Sources of Renewable Energy and Energy Recovery in Buildings

Definition

In an APC context, renewable energy and energy recovery in buildings refers to technologies that generate low or zero carbon energy from naturally replenished sources, or recover heat that would otherwise be wasted. Principal sources include solar PV, solar thermal, air and ground source heat pumps, biomass and district heating. Energy recovery technologies include mechanical ventilation with heat recovery (MVHR) and combined heat and power (CHP). All are relevant to compliance with the Climate Change Act 2008 (as amended 2019) and Approved Document L.

Why this matters for Sustainability

• Level 1 knowledge: you must be able to name the principal renewable energy sources and energy recovery technologies used in buildings and describe how each works.
• Surveyors advising on new development or refurbishment need to understand renewable energy technologies to interpret design proposals, assess cost implications and advise clients on which approaches are appropriate for a given site and use.
• Renewable energy installation affects BREEAM scores, EPC ratings and operational carbon, all of which influence lettability and value.

Key principles

Solar photovoltaic and solar thermal

Solar photovoltaic (PV) panels convert sunlight directly into electricity and are widely used on commercial and residential roofs. Output depends on orientation, pitch and shading; south-facing roofs optimise UK performance. Solar thermal panels heat water directly and are more efficient than PV at converting solar energy to heat, though their application is narrower.

Heat pumps

Air source heat pumps (ASHPs) and ground source heat pumps (GSHPs) extract heat from air or ground and upgrade it via a refrigerant cycle for space heating and hot water. Heat pumps typically deliver three to four units of heat per unit of electricity — expressed as the Coefficient of Performance (COP). As the grid decarbonises, their carbon advantage over gas boilers grows. GSHPs require boreholes or ground loops, limiting their use to sites with suitable conditions.

Biomass and district heating

Biomass boilers burn sustainably sourced organic material and can be near-carbon-neutral on a lifecycle basis, but produce local air quality impacts that limit their use in air quality management areas. District heating networks distribute centrally generated heat to multiple buildings via insulated pipes, simplifying building services and improving operational carbon performance as the heat source decarbonises.

MVHR and combined heat and power

Mechanical Ventilation with Heat Recovery (MVHR) recovers up to 85–90% of heat from exhaust air to pre-warm incoming fresh air, and is standard in Passivhaus design. Combined Heat and Power (CHP) generates electricity from gas and captures waste heat at combined efficiencies of 70–80%. However, gas-based CHP produces Scope 1 emissions and its carbon advantage diminishes as the grid decarbonises, limiting its long-term viability as a net zero technology.

Relevant RICS guidance and legislation

• Building Regulations Approved Document L (conservation of fuel and power) — sets minimum energy performance standards for new buildings and requires consideration of low and zero carbon technologies.
• Climate Change Act 2008 (as amended 2019) — the statutory backdrop requiring net zero by 2050, driving adoption of renewable energy across the built environment.
• Energy Performance of Buildings (England and Wales) Regulations 2012 — EPCs incorporate the contribution of renewable energy generation to a building's energy rating.
• Minimum Energy Efficiency Standards (MEES) under the Energy Act 2011 — renewables can contribute to improving EPC ratings and MEES compliance.
• BREEAM (BRE) — awards credits for renewable energy generation, low-carbon heating and energy monitoring, providing a structured framework for evaluating technology selection.

Ethics and Rules of Conduct angle

Rule 2 of the RICS Rules of Conduct (effective 2 February 2022) requires members to maintain competence. Renewable energy technology changes rapidly and surveyors must commit to staying current. Rule 3 (integrity) requires honest advice: where a technology is promoted that is unlikely to deliver its claimed performance in a specific context, the surveyor has a duty to say so, even where this contradicts the client's preferred narrative. Greenwashing is an integrity risk as well as a reputational one.

APC-style Q&As