Usage effect

SpotVahti · updated 12 Nov 2026 · calculated from actual hourly prices for 1 Nov 2025–31 Oct 2026

What is the usage effect?

A hybrid contract, in Finland often called a contract with a usage effect (kulutusvaikutus), combines a fixed price with spot pricing. You pay a fixed kWh price for the contract period, but every month the usage effect is added or subtracted. It shows whether your consumption fell on the month’s expensive or cheap hours.

• The fixed part (c/kWh) stays the same for the whole contract period, usually 12 or 24 months.
• The usage effect (± c/kWh) is calculated separately for each month.
• The monthly fee (€/month) works as in other contracts.

With a hybrid, the overall spot price level does not affect your price, only the timing of your consumption within the month. That makes it more stable than a spot-price contract.

How the usage effect is calculated

The contract terms of Fortum, Oomi, KSAT and Paneliankosken Voima use the same formula:

1. Multiply the spot price of each hour or quarter-hour by your consumption in that period and add the results up.
2. Divide the sum by the month’s total consumption. This gives your consumption-weighted average price.
3. Subtract the average price of all the month’s hours or quarter-hours.

Example: the month’s average spot price is 8.00 c/kWh, but the price weighted by your consumption is 8.40 c/kWh. The usage effect is +0.40 c/kWh. If the fixed part is 9.50 c/kWh, you pay 9.90 c/kWh that month.

How large has the usage effect actually been?

Sellers usually give only a range, such as “−1…+1 c/kWh for 90 % of customers”. We calculated the real figure ourselves. Fingrid’s open data includes hourly Datahub consumption by annual consumption class, 3,806,296 metering points in total. Combined with the spot prices for the same hours, it gives the actual usage effect for every month.

The usage effect was small and positive in every size class. Finnish households use electricity in slightly more expensive hours than average, but the difference is smaller than often assumed. Small homes use the most electricity in the evening, so their figure is the highest. In electrically heated houses, heating spreads consumption across the day, and many heat their water tank at night.

Note that this is an average. Your own usage effect can be clearly lower or higher depending on when you use electricity.

Usage effect by month

The usage effect was highest in February 2026 (+0.51 c/kWh), when spot prices were high and the gap between evening and night was large. It was lowest in April 2026 (-0.15 c/kWh). The winter months decide the result for the year.

Hybrid, fixed or spot price?

In our comparison, a hybrid’s annual price includes the actual usage effect for the size class that matches your annual consumption. The cheapest contracts by home type, as a two-year average:

A hybrid is in practice a fixed-price contract with a small consumption-linked extra. It is worth it when its fixed part is more than 0.14 c/kWh lower than a comparable fixed-price contract. Spot price was cheaper still over the period, but it varies far more from month to month.

How to reduce your usage effect

For 1 Nov 2025–31 Oct 2026, the most expensive evening hours (17–21) cost 8.62 c/kWh on average and the cheapest night hours (01–05) 4.64 c/kWh. If you move 10 % of your consumption from evening to night, the usage effect drops by about 0.40 c/kWh.

• Water heater at night is often the largest single load you can shift.
• EV charging at night lowers the usage effect clearly, because charging uses a lot of energy.
• Underfloor and storage heating can be weighted towards nights and weekends.
• Washing machine and dishwasher on a timer at night or during the day.

Sauna and cooking can rarely be moved, but their share of annual consumption is usually small.

Hybrid contracts in our comparison

You can see your own annual price for every contract type in the comparison by choosing the Hybrid filter.

Frequently asked questions

What is the usage effect in a Finnish electricity contract?

The usage effect (kulutusvaikutus in Finnish) is the part of a hybrid contract (e.g. Fortum Duo, Oomi Jousto) that changes every month. It is calculated by multiplying the spot price of each hour or quarter-hour by your consumption in that period, dividing the sum by the month’s consumption and subtracting the month’s average spot price. If you use electricity in hours that are more expensive than average, the usage effect is positive and raises your price.

How large is the usage effect on average?

According to actual Datahub consumption for 1 Nov 2025–31 Oct 2026, it averaged +0.26 c/kWh for metering points under 2,000 kWh, +0.14 c/kWh for 2,000–20,000 kWh and +0.11 c/kWh for 20,000–100,000 kWh (incl. VAT). The highest monthly value was in February 2026, +0.51 c/kWh, when spot prices were high and price differences large.

Is a hybrid contract worth it?

Often, if its fixed part is clearly lower than the price of a fixed-price contract. The average usage effect is only about 0.1–0.3 c/kWh, so for example a 9.30 c/kWh hybrid (Keravan Energia Joustosähkö 24 kk) came out cheaper than the fixed-price contracts. A hybrid is not a good fit if you use a lot of electricity on weekday evenings in winter and cannot shift your consumption.

Can the usage effect be negative?

Yes. It is negative when your consumption falls on the month’s cheapest hours, such as nights and weekends. If you move 10 % of your consumption from 17–21 to 01–05, the usage effect drops by about 0.40 c/kWh on average. In spring and summer, when price differences are small, the usage effect is close to zero.

Is there a cap on the usage effect?

Most contracts have none. In Paneliankosken Voima’s käyttöWoima the usage effect is capped at ±5 c/kWh. Sellers say the usual range is about ±1–3 c/kWh a month.

Read next

• Fixed price or spot price? Which was cheaper for different home types, and in how many months spot price has won since 2021.
• Margin and monthly fee What the margin on a spot-price contract means and when the monthly fee matters more than the margin.
• Heat pump and spot price What heating costs on a spot-price contract and how much you save by shifting it to cheap hours.
• Charging an EV on spot price What charging costs at night, in the evening and during the cheapest hours of the day.
• Saving electricity at peak hours Which appliances are worth moving to cheap hours and which are not: calculated savings per appliance with actual hourly prices.
• Switching electricity contract How to switch electricity contract in Finland: termination, fixed-term contracts and moving home.

Spot prices: Ember, European Wholesale Electricity Price Data (CC-BY 4.0), original source Nord Pool. Prices include 25.5 % VAT, but not transmission fees or electricity tax. Method: How we compare. Spotted a mistake? [email protected]