Equivalent Warmth
In the context of insulation or thermal performance, Equivalent Warmth (EW) is a term used to compare the thermal efficiency of different materials or systems by expressing their insulating properties in a standardized way. It allows designers, engineers, or regulators to evaluate and equate the warmth provided by different building materials, layers, or assemblies to meet specific thermal performance standards or comfort requirements.
EW is often used as a comparative measure to express the thermal insulation performance of a material or system. It allows the substitution or equivalence of materials that provide the same thermal resistance or comfort level. EW can be applied to assess how well a building material maintains indoor comfort by minimizing heat loss or gain, ensuring energy efficiency. By using equivalent warmth, materials with different thicknesses, compositions, or properties can be benchmarked against each other.
EW helps when substituting insulation materials, ensuring the replacement provides the same level of thermal efficiency. It is used in building energy simulations to ensure that building envelopes meet specific thermal performance requirements. It supports adherence to building regulations, such as Part L of the UK Building Regulations, which focus on conservation of fuel and power.
It helps architects and designers ensure that spaces will be comfortable for occupants, even with variations in material selection.
EW is typically derived from the thermal resistance (R-value) of materials or systems. The R-value measures a material's resistance to heat flow (higher values indicate better insulation). EW expresses this in terms of a standardized measure of comfort or performance under specific conditions.
For example, if a building has an insulation system with an R-value of 5, an alternative material providing an R-value of 5 would have an Equivalent Warmth, ensuring no loss in performance.
[edit] Related articles on Designing Buildings.
Featured articles and news
Delivering for tenants; National Retrofit Hub
New report offers recommendations to strengthen energy efficiency standards to protect private renters.
Government consultations for the summer of 2025
A year of Labour, past and present consultations on the environment, the built environment, training and tax.
CMA competitiveness probe of major housing developers
100 million affordable housing contributions committed with further consultation published.
Homes England supports Greencore Homes
42 new build affordable sustainable homes in Oxfordshire.
Zero carbon social housing: unlocking brownfield potential
Seven ZEDpod strategies for brownfield housing success.
CIOB report; a blueprint for SDGs and the built environment
Pairing the Sustainable Development Goals with projects.
Types, tests, standards and fires relating to external cladding
Brief descriptions with an extensive list of fires for review.
Latest Build UK Building Safety Regime explainer published
Key elements in one short, now updated document.
UKGBC launch the UK Climate Resilience Roadmap
First guidance of its kind on direct climate impacts for the built environment and how it can adapt.
CLC Health, Safety and Wellbeing Strategy 2025
Launched by the Minister for Industry to look at fatalities on site, improving mental health and other issues.
One of the most impressive Victorian architects. Book review.
Common Assessment Standard now with building safety
New CAS update now includes mandatory building safety questions.
RTPI leader to become new CIOB Chief Executive Officer
Dr Victoria Hills MRTPI, FICE to take over after Caroline Gumble’s departure.
Social and affordable housing, a long term plan for delivery
The “Delivering a Decade of Renewal for Social and Affordable Housing” strategy sets out future path.
A change to adoptive architecture
Effects of global weather warming on architectural detailing, material choice and human interaction.
The proposed publicly owned and backed subsidiary of Homes England, to facilitate new homes.
How big is the problem and what can we do to mitigate the effects?
Overheating guidance and tools for building designers
A number of cool guides to help with the heat.
The UK's Modern Industrial Strategy: A 10 year plan
Previous consultation criticism, current key elements and general support with some persisting reservations.
Building Safety Regulator reforms
New roles, new staff and a new fast track service pave the way for a single construction regulator.