Figures are reproduced from the supplied updated pamphlets. Displayed bill totals and savings are retained as printed and may differ slightly when subtracted. Prices, specifications, grant eligibility and savings are subject to confirmation; actual results vary by property, tariff, weather, roof orientation and usage. Battery headings in the pamphlets use kW while their examples use kWh; final power and capacity will be confirmed in your quotation.
Explore the consumption calculator +
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Consumption calculator
Estimate annual energy use for this package. Start with your bills.
Heating gaskWh / year
Grid electricitykWh / year
Illustrative model for a home currently using gas heating. Excludes other gas appliances. Electricity input excludes electric heating. Assumes unchanged useful heat demand; solar use is capped at electricity demand. Battery shifting, charging losses, auxiliary loads, tariffs and savings are not modelled. Heating and solar defaults use the updated pamphlet assumptions. Other household electricity starts at an editable 3,000 kWh/year; replace it with your own bill figure. This consumption estimate does not calculate the pamphlet’s financial savings.
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Consumption & savings calculator
Smart boiler + 3 kWh battery. Enter your combined monthly gas and electricity bill to estimate your energy use and savings.
Your estimated results
Annual savingper year
Monthly savingmonthly average
New monthly billgas and electricity
Annual energy consumption
| Energy bought | Current estimate | With this package |
|---|
| Gas (kWh) | | |
|---|
| Grid electricity (kWh) | | |
|---|
| Total energy (kWh) | | |
|---|
Gas reduced: kWh/year. Grid electricity increases by kWh/year because of battery charging losses. Total energy reduced: kWh/year.
Annual bills
- Current combined bill
- New gas bill
- New electricity bill
- New combined bill
How the battery changes your electricity use +
- Battery electricity supplied to your home
- kWh/year
- Night-rate electricity for charging
- kWh/year
- Remaining day-rate electricity
- kWh/year
- Useful heat demand
- kWh/year
View calculation assumptions +
- Gas: 7.2765p/kWh; electricity day rate: 25.3365p/kWh; night rate: 8.4p/kWh.
- Annual standing charges: £106.08 gas and £217.95 electricity (£324.03 combined).
- After standing charges, your bill is split using a reference household of 10,000 kWh gas and 2,900 kWh electricity per year. Actual household proportions vary.
- Existing boiler efficiency: 70%; Terra boiler efficiency: 90%. All gas use is assumed to be for heating and hot water.
- Battery output: up to 3 kWh per day for 365 days, capped at your estimated electricity use. Round-trip efficiency: 90%.
- All battery charging uses the night rate and replaces day-rate consumption. The PDF's 8.4p night rate is inferred, so confirm your actual day and night tariff before relying on the estimate.
Illustrative estimate using the supplied boiler-and-battery calculation model and fixed tariffs, not a guaranteed saving or a live tariff quote. Battery charging losses can increase grid electricity use while cheaper night charging reduces cost. Results use unrounded calculations and are displayed to two decimal places; displayed totals may differ by a penny.
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Consumption & savings calculator
Smart boiler + two 470W solar panels. Enter your combined monthly gas and electricity bill to estimate your energy use and savings.
Your estimated results
Annual savingper year
Monthly savingmonthly average
New monthly billgas and electricity
Annual energy consumption
| Energy bought | Current estimate | With this package |
|---|
| Gas (kWh) | | |
|---|
| Grid electricity (kWh) | | |
|---|
| Total energy (kWh) | | |
|---|
Gas reduced: kWh/year. Grid electricity reduced: kWh/year. Total energy reduced: kWh/year.
Annual bills
- Current combined bill
- New gas bill
- New electricity bill
- New combined bill
How solar changes your electricity use +
- Solar electricity generated
- kWh/year
- Solar electricity used in your home
- kWh/year
- Surplus solar (no export income included)
- kWh/year
- Useful heat demand
- kWh/year
View calculation assumptions +
- Gas: 7.2765p/kWh; electricity: 25.3365p/kWh. There is no battery in this package.
- Annual standing charges: £106.08 gas and £217.95 electricity (£324.03 combined).
- After standing charges, your bill is split using a reference household of 10,000 kWh gas and 2,900 kWh electricity per year. Actual household proportions vary.
- Existing boiler efficiency: 70%; Terra boiler efficiency: 90%. All gas use is assumed to be for heating and hot water.
- Two 470W panels (0.94 kW) with an assumed yield of 900 kWh per kW per year generate 846 kWh/year. Actual yield depends on location, roof orientation, tilt and shading.
- The model assumes 100% solar self-use, capped at estimated household electricity demand. Without a battery, actual self-use may be lower. At 50% self-use, the PDF’s reference annual saving falls to £268.87. No income is included for surplus electricity exported.
Illustrative estimate using the supplied boiler-and-solar calculation model and fixed tariffs, not a guaranteed saving or a live tariff quote. Assumes 100% solar self-use up to household demand, with no export income; actual savings depend on when electricity is used and how much your panels generate. Results use unrounded calculations and are displayed to two decimal places; displayed totals may differ by a penny.
A CLEARER PICTURE
Consumption & savings calculator
Smart boiler + 3 kWh battery + two 470W solar panels. Enter your combined monthly gas and electricity bill to estimate your energy use and savings.
Your estimated results
Annual savingper year
Monthly savingmonthly average
New monthly billgas and electricity
Annual energy consumption
| Energy bought | Current estimate | With this package |
|---|
| Gas (kWh) | | |
|---|
| Grid electricity (kWh) | | |
|---|
| Total energy (kWh) | | |
|---|
Gas reduced: kWh/year. Grid electricity reduced: kWh/year. Total energy reduced: kWh/year.
Annual bills
- Current combined bill
- New gas bill
- New electricity bill
- New combined bill
How solar and the battery work together +
- Solar electricity generated
- kWh/year
- Solar electricity used in your home
- kWh/year
- Surplus solar (no export income included)
- kWh/year
- Electricity needed after solar
- kWh/year
- Battery electricity supplied to your home
- kWh/year
- Night-rate electricity for battery charging
- kWh/year
- Remaining day-rate electricity
- kWh/year
- Useful heat demand
- kWh/year
View calculation assumptions +
- Gas: 7.2765p/kWh; electricity day rate: 25.3365p/kWh; night rate: 8.4p/kWh. The night rate is inferred in the supplied model; confirm your actual day and night tariff.
- Annual standing charges: £106.08 gas and £217.95 electricity (£324.03 combined).
- After standing charges, your bill is split using a reference household of 10,000 kWh gas and 2,900 kWh electricity per year. Actual household proportions vary.
- Existing boiler efficiency: 70%; Terra boiler efficiency: 90%. All gas use is assumed to be for heating and hot water.
- Two 470W panels (0.94 kW) with an assumed yield of 900 kWh per kW per year generate 846 kWh/year. Actual yield depends on location, roof orientation, tilt and shading.
- The model assumes 100% solar self-use, capped at estimated household electricity demand. Actual self-use may be lower: at 50%, the PDF’s reference annual saving falls to £444.11. No income is included for surplus electricity exported.
- Solar is used first. The battery supplies up to 3 kWh per day for 365 days, capped at electricity demand remaining after solar. Round-trip efficiency is 90%.
- The battery charges only from the grid at night and replaces day-rate electricity. Charging from surplus solar is not included in this model.
Illustrative estimate using the supplied boiler, battery and solar calculation model and fixed tariffs, not a guaranteed saving or a live tariff quote. Assumes 100% solar self-use up to household demand, with no export income; solar is used before the battery, which charges at night from the grid. Actual savings depend on your tariffs, usage, solar generation and system operation. Results use unrounded calculations and are displayed to two decimal places; displayed totals may differ by a penny.
A CLEARER PICTURE
Consumption & savings calculator
Heat pump + two 470W solar panels. Enter your combined monthly gas and electricity bill to estimate your energy use and savings.
Your estimated results
Annual savingper year
Monthly savingmonthly average
New monthly billelectricity; gas disconnected
Annual energy consumption
| Energy bought | Current estimate | With this package |
|---|
| Gas (kWh) | | |
|---|
| Grid electricity (kWh) | | |
|---|
| Total energy (kWh) | | |
|---|
Gas reduced: kWh/year. Change in grid electricity: kWh/year (positive = increase; negative = reduction). Total energy reduced: kWh/year.
Annual bills
- Current combined bill
- New gas bill
- New electricity bill
- New combined bill
How the heat pump and solar change your electricity use +
- Heat pump electricity needed
- kWh/year
- Home electricity before solar
- kWh/year
- Solar electricity generated
- kWh/year
- Solar electricity used in your home
- kWh/year
- Surplus solar (no export income included)
- kWh/year
- Useful heat demand
- kWh/year
View calculation assumptions +
- Gas: 7.2765p/kWh for the current bill; electricity: 25.3365p/kWh. There is no battery in this package.
- Current annual standing charges: £106.08 gas and £217.95 electricity (£324.03 combined). The new bill keeps the electricity standing charge but assumes the gas connection is removed. If gas is retained, the reference annual saving falls to £350.81.
- After standing charges, your bill is split using a reference household of 10,000 kWh gas and 2,900 kWh electricity per year. Actual household proportions vary.
- Existing boiler efficiency: 70%. Heat pump COP: 3.0 for heating and hot water throughout the year; actual seasonal efficiency varies. All current gas use is assumed to be for heating and hot water, with no gas cooking or other gas appliances.
- Two 470W panels (0.94 kW) with an assumed yield of 900 kWh per kW per year generate 846 kWh/year. Actual yield depends on location, roof orientation, tilt and shading.
- The model assumes 100% solar self-use, capped at total annual home electricity demand including the heat pump. Winter heating demand and summer solar generation may not coincide, so actual self-use may be lower. At 50% self-use, the PDF’s reference annual saving falls to £349.72. No export income is included.
Illustrative estimate using the supplied heat-pump-and-solar calculation model and fixed tariffs, not a guaranteed saving or a live tariff quote. Assumes gas is disconnected and 100% solar self-use up to annual home demand. Actual savings depend on heat pump performance, electricity-use timing and solar generation. Calculations stay unrounded until display; displayed totals may differ by a penny.
A CLEARER PICTURE
Consumption & savings calculator
Heat pump + 3 kWh battery. Enter your combined monthly gas and electricity bill to estimate your energy use and savings.
Your estimated results
Annual savingper year
Monthly savingmonthly average
New monthly billelectricity; gas disconnected
Annual energy consumption
| Energy bought | Current estimate | With this package |
|---|
| Gas (kWh) | | |
|---|
| Grid electricity (kWh) | | |
|---|
| Total energy (kWh) | | |
|---|
Gas reduced: kWh/year. Grid electricity increases by kWh/year because heating now uses electricity and battery charging includes losses. Total energy reduced: kWh/year.
Annual bills
- Current combined bill
- New gas bill
- New electricity bill
- New combined bill
How the heat pump and battery change your electricity use +
- Heat pump electricity needed
- kWh/year
- Home electricity before battery charging losses
- kWh/year
- Battery electricity supplied to your home
- kWh/year
- Night-rate electricity for charging
- kWh/year
- Remaining day-rate electricity
- kWh/year
- Useful heat demand
- kWh/year
View calculation assumptions +
- Gas: 7.2765p/kWh; electricity day rate: 25.3365p/kWh; night rate: 8.4p/kWh.
- Current annual standing charges: £106.08 gas and £217.95 electricity (£324.03 combined). The new bill retains the electricity standing charge but assumes gas is disconnected. Keeping the gas connection lowers the reference annual saving to £311.70.
- After standing charges, your bill is split using a reference household of 10,000 kWh gas and 2,900 kWh electricity per year. Actual household proportions vary.
- Existing boiler efficiency: 70%; heat pump COP: 3.0 for heating and hot water throughout the year. Actual seasonal efficiency depends on the model, flow temperature, insulation and weather. All current gas is assumed to be for heating and hot water, with no gas cooking.
- Battery output: up to 3 kWh per day for 365 days, capped at total estimated household and heat pump electricity use. Round-trip efficiency: 90%.
- All battery charging uses the night rate and replaces day-rate consumption. The PDF's 8.4p night rate is inferred, so confirm your actual day and night tariff before relying on the estimate. A higher day rate on a time-of-use tariff would reduce the saving.
Illustrative estimate using the supplied heat-pump-and-battery calculation model and fixed tariffs, not a guaranteed saving or a live tariff quote. Assumes gas disconnection, heat pump COP 3.0 and daily night-rate battery charging. Grid electricity increases because heating moves to electricity and charging includes losses; the battery shifts part of the cost to the cheaper night rate. Results use unrounded calculations and are displayed to two decimal places; displayed totals may differ by a penny.
A CLEARER PICTURE
Consumption & savings calculator
Heat pump + 3 kWh battery + two 470W solar panels. Enter your combined monthly gas and electricity bill to estimate your energy use and savings.
Your estimated results
Annual savingper year
Monthly savingmonthly average
New monthly billelectricity; gas disconnected
Annual energy consumption
| Energy bought | Current estimate | With this package |
|---|
| Gas (kWh) | | |
|---|
| Grid electricity (kWh) | | |
|---|
| Total energy (kWh) | | |
|---|
Gas reduced: kWh/year. Change in grid electricity: kWh/year (positive = increase; negative = reduction). Total energy reduced: kWh/year.
Annual bills
- Current combined bill
- New gas bill
- New electricity bill
- New combined bill
How the heat pump, solar and battery work together +
- Heat pump electricity needed
- kWh/year
- Home electricity before solar
- kWh/year
- Solar electricity generated
- kWh/year
- Solar electricity used in your home
- kWh/year
- Surplus solar (no export income included)
- kWh/year
- Electricity needed after solar
- kWh/year
- Battery electricity supplied to your home
- kWh/year
- Night-rate electricity for battery charging
- kWh/year
- Remaining day-rate electricity
- kWh/year
- Useful heat demand
- kWh/year
View calculation assumptions +
- Gas: 7.2765p/kWh; electricity day rate: 25.3365p/kWh; night rate: 8.4p/kWh. The night rate is inferred in the supplied model; confirm your actual day and night tariff. A higher day rate on a time-of-use tariff would reduce savings.
- Current annual standing charges: £106.08 gas and £217.95 electricity (£324.03 combined). The new bill retains the electricity standing charge but assumes gas is disconnected. Keeping the gas connection lowers the reference annual saving to £526.05.
- After standing charges, your bill is split using a reference household of 10,000 kWh gas and 2,900 kWh electricity per year. Actual household proportions vary.
- Existing boiler efficiency: 70%; heat pump COP: 3.0 for heating and hot water throughout the year. Actual seasonal efficiency depends on the model, flow temperature, insulation and weather. All current gas is assumed to be for heating and hot water, with no gas cooking.
- Two 470W panels (0.94 kW) with an assumed yield of 900 kWh per kW per year generate 846 kWh/year. Actual yield depends on location, roof orientation, tilt and shading.
- The model assumes 100% solar self-use, capped at estimated household and heat pump electricity demand. Solar peaks in summer while heating demand peaks in winter, so actual self-use may be lower: at 50%, the PDF’s reference annual saving falls to £524.95. No income is included for surplus electricity exported.
- Solar is used first. The battery supplies up to 3 kWh per day for 365 days, capped at electricity demand remaining after solar. Round-trip efficiency is 90%.
- The battery charges only from the grid at night and replaces day-rate electricity. Charging from surplus solar is not included in this model.
Illustrative estimate using the supplied heat pump, battery and solar calculation model and fixed tariffs, not a guaranteed saving or a live tariff quote. Assumes gas disconnection, heat pump COP 3.0 and 100% solar self-use up to total annual home demand, with no export income; solar is used before the battery, which charges at night from the grid. Actual savings depend on your tariffs, usage, solar generation and system operation. Results use unrounded calculations and are displayed to two decimal places; displayed totals may differ by a penny.
