV panel orientation and window shading recommendations, in projects on paid plansNot provided beyond the bioclimatic overlays on the psychrometric chart
Accessibility of outputGraphics and data interpretation are targeted at laypeople, and can be read by architects and building developers, in addition to more technical personnelInteractive charts you set up yourself, designed partly for teaching; comfort diagrams can go into reports
OutputsInteractive charts; written readings on most charts in projects and a PDF report on paid plans; EPW downloads on Technical and EnterpriseInteractive visualisations; the Psychrometric Chart app also generates ASHRAE 55 and EN 15251 comfort diagrams for reports

Where Andrew Marsh's web apps is strong

  • Free, interactive visualisations, designed partly for teaching and explaining weather data.
  • No installation: drag and drop an EPW file into the browser.
  • The psychrometric chart app includes bioclimatic and comfort overlays.
  • His software page also lists free 2D and 3D sun-path web apps.

Where C4B takes a different approach

  • No weather file needed: start from an address or map point.
  • One integrated workflow covering climate zone, wind, sun, comfort, precipitation, passive strategies and energy.
  • Future climate scenarios and site-specific data in projects, and a PDF report on paid plans.

Andrew Marsh's web apps may suit you better if

  • You want a free, quick visualisation of a weather file you already have.
  • You are teaching psychrometrics or weather data concepts.

C4B may suit you better if

  • You need a complete climate analysis for a real project, starting from its address.
  • You want future climate, comfort and energy results in one place, with a report.

See your site's climate before design begins

Pin any location and get climate, comfort and preliminary energy insight your whole team can read. Start with a 7-day free trial, or book a 30-minute demo.

Free plan; paid plans from €59/month (cancellation takes effect after 12 billing cycles) or €599/year, with a 7-day free trial. No card required. If you add a card during the trial, the plan is charged when the trial ends; otherwise your account moves to the Free plan. See all plans.

Frequently asked questions

Are Andrew Marsh's weather apps still available?

Yes, they are listed on his software page. The change logs on their app pages list Weather Data v0.0.2 (September 2017) and Psychrometric Chart v0.0.3 (August 2019) as the latest versions.

Does C4B have a psychrometric chart?

Yes, including on the Free plan with weather-station data. Paid projects add passive design strategies, with the share of hours each one covers.

Do I need an EPW file for C4B?

No. C4B finds the nearest station's weather file itself and can compile site-specific data for projects.

Sources

Information about Andrew Marsh's web apps comes from its official website and documentation, checked on 13 October 2026. Products change, so check the official site for the latest details. Andrew Marsh's web apps belongs to Dr Andrew Marsh; C4B is not affiliated with or endorsed by them.

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