API · /degreeday-api

Degree Day API

healthy 3,467 Subscribers

Heating and cooling degree-day maths as an API, computed locally and deterministically. The daily endpoint computes the heating degree days, HDD = max(0, base − mean), and the cooling degree days, CDD = max(0, mean − base), for a single day from a base temperature and the daily mean — or the minimum and maximum, since the mean is taken as their average. The period endpoint sums the degree days over a list of daily temperatures (means or min/max pairs), returning the total HDD and CDD, the count of heating and cooling days and the average temperature — the standard way to characterise a heating or cooling season. The energy endpoint turns degree days into an energy estimate: the heat delivered is UA·DD·24/1000 kWh from the building heat-loss coefficient, the fuel or electricity input is that divided by the boiler efficiency (or a heat-pump COP), and — with an energy price — the cost. Everything is computed locally and deterministically, so it is instant and private. Ideal for building-energy, HVAC and facilities tools, heating-bill and fuel-budget estimation, weather-normalisation and energy-benchmarking apps, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is degree-day demand estimation; for U-value and heat-loss fabric calculations use a U-value API.

api.oanor.com/degreeday-api
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Machine-readable spec so AI agents can integrate this API.

/api/degreeday-api/openapi.json
/api/degreeday-api/llms.txt

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API health

healthy
Uptime
100.00%
Server probes · 24h
Avg latency
88 ms
Server probes · 24h
Subscribers
3,467
active
Total calls
28
last 7 days
status Full status page → · 20 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

Free

  • 2,000 calls / month
  • 2 requests / second
  • Hard cap (429 above quota, no overage)
  • Daily HDD/CDD with a configurable base temperature
  • Celsius and Fahrenheit input
  • 2,000 calls/month for evaluation
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Starter

€9.00 /month

  • 40,000 calls / month
  • 6 requests / second
  • Hard cap (429 above quota, no overage)
  • Heating and cooling degree days per day
  • Custom base temperature per request
  • Batch a month of readings in one call
  • 40,000 calls/month
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Pro

€24.00 /month

  • 250,000 calls / month
  • 18 requests / second
  • Hard cap (429 above quota, no overage)
  • Seasonal and annual degree-day rollups
  • Mean-temperature and integration methods
  • Multi-site building portfolios
  • 250,000 calls/month
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Mega

€74.00 /month

  • 1,500,000 calls / month
  • 50 requests / second
  • Hard cap (429 above quota, no overage)
  • High-volume HVAC and energy-modelling pipelines
  • Bulk historical degree-day backfills
  • Priority deterministic compute
  • 1,500,000 calls/month
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Built by

Related APIs

Other APIs with overlapping tags.

HVAC BTU Calculator API

HVAC sizing maths as an API, computed locally and deterministically from standard rule-of-thumb factors. The cooling endpoint estimates the air-conditioner load for a room — in BTU per hour, tons of cooling and kilowatts — from the floor area (in square feet or metres, or length × width) using a baseline of about 20 BTU/h per square foot, with adjustments for the number of occupants, a kitchen, sun exposure and ceiling height. The heating endpoint estimates the heating load from the area and a climate zone (mild through very cold) or a custom BTU per square foot. The convert endpoint converts between BTU per hour, tons of cooling, kilowatts and watts (one ton = 12,000 BTU/h ≈ 3.517 kW). Everything is computed locally and deterministically, so it is instant and private. These are rule-of-thumb estimates in the EnergyStar style — a proper Manual J load calculation accounting for insulation, windows and local climate is recommended for a real installation. Ideal for HVAC and home-improvement tools, air-conditioner and heater sizing guides, smart-home and energy apps, and contractor quoting. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is HVAC sizing; for appliance running cost use an energy-cost API.

api.oanor.com/hvac-api

Firewood Calculator API

Firewood maths as an API, computed locally and deterministically. The volume endpoint turns a wood-stack's length, height and depth (in feet or metres) into its volume in cubic feet and cubic metres, full cords, face cords and steres — a full cord being 128 cubic feet (a 4×4×8 ft stack) and a face cord being an 8×4 ft stack by the piece (log) length. The convert endpoint converts a quantity between cords, face cords, steres, cubic metres and cubic feet, using the piece length for the face-cord relationship. The heat endpoint estimates the heating value of a number of cords by wood species — returning the millions of BTU and the equivalent gallons of heating oil, therms of natural gas and kilowatt-hours — from a built-in table of typical seasoned-wood values (oak, hickory, maple, ash, birch, pine and more) or a custom figure. Everything is computed locally and deterministically, so it is instant and private. Heat values are typical seasoned figures (around 20% moisture) and vary with species, dryness and stove efficiency. Ideal for firewood sellers and delivery tools, heating and homestead apps, and forestry and woodlot calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is firewood volume and energy; for general volume or unit conversion use a unit-conversion API.

api.oanor.com/firewood-api

Heatsink Thermal API

Heatsink and thermal-resistance maths for electronics as an API, computed locally and deterministically. The junction endpoint computes the junction temperature of a component from its power dissipation, the ambient temperature and the thermal-resistance chain, Tj = Ta + P·(Rθjc + Rθcs + Rθsa) — junction-to-case, case-to-sink (the interface material) and sink-to-ambient — and also reports the case and sink temperatures and, given a maximum junction temperature, the headroom. The required endpoint solves the largest heatsink thermal resistance you may use to stay under a junction limit, Rθsa = (Tj_max − Ta)/P − Rθjc − Rθcs, and flags when no heatsink can do it. The power endpoint gives the maximum power a device can dissipate for a given thermal path, P = (Tj_max − Ta)/Rθtotal. Everything is computed locally and deterministically, so it is instant and private. Ideal for electronics, power-supply and PCB-design app developers, heatsink selection and thermal-budget tools, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is conduction thermal-resistance; for convective Newton cooling use a cooling API.

api.oanor.com/heatsink-api

Propane & LPG Tank API

Propane and LPG tank maths as an API, computed locally and deterministically — the usable-fill, energy and burn-time numbers a homeowner, RV-er, grill-master or HVAC tech works out at the tank. The tank endpoint turns a tank size into real numbers: liquid propane is 4.24 lb per gallon and holds 91,452 BTU per gallon (about 21,569 BTU per pound), so a 20 lb barbecue cylinder carries roughly 4.7 gallons and 431,000 BTU. It knows the two ways tanks are sized — a portable cylinder (20, 30, 40 lb) is rated by the propane weight it holds, while a bulk tank (100, 250, 500, 1000 gal) is filled to only 80 % of its water capacity to leave room for expansion, so a 500-gallon tank actually holds 400 gallons of propane and about 36.6 million BTU. The burntime endpoint divides that energy by an appliance’s BTU-per-hour input rating to give run time: that same 20 lb cylinder runs a 30,000 BTU/hr patio heater about 14 hours, and an optional hours-per-day turns it into days. The refill endpoint costs a fill from a price per gallon, gives the cost per 100,000 BTU so you can compare propane to natural gas or electricity, and — with an appliance rating — the running cost per hour. Everything is computed locally and deterministically, so it is instant and private. Ideal for home-energy, HVAC, RV, off-grid, grilling and outdoor-living app developers, fuel-cost and tank-monitor tools, and propane-delivery calculators. Pure local computation — no key, no third-party service, instant. US units. Live, nothing stored. 3 compute endpoints. For vehicle fuel economy or the ideal gas law use a different API.

api.oanor.com/propane-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Degree Day API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Degree Day API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Degree Day API?
Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.
How much does Degree Day API cost?
Degree Day API has a free tier with 100 calls / month. Paid plans start at €9.00 / month with higher quotas and faster rate limits.
Can I cancel my subscription anytime?
Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.
Is Degree Day API GDPR-compliant?
All requests to Degree Day API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.

Pick an endpoint from the list on the left to see its details and try it.

Code snippets

Sign up to get an API key, then call any path under your slug.

curl https://api.oanor.com/degreeday-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."
const res = await fetch("https://api.oanor.com/degreeday-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();
$ch = curl_init("https://api.oanor.com/degreeday-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);
import requests
r = requests.get(
    "https://api.oanor.com/degreeday-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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