Compare space, groundworks, seasonal behaviour, budget and maintenance before choosing. This guide explains the decision points without promising that one answer fits every property.

Where the heat comes from

Air source systems exchange energy with outside air. Ground source systems use buried loops or boreholes where temperatures are more stable. Both feed a correctly designed low-temperature heating system.

For where the heat comes from, ask the designer to show the property evidence, assumptions and practical consequence rather than relying on a generic rule. Record the current fuel, annual consumption if available, rooms that struggle, desired temperatures, hot-water pattern and any planned renovation. A product figure measured under stated conditions is not a household bill forecast, so comparisons should identify the design temperature, intended water temperatures, controls and enabling work. Check who owns the heat-loss calculation, emitter schedule, electrical or ground scope, commissioning and handover. Avoid selecting equipment from floor area alone or treating a grant as proof that the system suits the home. Keep the final design, settings, warranties and service record so future adjustments and fault finding start from evidence.

Practical trade-offs

Air source normally involves less ground work and suits more plots. Ground source can offer stable performance but needs land, boreholes or trenches and a larger initial project.

For practical trade-offs, ask the designer to show the property evidence, assumptions and practical consequence rather than relying on a generic rule. Record the current fuel, annual consumption if available, rooms that struggle, desired temperatures, hot-water pattern and any planned renovation. A product figure measured under stated conditions is not a household bill forecast, so comparisons should identify the design temperature, intended water temperatures, controls and enabling work. Check who owns the heat-loss calculation, emitter schedule, electrical or ground scope, commissioning and handover. Avoid selecting equipment from floor area alone or treating a grant as proof that the system suits the home. Keep the final design, settings, warranties and service record so future adjustments and fault finding start from evidence.

Choose from the property outward

Start with heat demand, available space, access and budget. Technology choice should follow the survey rather than lead it.

For choose from the property outward, ask the designer to show the property evidence, assumptions and practical consequence rather than relying on a generic rule. Record the current fuel, annual consumption if available, rooms that struggle, desired temperatures, hot-water pattern and any planned renovation. A product figure measured under stated conditions is not a household bill forecast, so comparisons should identify the design temperature, intended water temperatures, controls and enabling work. Check who owns the heat-loss calculation, emitter schedule, electrical or ground scope, commissioning and handover. Avoid selecting equipment from floor area alone or treating a grant as proof that the system suits the home. Keep the final design, settings, warranties and service record so future adjustments and fault finding start from evidence.

The practical next step

Use this information to ask better questions, then base the final decision on room-by-room heat loss, emitter output, site constraints and a written design. Renewable Heating Surrey can help turn the general principle into a property-specific assessment.