Use the calculator in your assistant
The same math behind the savings calculator is also available as a set of read-only tools an AI assistant can call directly, through the Model Context Protocol (MCP). Ask it a question about rates, an EV, solar or a battery, and it calls one of the eight tools below instead of guessing.
What it answers
Eight tools, each answering one question in plain words:
list_coverage— What can this calculate, and where?get_rate_schedule— When is power cheap or dear on this plan?compare_rate_plans— Which plan costs least for this home?estimate_home_energy— What does this home cost to run, and what would an energy manager save?plan_ev_charging— What does charging cost and when should I charge?size_rooftop_solar— How much does rooftop solar pay here?size_home_battery— Is a battery worth it on this plan?check_balcony_solar— Is plug-in solar legal in my state, and what would it make?
Where it has data
Nine U.S. utility regions — PG&E, SCE, SDG&E, Con Edison, ComEd and Ameren Illinois among them, plus a generic flat-rate option elsewhere — and 17 climate cities for solar and battery estimates. Every answer names the date its data was generated and links back to the same scenario on the calculator.
What it does not cover
- Heating, water heaters, robot vacuums, demand charges, and tiered or baseline-allowance billing.
- Utilities outside the nine listed regions.
- Live prices — every figure traces back to data baked in at build time, dated.
- A hardware price — payback only appears when a cost is given as an input.
- Installer or product recommendations, and no legal advice on state solar law.
What it receives and keeps
It receives only the values an assistant sends to answer the question asked — a utility or state, a home's size, the sizes of its devices. It keeps a count of calls by tool and location to understand use, stores no personal data, and needs no account. See the privacy policy for the full statement.
Add it in ChatGPT
Find "Home Energy Calculator" in ChatGPT's plugin directory by name and turn it on. No setup or account is needed.
Add it in Claude
In Claude's connector settings, add a custom connector pointing at https://calculator-mcp.hungrymachines.io/mcp.