Any help would be appreciated as this is making my shit itch tonight.
I have made a script that tells me the cheap window each day for my immersion heater.
It outputs in UK 24hr but when I use a notification homey sends it in UTC 12hr.
I have re made the variable multiple times, moved my location around and rebooted homey. But it always outputs the notification in UTC and I can not seem to solve it. Anyone any idea how to change it.
Screenshot of the script output and homey notification attached
The variable is a text variable and this is the script I’m using
// ================== CONFIG ==================
const productCode = ‘AGILE-24-10-01’;
const tariffCode = ‘E-1R-AGILE-24-10-01-A’;
const lookAheadHours = 24;
const immersionPowerKW = 3.0;
let windowHours = 2;
const DEVICE_NAME = ‘Immersion Heater’;
// ================== UK TIME FORMAT ==================
function formatUK24(date) {
return new Intl.DateTimeFormat(‘en-GB’, {
timeZone: 'Europe/London',
hour: '2-digit',
minute: '2-digit',
hour12: false
}).format(new Date(date));
}
async function run() {
try {
// ================= LOAD SETTINGS =================
try {
const v = await Homey.variables.get(‘Immersion_Window_Hours’);
windowHours = parseFloat(v) || windowHours;
} catch (e) {}
const now = new Date();
const nowTime = now.getTime();
const url =
`https://api.octopus.energy/v1/products/${productCode}/electricity-tariffs/${tariffCode}/standard-unit-rates/\` +
`?period_from=${now.toISOString()}&period_to=${new Date(now.getTime() + lookAheadHours * 3600 * 1000).toISOString()}`;
// ================= FETCH DATA =================
const response = await fetch(url);
if (!response.ok) throw new Error(`API Error: ${response.status}`);
const data = await response.json();
if (!data.results?.length) {
log('⚠️ No tariff data returned');
return;
}
let rates = data.results
.map(r => ({
from: new Date(r.valid_from),
to: new Date(r.valid_to),
price: Number(r.value_inc_vat)
}))
.sort((a, b) => a.from - b.from);
const slotsNeeded = Math.round(windowHours / 0.5);
let cheapestTotal = Infinity;
let bestIndex = 0;
for (let i = 0; i <= rates.length - slotsNeeded; i++) {
let sum = 0;
for (let j = 0; j < slotsNeeded; j++) {
sum += rates\[i + j\].price;
}
if (sum < cheapestTotal) {
cheapestTotal = sum;
bestIndex = i;
}
}
const start = rates[bestIndex].from;
const end = rates[bestIndex + slotsNeeded - 1].to;
const startTime = start.getTime();
const endTime = end.getTime();
// ================= CALCULATIONS =================
const avgRate = cheapestTotal / slotsNeeded; // p/kWh
const energyKWh = immersionPowerKW * windowHours;
const costGBP = (energyKWh * avgRate) / 100;
const shouldBeOn = nowTime >= startTime && nowTime < endTime;
// ================= LOG OUTPUT =================
log(\`🔥 CHEAP WINDOW FOUND\`);
log(\`Start: ${formatUK24(start)}\`);
log(\`End: ${formatUK24(end)}\`);
log(\`Avg price: ${avgRate.toFixed(2)} p/kWh\`);
log(\`Energy: ${energyKWh.toFixed(2)} kWh\`);
log(\`Cost: £${costGBP.toFixed(2)}\`);
log(\`State: ${shouldBeOn ? 'ON' : 'OFF'}\`);
// ================= SAFE NOTIFICATION (NO TIME PATTERN) =================
const variables = await Homey.logic.getVariables();
const notifyVar = Object.values(variables)
.find(v => v.name === 'Immersion_Notify');
if (notifyVar) {
const message =
`🔥 Immersion Window\n` +
`Start time ${formatUK24(start)}\n` +
`End time ${formatUK24(end)}\n` +
`Avg rate ${avgRate.toFixed(2)} p/kWh\n` +
`Energy ${energyKWh.toFixed(2)} kWh\n` +
`Cost £${costGBP.toFixed(2)}`;
await Homey.logic.updateVariable({
id: notifyVar.id,
variable: {
value: String(message)
}
});
}
// ================= DEVICE CONTROL =================
const devices = await Homey.devices.getDevices();
const heater = Object.values(devices).find(d => d.name === DEVICE_NAME);
if (!heater) {
log('❌ Immersion heater not found');
return;
}
const currentState = heater.capabilitiesObj.onoff.value;
if (shouldBeOn && !currentState) {
await heater.setCapabilityValue(‘onoff’, true);
log('🔥 IMMERSION ON');
}
if (!shouldBeOn && currentState) {
await heater.setCapabilityValue(‘onoff’, false);
log('❄️ IMMERSION OFF');
}
} catch (err) {
log(\`❌ Error: ${err.message}\`);
}
}
await run();
Thanks in advance
