Home Energy Calculators
Size a rooftop solar system from annual kWh and peak sun hours: kW, panel count, yearly output, savings and simple payback.
The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Live 402 challenge
Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.
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"description": "Size a rooftop solar system from annual kWh and peak sun hours: kW, panel count, yearly output, savings and simple payback.",
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"peakSunHours": 4.5
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"asOf": "2026-10-11T14:31:36.963Z",
"source": "computed locally",
"reasons": [
"kW = annual kWh / (peak sun hours x 365 x (1 - losses)); output = kW x peak sun hours x 365 x (1 - losses).",
"Savings count only the energy you use: output beyond your use is valued at zero here (export credits vary by utility).",
"…1 more"
],
"summary": "Offsetting 10000 kWh a year at 4.5 peak sun hours and 14% losses needs about 7.08 kW: 18 panels of 400 W (7.2 kW), producing about 10170 kWh a year. Savings about 1600 a year at 0.16 per kWh. Cost 216…",
"verdict": "COMPUTED",
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"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
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"roof shape, tilt, azimuth and shading, which can cut output by 10 to 40% (peak sun hours must already reflect your tilt and location)",
"seasonal and monthly production against your use, battery storage and net-metering rules",
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"systemLossPercent": 14,
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"asOf": "2026-10-11T14:31:36.963Z",
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"kW = annual kWh / (peak sun hours x 365 x (1 - losses)); output = kW x peak sun hours x 365 x (1 - losses).",
"Savings count only the energy you use: output beyond your use is valued at zero here (export credits vary by utility).",
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"annualKwhToOffset": 10000,
"systemLossPercent": 14,
"estimatedYearlyKwh": 10170,
"simplePaybackYears": 13.5,
"roofAreaSquareFeetApprox": 324,
"installedKwDcWithWholePanels": 7.2
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"Savings count only the energy you use: output beyond your use is valued at zero here (export credits vary by utility).",
"…1 more"
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"verdict": "COMPUTED",
"degraded": false,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
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"roof shape, tilt, azimuth and shading, which can cut output by 10 to 40% (peak sun hours must already reflect your tilt and location)",
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"…2 more"
],
"panelCount": 18,
"panelWatts": 400,
"systemKwDc": 7.079,
"peakSunHours": 4.5,
"systemCostNet": 21600,
"yearlySavings": 1600,
"coveragePercent": 101.7,
"systemCostGross": 21600,
"annualKwhToOffset": 10000,
"systemLossPercent": 14,
"estimatedYearlyKwh": 10170,
"simplePaybackYears": 13.5,
"roofAreaSquareFeetApprox": 324,
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"message": "Home Energy Calculators has 9 pay-per-call endpoints (Home energy math for agents: bills, appliance loads, solar sizing, heat loss, HVAC load checks, insulation, water heating, EV charging and fuel cost.), from $0.02 a call. See the full menu and send your agents our way.",
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{
"url": "https://home-energy-calc.x402tookit.com/household-load",
"path": "/household-load",
"what": "Total a list of appliances (watts, hours a day, quantity) into kWh and cost per day, mont…",
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{
"url": "https://home-energy-calc.x402tookit.com/insulation-r-value",
"path": "/insulation-r-value",
"what": "R-value and U-factor of a wall or roof assembly from layers and thickness, with a framing…",
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}Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
Pay 0.02 USDC on Base to 0xb531…2DBDa. The signed payment is good for 5 minutes.
- Paid to
- 0xb531…2DBDa
- USD Coin contract
- 0x8335…02913
- Payment window
- 5 minutes
- As published
- 20000 smallest units
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- DUPiup…eEm8s
- Token contract
- EPjFWd…TDt1v
- Payment window
- 5 minutes
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- 0xb531…2DBDa
- Token contract
- 0x3c49…c3359
- Payment window
- 5 minutes
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- 0xb531…2DBDa
- Token contract
- 0xaf88…e5831
- Payment window
- 5 minutes
The catalog’s raw entry
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"info": {
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"queryParams": {
"annualKwh": 10000,
"panelWatts": 400,
"costPerWatt": 3,
"pricePerKwh": 0.16,
"peakSunHours": 4.5
}
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"output": {
"type": "json",
"example": {
"asOf": "2026-10-11T14:31:36.963Z",
"source": "computed locally",
"reasons": [
"kW = annual kWh / (peak sun hours x 365 x (1 - losses)); output = kW x peak sun hours x 365 x (1 - losses).",
"Savings count only the energy you use: output beyond your use is valued at zero here (export credits vary by utility).",
"…1 more"
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"summary": "Offsetting 10000 kWh a year at 4.5 peak sun hours and 14% losses needs about 7.08 kW: 18 panels of 400 W (7.2 kW), producing about 10170 kWh a year. Savings about 1600 a year at 0.16 per kWh. Cost 216…",
"verdict": "COMPUTED",
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"roof shape, tilt, azimuth and shading, which can cut output by 10 to 40% (peak sun hours must already reflect your tilt and location)",
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"description": "Watts per panel, 100 to 800 (default 400)"
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"description": "Electricity price per kWh, for savings"
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}Provenance
- Seen in the source catalog
- 2026-10-20 20:33Z
- Last indexed by Roundhouse
- 2026-10-22 19:30Z
- Last enriched (probe, favicon, geo)
- 2026-10-21 00:15Z
- x402 version
- 2
- Max timeout
- 300s
- Liveness probe
- HTTP 402
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 4 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service Home Energy Calculators and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=Home%20Energy%20Calculators' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://home-energy-calc.x402tookit.com/solar-sizing, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Either pay over x402 (mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402), or ask me for an organization key, which I create at https://roundhouseai.io/dashboard/connections. If you have neither, ask before going further. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.