Plan and size renewable energy systems with confidence. From solar PV and air source heat pumps to ground source systems - calculate system capacity, annual generation, and potential savings for any residential or commercial property.
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.
Select a calculator below to plan and size your renewable energy system.
Calculate the size and output of a solar photovoltaic system for your home or commercial property. Enter roof area, orientation, and pitch, choose a panel efficiency rating, and get estimated system capacity in kWp, annual generation in kWh, and indicative energy cost savings. Includes optional battery storage sizing.
Use CalculatorEstimate the required capacity of an air source heat pump (ASHP) for your property. Enter floor area, insulation standard, and number of storeys to estimate heat loss. The calculator returns recommended system size in kW, estimated annual heat output, SCOP-based running costs, and indicative savings versus gas boiler heating.
Use CalculatorCalculate the ground loop length and heat pump capacity required for a ground source heat pump (GSHP) system. Enter property floor area, insulation level, and ground type to estimate heat demand, horizontal ground collector length or borehole depth, SCOP, and annual running costs. Covers both horizontal and vertical ground array configurations.
Use CalculatorBefore you build, make sure your project has the right consents in place.
Find out whether your project needs full planning permission or qualifies as Permitted Development. Covers extensions, outbuildings, loft conversions, fencing and more - with clear rules for England.
Explore planning guidesPlain-English guidance on all Parts of the Building Regulations - from Part A (structure) and Part B (fire safety) to Part L (energy efficiency). Know what Building Control will be checking before work begins.
Explore building regsWorking on a listed building? Most works - inside and out - require Listed Building Consent. Our guides cover the consent process, acceptable materials, enforcement risks, and how to find a heritage consultant.
Explore listed building guides