Tempo red day: what to do, hour by hour
A red day is prepared the evening before: here is what costs a lot between 06:00 and 22:00 and what can wait for the night.
On a Tempo red day, each kilowatt-hour used between 06:00 and 22:00 costs €0.7295 on the regulated tariff of 1 August 2026, more than four times the blue-day peak price (€0.1654). After 22:00 and until 06:00 the next morning it drops back to €0.1615. A season holds 22 of them, all placed by RTE between 1 November and 31 March, on weekdays, never on a bank holiday and never more than 5 in a row. The colour is known at 10:30 the day before, which leaves an evening to run appliances, set the water heater and prepare the heating. Useful effort goes into three areas, heating, hot water and appliances that heat up or run for a long time, while lighting, the internet box and the fridge weigh almost nothing. The mini-calculator below puts a figure on the gap for any appliance you choose.
This appliance on a red day, before or after 22:00
Run on a red day between 06:00 and 22:00
€3
| The same evening, after 22:00 | €1 |
| On a blue day, at night | €1 |
| Saving by shifting after 22:00 | €2 |
Tempo kWh prices incl. tax from 1 August 2026.
Checked by Radif Partners · Editorial policy · Method and sources
The day before, from 10:30
RTE publishes the next day’s colour at 10:30 on its Tempo calendar, the only binding source. When tomorrow is red, the evening before becomes valuable: it is billed at the current day’s colour, often blue or white, and every task brought forward escapes red peak prices. Run the dishwasher, start a wash, charge the car to full and let the water heater heat up completely overnight.
If your home is electrically heated, raise the temperature by a degree late in the evening and overnight: the house stores heat in its walls and furniture, which you then use the next day without paying the red price for it. How well this works depends a great deal on insulation, but it costs almost nothing to try.
From 06:00 to 22:00: the expensive hours
For sixteen hours each kilowatt-hour costs €0.7295. The table below prices a few common uses, with power ratings and durations given as examples: swap in those of your own appliances, printed on their rating plate.
| Use (example) | Energy | Red 06:00-22:00 | Red after 22:00 | Blue at night |
|---|---|---|---|---|
| Washing machine, 40 °C cycle | 3.0 kWh | €2 | €0 | €0 |
| Tumble dryer | 5.0 kWh | €4 | €1 | €1 |
| Electric oven | 2.5 kWh | €2 | €0 | €0 |
| 1,500 W radiator | 12.0 kWh | €9 | €2 | €2 |
| Car charging on a reinforced socket | 14.8 kWh | €11 | €2 | €2 |
The lesson fits on one line: something that runs for hours, like a radiator left on for eight, weighs far more than a powerful but brief use. Dinner in the oven costs a few euros; a full day of heating costs tens. That is why most of a red day’s saving comes from heating and hot water, not from lighting.
Heating, without taking risks
Lowering the setting by one or two degrees between 06:00 and 22:00 and raising it again at 22:00 is the most rewarding move. A programmable thermostat does it for you; some receive the Tempo signal straight from the meter and adjust on their own. Do not go too low: a home that gets too cold picks up damp, and warming it back up eats part of the saving. Above all, health comes before the bill: babies, elderly or ill people must stay warm, and a fuel-burning heater in a closed room is dangerous. The guide on electric heating and Tempo shows how much red days weigh in a year of heating.
Hot water, cooking, laundry
A water heater wired to the meter’s off-peak contact heats between 22:00 and 06:00: it uses nothing at red peak time, provided you do not force it on manually. For cooking, favour quick dishes over long oven sessions that day. The washing machine and dryer can easily wait for the night or the next day; a delayed start does the job. An electric car that is plugged in should only charge after 22:00: set the start time in the car or on the wallbox.
After 22:00, and the next day
From 22:00 to 06:00 the price falls to €0.1615. This is when to catch up on whatever was put off. A Tempo day runs from 06:00 to 06:00, so for billing purposes the night still belongs to the red day, at red off-peak rates. Since red days can run up to 5 times in a row on weekdays, check the next day’s colour before restarting everything: the tomorrow’s Tempo colour page shows it as soon as it is out.
How many red days this winter?
The stock is fixed: 22 per season, under the rules of the regulator’s 2014 deliberation. RTE places them when forecast net demand, national consumption minus wind and solar, crosses a threshold that falls as the season goes on, as its method note explains. All 22 days must be placed before 31 March: even a mild winter ends up using them, and the season history shows last red days falling as late as 31 March. The current season’s count is on the Tempo days left page.
Three ways to live the same red day
To measure what the habits are worth, take a house using 40 kWh on a winter day, 30% of it at night, and compare three ways of getting through the day. Costs come from the site’s engine at the red prices of the grid in force.
| How the day is organised | Night share | Energy | Cost of the day |
|---|---|---|---|
| Nothing changes | 30 % | 40 kWh | €22 |
| Appliances, water heater and charging after 22:00 | 45 % | 40 kWh | €19 |
| Same again, heating lowered during the day | 50 % | 34 kWh | €15 |
The first saving comes simply from moving use into the night, with no discomfort at all. The second comes from heating. Together they come close to halving the cost of the day, and that across 22 days each winter.
The mistakes that cost most
The most common is forcing the water heater on manually on a red-day morning because hot water ran out the evening before: a few kilowatt-hours at the top price, when a shorter shower would have lasted until the evening. Next comes the timer set once and for all to a fixed afternoon hour, for a washing machine or a dehumidifier, which nobody thinks to move on red days.
Another trap is the plug-in electric heater switched on in a cold room while the main heating has been turned down. It cancels the effort and often costs more than lowering the whole house by a single degree. Finally, many forget that a red day starts at 06:00: an oven switched on at 06:30 for breakfast, or a charge that runs past 06:00, is already billed at red peak prices.
A household with vulnerable people
Tempo obliges nothing; it encourages. A household with a newborn, an elderly, ill or dependent person must keep a comfortable temperature whatever the colour. Savings then have to be found away from the heating of living rooms: hot water, appliances, cooking, charging. If the heating cannot go down on red days, run the comparison tool again with “Nothing” as the shift: it will tell you whether Tempo still pays for you.
Homes without electric heating
A flat heated by gas or a district network gets through red days far more calmly: its electricity use comes mainly from hot water, cooking, laundry and appliances. For it, the effort often comes down to running nothing large between 06:00 and 22:00 and letting the water heater work at night. Those days then weigh roughly their share of the calendar, and Tempo usually stays the cheapest option, as the home page shows for a typical household without electric heating.
Working from home changes things slightly: a computer, a screen and a hob at lunchtime on a red day add up to only a few kilowatt-hours, but a plug-in heater in the study soon adds up to far more. Better to work in the best-heated room than to warm a cold one with electricity.
The same logic applies to second homes and holiday lets: a property left empty on a red day only needs frost protection, not comfort heating, and a frost setting on each radiator costs a fraction of a normal day.