Heat Pump Running Cost Calculator

Use public EU 206/2012 Annex II Table 1 temperature-bin hours H_j. The outdoor design points are −10, +2 and −22 °C for the average, warmer and colder profiles. The heating limit is fixed at 15 °C, matching the BWP benchmark input; this is an author building assumption rather than the EU product-rating 16 °C load line. Relative load is L_j = max(15 − T_j, 0)/(15 − T_design). Heat shares w_j = H_j L_j / Σ(H_j L_j) conserve the entered annual useful space heat. The weather curve runs from 25 °C water at the heating limit to the entered design flow. The three reference weather profiles are scenarios, not postcode forecasts.

The COP approximation remains the original derived Carnot temperature-lift model: COP_j = clamp[COP_ref × (T_water,j + 273.15)/308.15 × 28/(T_water,j − T_j) × f_perf, 1, 8]. The 25 °C endpoint, 1–8 bounds and f_perf = 0.90 default are declared assumptions, not coefficients fitted to BWP outputs. Estimated compressor/fan seasonal space-heating COP = 1/Σ(w_j/COP_j). It is not a certified EN 14825 SCOP.

Numerical BWP benchmark, downloaded 25 October 2026. Attached reports s9–s12 use Vaillant aroTHERM plus VWL 75/6 A 230V (S2), BWP model 5058; COP A−7/A2/A7 at W35 = 2.80/4.10/4.80; 15 °C heating limit; −10 °C design outdoor; monovalent; one unit; no hot water or supplementary heater. The reference reports follow VDI 4650 Blatt 1:2024-02. No standard tables are reproduced.

The comparison uses generator-outlet space heat over compressor/fan electricity, with Q_water = 0, resistance heat = 0 and additional auxiliaries = 0. The model uses the design outlet temperature as a sink proxy; the benchmark's 7 K return-temperature spread is an implicit boundary condition, not an independently modelled variable. EU bin weather and VDI weighting differ. The observed bias is reported without correcting the COP coefficients. Reference checks accept a declared ±15% screening band for this four-case envelope only; this is not a general uncertainty guarantee.

Whole-system electricity = Q_space(1 − f_res)/SCOP_on + Q_space f_res + Q_water/COP_water + E_aux. Whole-system JAZ is total useful heat divided by this electricity. Supplied-JAZ mode replaces this entire expression, avoiding duplicate backup and auxiliary charges.

Heat-pump cost = electricity × effective customer energy price + fixed/service costs − allocated customer Module 1 credit. Separate §14a calculation requires confirmed contractual pass-through. Module 2 assumes the full 60% reduction of the undiscounted network energy charge reaches the customer. Module 1 is the amount actually credited, limited by eligible network charges and allocated once. Unconfirmed or partial pass-through uses a final quoted customer tariff instead.

Selected fuel input energy = useful heat / seasonal efficiency. Gas uses gross-basis efficiency and billed kWh. EBeV 2030 Annex 2 Part 4 (s5 p18) gives 3.2508 GJ/MWh × 0.0558 t/GJ = 0.18139464 kg CO₂ per billed gross-calorific kWh. Carbon cost receives VAT and is added only to a CO₂-excluded quote.

Light heating oil and kerosene use net-basis efficiency. EBeV 2030 Annex 2 Part 4 (s5 p18) gives densities 0.845 and 0.8 kg/l respectively, net calorific value 42.8 MJ/kg for both, and direct CO₂ factors 0.074 and 0.0733 t/GJ respectively. Net energy per litre = density × calorific value, explicitly converted into kWh/l; annual litres = purchased net kWh / kWh per litre. These give about 10.046 and 9.511 kWh/l, and 2.676 and 2.510 kg CO₂/l. Annual fuel cost = number of billed kWh or litres × quoted price + selected service allowance + any additional carbon charge. Dividing physical quantities by one kWh, litre or metric tonne gives dimensionless billing counts; currency strings are display labels.

Carbon-period selection changes the interpretation of the editable certificate price. 2026 uses the statutory auction corridor; 2027 is the dated cabinet-corridor scenario (€55–65/t); 2028+ uses an entered ETS2 market-price scenario. None is a forecast of retail energy prices. Local inclusive-quote mode sets the allocated German carbon price to zero. Changing a carbon price does not alter a CO₂-inclusive fuel quote; to model a carbon-driven price change, enter a carbon-excluded base quote and select the surcharge. A price is never added twice.

The unconstrained break-even electricity price is tested against €0.01–1.00/kWh, the Module 2 network-component floor, and the nonnegative allocated-bill constraint before display. Invalid chart points are deliberate gaps wherever allocated Module 1 credit exceeds energy plus fixed costs; those negative bills are not plotted.

Net-calorific (Hi) efficiency may exceed 1.00 because recovered condensation heat is absent from the Hi denominator. Buderus Logano plus, attached s16 pp18–19, illustrates standard utilization ratings up to 104% Hi versus 98% Hs. Those ratings establish the energy-basis distinction; they are not installed seasonal measurements.

Heat demand remains as entered when climate or efficiency changes. The reference climate distributes annual heat across bins; it does not size equipment or calculate a capacity deficit. The 15 °C heating limit and linear water-temperature curve assume weather compensation. Resistance heat share, hot-water COP and extra auxiliaries are supplied scenarios. COP_ref alone cannot describe every manufacturer's performance curve.

Use matching heat and electricity boundaries. Useful heat includes downstream distribution and storage losses to be covered at the generator outlet. Only auxiliaries outside the tested COP boundary are added. A supplied system JAZ includes all entered heat, backup and electricity. Boiler efficiency uses billed gross-calorific kWh; gas-boiler auxiliary electricity belongs in the gas fixed/service allowance.

All currency is EUR; the metric/US switch changes physical display units, not currencies. Local foreign-currency quotes must first be converted consistently into EUR. Prices and credits include VAT except the carbon certificate price, to which the entered VAT multiplier applies. Electricity €0.25/kWh is a historical May 2025 worked-example price. Gas €0.10/kWh, heat-pump service/fixed €200/year and gas service/fixed €300/year are illustrative assumptions set 2026-10-25. Module 1 €175/year is a BWP 2026 network example, not a guaranteed customer saving. Enter only the amount actually passed to you under your contract. Module 2 requires confirmation that its full network energy-charge reduction is passed through in addition to the entered price. Partial or unknown pass-through must use quoted-tariff mode.

Light heating oil and kerosene use EBeV 2030 Annex 2 Part 4 standard net fuel properties, not a fuel supplier's batch analysis. Liquid-heater net-basis efficiency 0.85, delivered price €1.10/litre and annual service/fixed allowance €300 are illustrative scenarios set 2026-10-25, shared by the two liquid presets. Change them for the appliance and offer. A room-only kerosene heater does not supply the entered hot-water demand: use zero hot water unless a matching kerosene system covers it. Equal useful heat assumes equal heated area and comfort; required ventilation losses must already be in that demand.

Native temperature editing stores one flow temperature in °C and converts °F or K with the offset. German carbon pricing and §14a are jurisdiction-specific. For Japan or another local market, select the local inclusive-quote option and enter all prices in EUR at a common exchange-rate date. This mode assigns no German carbon charge; it does not remove taxes already included in a local quote.

Liquid efficiency permits 0.40–1.07 on the net-calorific basis. The 1.07 screening ceiling is an author-selected envelope rounded upward from the illustrative gross/net energy ratio 104/98 ≈ 1.061 implied by Buderus's paired ratings; it is not a manufacturer seasonal-efficiency claim or a universal fuel-property limit. Enter actual seasonal efficiency and losses for your system. All carbon-period options except Other country represent German cases, including the future German ETS2 scenario. Other country requires a final quoted electricity tariff and excludes both German §14a modules.

Rules and prices snapshot: 25 October 2026. The approximation is for preliminary air-to-water cost screening, not equipment selection or a certified JAZ. The numerical benchmark covers one named model, 35–60 °C design flow, a 7 K flow/return spread, 15 °C heating limit, average reference climate with −10 °C design outdoor, COP_ref 4.8, and f_perf 0.90. Its 8–14% low bias versus BWP and the ±15% comparison band apply to those four cases only. Other COP curves, warmer/colder climates, different hydraulic spreads and hot-water performance are not validated by those cases. Use the model-specific BWP result or a measured system JAZ for a decision. Check against the standard in force for any formal EN 14825 SCOP or VDI 4650 determination.

The input envelope permits design flow 35–60 °C, COP_ref 2–6, seasonal correction 0.5–1.0, resistance heat fraction 0–0.5 and hot-water COP 1–6; these bounds prevent numerical misuse and do not extend the benchmark's accuracy claim. Frost, refrigerant properties, capacity modulation, detailed hydraulics and local weather are not resolved.

German §14a eligibility and supplier pass-through are separate questions. BNetzA guidance states that the network determination does not itself oblige suppliers to pass reductions to customers under existing contracts. Both separate Module 1 and Module 2 calculations require confirmation from the supply contract. Module 1 uses the credit actually passed to the customer, allocated once. Module 2 assumes full pass-through of the 60% network energy-charge reduction and confirmed separate metering. If unconfirmed, partial, or already included, enter the final customer price in quoted-tariff mode. Module 3 requires a defensible time-weighted final quote and is outside this flat-price model.

The break-even price is shown only if all selected-tariff price constraints can be met. Negative mathematical bills arising from overallocated credit are omitted from the JAZ curve. Installation and electrical work belong to qualified persons.

Dated carbon scenarios, checked 25 October 2026. BEHG §10 specifies a 2026 €55–65/t auction corridor, not a universal cap on supplier procurement costs or retail carbon pass-through. €60/t is a scenario midpoint. The cabinet decision of 12 August 2026 proposed extending that corridor to 2027 (BMUKN s13). The Bundestag reports passing the amended bill on 15 October 2026 (s14). The 2027 option retains the dated proposal as a scenario; this tool does not assert completed enactment or entry into force. EU ETS2 operation is scheduled from 2028, delayed from 2027 (European Commission s15). Any entered 2028+ price is a sensitivity scenario, not a forecast or statutory ceiling; the reserve's price trigger is not a hard price cap. The VAT multiplier and actual supplier pass-through remain user assumptions.

Oil and kerosene properties are statutory standard proxies; seasonal efficiency and delivered prices are appliance- and location-dependent. Net-basis efficiency above 1.00 is allowed for condensation within the 0.40–1.07 input envelope; do not use a catalogue standard utilization rating as evidence of actual seasonal performance. Direct emissions exclude upstream fuel production. Kerosene room-heater comparison requires the same heated area and comfort boundary, with ventilation heat losses included in useful heat; set hot-water heat to zero unless the comparison system actually provides it. Other country mode requires Quoted tariff and excludes both German carbon charges and §14a discounts, including for Japan. GModG/GEG compliance, subsidies, capital costs, lifetime economics, PV and future price forecasts are excluded.