ampworth

The command line for Ampworth: UK solar PV and heat pump calculators that follow the published MCS standards and show their working, and the guides that explain them. It also runs as a local MCP server, so AI assistants can use the same tools.

$ ampworth run heat-pump-size --location birmingham --annual-fuel-use 12000 --bedrooms 3 --quoted-heat-pump-kw 12
Estimated peak heat loss: 3.5 kW, so the heat pump has to deliver at least that at -3.2 C outside and 45 C flow.
...

It's a thin client for Ampworth's public API. The calculations run on ampworth.com, so the CLI always gives the same answers as the website, and it needs an internet connection.

Install

With Homebrew, on macOS or Linux:

brew install ampworth/tap/ampworth

With Go 1.27 or later:

go install github.com/ampworth/cli/cmd/ampworth@latest

Or download a binary for macOS, Linux or Windows from the releases page.

Related MCP server: unofficial-solaredge-mcp

Use

ampworth list                       # the calculators
ampworth describe solar-pv-output   # the fields a calculator takes
ampworth run solar-pv-output --postcode "BS1 5TR" --capacity-kwp 4.4 --orientation 30 --inclination 35
ampworth search "flow temperature"  # search the guides, articles and questions
ampworth docs --kind guide          # list the documents
ampworth read guides/sizing-a-heat-pump

Fields are flags named after the calculator's fields, in kebab case (--capacity-kwp) or as written in the API (--capacityKwp). A field that takes a list, such as a room's elements, takes its JSON array as the value. A yes-or-no field given on its own, such as --include-battery, means yes.

Add --json to any command for the API's JSON instead of text. Use --api <url>, or set AMPWORTH_API, to point at a different copy of the API.

Calculators

The list comes from the API each time, so a calculator added to Ampworth appears here without a new release.

Use it with an AI assistant

ampworth mcp runs a local MCP server over standard input and output, with every calculator as a tool, plus list_calculators, search_documents, get_document and list_documents. Add it to any client that starts local servers:

{
  "mcpServers": {
    "ampworth": {
      "command": "ampworth",
      "args": ["mcp"]
    }
  }
}

Claude Code:

claude mcp add ampworth -- ampworth mcp

If your client connects to remote servers, you don't need the CLI: use https://ampworth.com/mcp directly. See ampworth/mcp. For guided workflows, such as checking a heat pump quote, see ampworth/skills.

Data

The CLI sends only the inputs each request needs, such as a postcode, a roof direction or a year of energy use, to https://ampworth.com/api/v1. It stores nothing and sends nothing else. The server works the answer out and doesn't store the request. Like any web server, it keeps a request log for 30 days. The privacy policy has the details.

Scope

The methods and data cover the United Kingdom only. The answers are for understanding a system and checking a quotation. An installation still needs a survey and a design from a certified installer. Ampworth isn't affiliated with MCS, sells nothing and recommends no installer.

Releasing

Releases run on a Mac, because the macOS binary is signed with codesign and notarised with notarytool, using credentials in the keychain:

1. Once: make notary-setup stores a notarytool profile with your Apple ID and an app-specific password. The Developer ID Application certificate must be in the keychain too.

2. make tag VERSION=v0.2.0 tags the version and pushes the tag.

3. make release-check checks everything a release needs.

4. make release builds every binary, signs and notarises the macOS one, publishes the GitHub release, and updates the cask in ampworth/homebrew-tap.

It uses your gh login for GitHub. Optional settings are in .env.release.example.

Support

Email support@ampworth.com or open an issue. Terms of use.

Licence

MIT.