The first school day after summer doesn’t just mean lunchboxes, gym bags and new routines.
It also means your energy use gets a different flow. Mornings get busier, evenings get cozier, days get shorter and… your peak power can go up. In this blog, we’ll explain what changes, why it matters on your bill, and how a few smart habits can help you save straight away.

What changes in September?

Busier evenings = higher chance of a higher peak.
In many Flemish households, the highest 15-minute peak happens in the evening while cooking and doing laundry. The VREG (Flemish energy regulator) literally mentions this in their tips.

More lighting and hot water.
Shorter days mean more lights during homework time and dinner. Showers after sports or PE also push hot-water use up.

Standby stacks up.
In many homes, 15–50 devices are on standby. That “phantom load” can account for 7–18% of your yearly usage.

Why does this matter on your bill?

1) The capacity tariff looks at your peak power

Since 2023, part of your grid costs is based on the highest 15-minute average (kW) of the month — your peak.
In 2025, 1 kW costs on average €4.41/month (excl. VAT), with a minimum contribution of 2.5 kW. So yes: an extra peak can cost you real money.

Mini example: did your monthly peak rise from 3.8 kW in August to 5.8 kW in September because your oven, hob and dryer ran together? Then you pay roughly:
2.0 kW × €4.41 = €8.82/month (excl. VAT) extra grid costs. (Rule of thumb; exact amounts vary per grid area.)

Fluvius (the grid operator in Flanders) shows that the average household peak often sits around 3.5–4 kW. If you start everything at once, you’ll jump above that fast.

2) Day/night tariff: when is “starting later” still worth it?

If you still have a day/night contract, this generally applies:

• Day: 07:00–22:00

• Night: 22:00–07:00 (and weekends are usually night tariff too)

That can help for your energy price (the supply component), but not for distribution grid tariffs, because those follow the capacity tariff (time-independent).

Heads-up: some municipalities use 21:00–06:00 as the night window — check your own situation.

Smart planning = instant savings (without losing comfort)

1) Spread heavy appliances in the evening

Not everything at once: cook first, then start the dishwasher. Start your washer/dryer later (timer) or after 22:00 if you’re on day/night — and in any case: to keep your peak lower.
This is exactly what the VREG recommends: check your 15-minute usage in Mijn Fluvius and spot your peak moments.

2) Actually switch off standby

TV decoder, game console, chargers, mesh Wi-Fi… Turn them off at night with a (smart) power strip. That can mean 7–18% less yearly usage.

3) Thermostat: 1°C lower = ±7% less heating cost

September/October is the shoulder season. Lower it during the day when nobody’s home, and try 1°C lower in the evening (bonus: blankets are peak cozy).
Underfloor heating tip: don’t set it too low.

4) Smart charging & hot water

Charge your EV outside the cooking/laundry block; set an end time instead of everyone starting at 22:00.
Got an electric boiler or heat-pump boiler? Plan it after the busy evening peak. (Goal: keep your monthly peak low.)

5) Homework = lights on: make it efficient

LED everywhere and “out of the room = lights off”. Place the desk near a window and use daylight when you can.

6) Use your tariff smartly

• Day/night: shift dishwasher & laundry to night/weekend (energy price)

• Dynamic (hourly prices): plan for the cheapest hours. Daytime can be cheap with lots of (solar) production; night can be good too. Check your hourly prices in the Ecofix App!

Back-to-school checklist

• Use a timer for dishwasher/washer/dryer — and don’t run them together with cooking

• Add (smart) power strips with a switch: TV corner, gaming corner, desk

• Thermostat: lower during the day; try 1°C lower in the evening; night to 15–17°C

• EV charging outside the evening rush; set an end time

• LED lighting + the “lights out” habit

• Check Mijn Fluvius: enable 15-minute data and identify your peak

Two common questions

Does day/night still make sense with the capacity tariff?
Yes. Night can still be cheaper for the supply (energy) part, but your distribution grid costs no longer depend on the hour — they follow your peak power.

When does night tariff start?
Typically 22:00–07:00 (and weekends), but some areas use 21:00–06:00. Check your own situation or ask us.

How Ecofix helps

• Motion (dynamic hourly pricing): run devices when prices are lowest and avoid a high evening peak

• Flexy (variable): even without hourly prices, avoiding peaks still pays off because of the capacity tariff

• Insights in our app: spot your busiest moments and build “school-proof” routines