Renewables & Energy
Calculators

Why Accurate Renewables Calculations Matter

Renewable energy systems are a significant investment - getting the sizing right from the start is essential. An undersized solar array or heat pump will underperform against your energy needs, while an oversized system means unnecessary upfront cost that will take longer to pay back.

Our renewables calculators use UK-specific climate data, standard system performance figures, and typical property heat loss assumptions to give you realistic estimates for system sizing, annual generation, and running cost savings. These are planning tools to help you understand the opportunity before engaging an MCS-certified installer.

Whether you are a builder advising clients on low-carbon options, a developer meeting SAP targets, or a homeowner considering the switch, these calculators give you a clear starting point for any renewables project.

Key Factors in Renewables Calculations

• Roof orientation mattersSouth-facing roofs at 30-35 degrees generate around 20% more solar energy than east or west-facing pitches. North-facing arrays are rarely viable in the UK.
• Heat demand drives sizingHeat pump sizing is based on the property's design heat loss in kW. This depends on floor area, insulation levels, window areas, and the local design temperature.
• COP varies seasonallyA heat pump's coefficient of performance drops in colder weather. Annual performance is measured as the Seasonal Coefficient of Performance (SCOP) - typically 2.5-3.5 for air source systems in the UK.
• Ground loop areaHorizontal ground source systems need around 10 times the floor area of the property in land. Vertical borehole systems are more compact but significantly more expensive to install.
• Battery storage adds valueSolar PV without battery storage exports surplus generation to the grid. Battery storage increases self-consumption and improves the financial return, especially with time-of-use tariffs.