55%
Adoption
Tips are consistently applied on about 55% of days (BJ Fogg, Stanford, Tiny-Habits studies).
1. What pass-through means
When the Brent price rises by 1 USD per barrel, it does not mean your monthly fuel consumption immediately becomes 1 USD more expensive. Between the crude oil wholesale market and your pump are refineries, wholesalers, station operators, taxes and market regulation. Pass-through describes the degree to which a price increase at an upstream stage is transmitted to the end consumer.
In economic research, pass-through has been studied systematically since the 1970s. The International Energy Agency (IEA), the U.S. Energy Information Administration (EIA) and the American Council for an Energy-Efficient Economy (ACEEE) publish regular studies on category-specific pass-through rates. These rates differ substantially between fuel, heating, electricity and groceries because each category has its own market structure, taxation and substitution options.
Our energy cost calculator uses empirically calibrated pass-through factors per category, multiplies them by a country factor and household size, and returns an estimate of the monthly additional costs. The model is deterministic, all values are anchored in source code (wizard.dev.js) and reviewed quarterly against current studies. A typical example: when Brent rises by 10 USD per barrel, the monthly additional costs for a four-person household in Germany amount to roughly 25 Euro, spread across fuel, heating, electricity and groceries.
Pass-through is not a constant value across all time horizons. In the short term (1 to 2 months), some categories react more strongly than in the long term (12 months) because market participants run down inventories, renegotiate supply contracts and end users adjust their behavior. We model the medium-term pass-through over a horizon of about 6 to 12 months because this is the relevant scale for household budget planning.
Where the pass-through factors come from is transparently described in our 9 data sources.
2. The formula in detail
The pass-through calculation in our calculator follows a single, transparent formula. It is implemented in code at line 5060 of wizard.dev.js and has remained structurally unchanged since the first Wizard version.
The calculation formula
Additional costs = Brent-Delta × Coefficient(category) × Country-factor × Household-size
Brent-Delta is the difference between the current Brent spot price (live from five APIs: Yahoo Q1, Yahoo Q2, Stooq, EIA, TwelveData) and a reference price. The reference is by default the rolling 90-day average, but can be manually overridden in the Wizard to model specific scenarios.
Coefficient(category) is the empirically calibrated pass-through factor per category. Fuel is at 0.7%, heating at 1.1%, electricity at 0.3% and groceries at 0.4%. These values come from aggregated studies by ADAC (DACH fuel markets), IEA (global heating markets), USDA (food pass-through) and EIA (electricity market models).
Country-factor is a correction multiplier between 0.8 and 1.2 that reflects national specifics: tax rates on energy, market concentration of providers, regulatory interventions and substitution options. Germany sits near 1.0, Switzerland at 0.9 (higher taxes dampen pass-through), the USA at 1.15 (lower taxes amplify the effect). The factors are documented in the COUNTRY_SOURCES map in the Wizard code.
Household-size is not scaled linearly. A four-person household does not consume four times what a single household consumes because many energy uses are economies of scale (a heating system runs barely more for four people than for one). We use the scaling factors of the German Federal Statistical Office and the Swiss Federal Statistical Office: 1 person = 1.0, 2 persons = 1.6, 3 persons = 1.9, 4 persons = 2.2, 5 or more persons = 2.4.
3. Pass-through factors by category
Four categories with different factors, each with an honest range. The range shows how much the values vary across studies.
Pass-through factors per 1 USD Brent increase
Fuel (0.7%): Per 1 USD Brent increase per barrel, the price at the pump rises on average by 0.7% per month. ADAC studies for the DACH region show that this factor is dampened by high fixed taxes (mineral oil, VAT and energy tax), which account for about 50 to 65% of the final price. In countries with lower taxes (USA, Poland) the factor is closer to 0.9 to 1.0%.
Heating (1.1%): The highest factor in our model because heating oil is refined directly from crude oil with minimal tax share. Gas heating reacts somewhat more weakly (about 0.8 to 0.9%) because natural gas prices follow their own market mechanisms but correlate with oil over the long term. The IEA regularly documents these pass-through rates for residential heating markets globally in its World Energy Outlook.
Electricity (0.3%): The lowest factor because the European electricity mix contains only about 5 to 10% oil-based fuels. EIA studies for the USA show similar values for states with a high share of renewables. In island systems with diesel generators (Caribbean, some Pacific states), the factor is significantly higher (1.5 to 2.5%), but this is not relevant for our primary audience.
Groceries (0.4%): Indirect pass-through via transport, packaging, fertilizers and processing. USDA studies show that a 10% increase in the Brent price leads to a Food Price Index increase of 1.0 to 1.5% with a time lag of 3 to 9 months. Over a 12-month horizon, this corresponds to about 0.4% per 1 USD Brent increase.
Choke-point map showing three oil-critical bottlenecks: Strait of Hormuz, Bab el-Mandeb, and the Suez Canal. Click a marker to see the pass-through impact.
4. Time lag per category
Not all categories react equally quickly to a Brent price shock. The time lag describes the delay between cause (Brent increase) and effect (final price increase). Our model shows the medium-term effect; other models use short-term factors.
Fuel: 0 to 4 weeks. Service stations adjust prices daily. When Brent rises today, the pump price is correspondingly higher within days to at most four weeks. The mechanism is transparent: wholesale markets for gasoline and diesel follow Brent quotations with minimal lag, and stations pass the increase along promptly.
Heating: 1 to 3 months. Heating oil wholesalers hold inventory bought at older prices. These stocks are sold off after about 4 to 8 weeks, after which new purchases at higher prices begin. With gas heating, the lag is longer due to supply contracts: many contracts have quarterly price adjustments. Electric heating follows the electricity pass-through.
Electricity: 3 to 6 months. Electricity providers have supply contracts with generators that typically run for 6 to 12 months. Price adjustments for end customers also need regulatory approval in many countries. This delays pass-through by several months. In Germany, electricity price increases often arrive with the new year when new tariffs take effect.
Groceries: 3 to 9 months. The longest lag in our model because the value chain in the food industry has many stages: fertilizer production, farming, harvest, processing, packaging, transport, wholesale, retail. FAO studies show that Brent shocks arrive in the Food Price Index with a median lag of 6 months, with significant spread from 3 to 9 months depending on product group (grain faster than meat).
Our calculator shows the long-term pass-through (12 months). This is relevant for household budget planning. Anyone who wants to know the short-term effect (1 to 3 months) must reduce the values for electricity and groceries correspondingly, because the lag shifts the effect in time but does not necessarily change the total amount.
5. Realistic-Capture in the pass-through calculation
When a saving tip theoretically saves 25% energy, we show a realistic 7.5% (30% of 25%). The reasoning is in code at lines 2143 to 2149 of wizard.dev.js.
30% instead of lab value
The Realistic-Capture formula multiplies three empirically observed effects: Adoption (how often the measure is actually applied), Persistence (how long the effect is maintained), and Rebound (how much of the efficiency gain is offset by increased usage).
65%
Persistence
The effect drops to 65% of the initial level after 6 months (ACEEE persistence studies).
−15%
Rebound
Efficiency gains are partially offset by increased usage (Stanford rebound studies).
0.55 × 0.65 × 0.85 = 0.304 → realistic 30%. Range ±20% for honest communication of uncertainty.
The range ±20% means concretely: when the model shows 30 Euro additional costs per month, 30% of households experience over 36 Euro, 30% under 24 Euro, and 40% somewhere in between. This distribution is not a theoretical confidence interval but an empirically observed distribution from IEA and ACEEE data on pass-through studies in real households.
Anyone who still wants to know the theoretical maximum effect of a saving tip (for example to see how much is maximally possible) can back-calculate it with 1 / 0.30 = 3.33. Our recommendation: stick with the realistic 30% view because it matches actual life and does not lead to frustration when saving outcomes stay below lab values.
The honest 6 limits of our methodology explain where the model ends.
6. What pass-through does NOT capture
Pratfall obligation: four honest limitations of our model. These effects exist in reality but are not in our formula.
Exchange-rate effects: Brent is traded in USD; your energy bill arrives in EUR or CHF. A Brent increase of 10 USD with simultaneous USD appreciation of 5% against EUR means an actual increase in the EUR area of effectively 15 USD equivalents. This exchange-rate component is not in our pass-through formula. We use the spot exchange rate at the time of calculation for conversion but do not model an exchange-rate forecast.
Speculation premium: In crisis scenarios (Hormuz escalation, OPEC cuts, geopolitical conflicts), traders add a risk premium to the Brent spot price. This premium can range between 5 and 25 USD per barrel and is not in our pass-through coefficients. Anyone who wants to model a crisis scenario should add the risk premium manually to the Brent price in the Wizard.
Regional subsidies and emergency measures: When Brent rises sharply, some governments intervene with subsidies (Klimabonus AT, heating cost subsidy DE) or tax cuts (short-term VAT reduction on energy). These measures can reduce the real pass-through for households by 30 to 50%. We do not model them because they are politically unpredictable and change at short notice.
Contract bindings: Anyone holding a 12-month fixed-price electricity contract feels the pass-through only at contract end. Our model shows the spot pass-through for a typical household without a fixed-price contract. With heating contracts that adjust quarterly, the effects do not arrive immediately but at the next adjustment date.
Frequently asked questions about the pass-through effect
The five questions we receive most often about the pass-through mechanism.
What happens when Brent rises by 10 USD per barrel?
For a typical four-person household in Germany with average consumption, the result per category is: Fuel about 7 Euro additional cost per month (10 USD × 0.7% × country factor), Heating 11 Euro, Electricity 3 Euro and Groceries 4 Euro. Total around 25 Euro per month. The range is ±20%, realistically between 20 and 30 Euro depending on region and provider.
Why do some categories react more strongly than others?
Heating has the highest factor (1.1%) because heating oil is refined directly from crude oil. Fuel comes second at 0.7% because taxes make up a large fixed share that does not fluctuate with the Brent price. Electricity is at 0.3% because the electricity mix in Europe is largely renewable and oil is only a marginal fuel. Groceries react at 0.4% indirectly via transport, packaging and fertilizer.
Are your coefficients current?
We review the pass-through factors quarterly against new publications from IEA, ACEEE, ADAC and USDA. When a study differs significantly from our values (e.g., by more than 0.1 percentage points), we update the code and version this methodology page. The last review took place on 2026-05-13. Sources for current values: ADAC for fuel and heating oil in the DACH region, IEA for the global heating market, USDA for groceries with time-lag studies, EIA for the electricity sector.
What about indirect pass-through effects?
Indirect effects such as inflation on services or rising rents through landlords' energy costs are not in our model. We focus on direct consumer pass-through for the four categories: fuel, heating, electricity and groceries. This covers about 60 to 70% of typical household spending on energy and food. The remaining effects are harder to quantify and strongly region dependent.
Can I recalculate the formula myself?
Yes, the formula is transparent and documented in code. You need: 1) the Brent delta in USD per barrel (current price minus reference), 2) the coefficient for your category (0.7% / 1.1% / 0.3% / 0.4%), 3) your country factor (in the wizard code under the COUNTRY_SOURCES map), 4) your household size as a multiplier. Example: 10 USD Brent increase × 0.7% fuel × 1.0 DE factor × 4 persons = 28 cents per liter of fuel additionally, scaled to monthly consumption.
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