Direct heat interface unit
Heat Interface Units (BG 62/2015) was written by Reginald Brown and published by BSRIA in December 2015. It states: ‘A direct HIU (heat interface unit) in this guide refers to an HIU where water from the heat network is circulated through the secondary space heating circuits. There is no hydraulic separation between the heat network and secondary space heating circuits. A direct HIU for residential consumers may include a plate heat exchanger for domestic hot water. This is sometimes referred to as a “hot water plate”. Alternatively, hot water may be provided from an indirect domestic hot water cylinder.’
More details of the key features and construction of direct and indirect HIUs, including variations associated with domestic hot water production and storage, are given in Sections 7 and 8 of the guide.
--BSRIA
[edit] Related articles on Designing Buildings
- A technical guide to district heating (FB 72).
- Big growth in district heating markets - now and on the horizon.
- BSRIA articles.
- BSRIA definitions.
- BSRIA guide to heat interface units.
- Communal heating.
- District energy networks
- Domestic micro-generation.
- Heat interface unit.
- Indirect heat interface unit.
- Types of domestic boiler.
Featured articles and news
Core construction skills explained
Preparing for a career in construction.
Retrofitting for resilience with the Leicester Resilience Hub
Community-serving facilities, enhanced as support and essential services for climate-related disruptions.
Some of the articles relating to water, here to browse. Any missing?
Recognisable Gothic characters, designed to dramatically spout water away from buildings.
A case study and a warning to would-be developers
Creating four dwellings... after half a century of doing this job, why, oh why, is it so difficult?
Reform of the fire engineering profession
Fire Engineers Advisory Panel: Authoritative Statement, reactions and next steps.
Restoration and renewal of the Palace of Westminster
A complex project of cultural significance from full decant to EMI, opportunities and a potential a way forward.
Apprenticeships and the responsibility we share
Perspectives from the CIOB President as National Apprentice Week comes to a close.
The first line of defence against rain, wind and snow.
Building Safety recap January, 2026
What we missed at the end of last year, and at the start of this...
National Apprenticeship Week 2026, 9-15 Feb
Shining a light on the positive impacts for businesses, their apprentices and the wider economy alike.
Applications and benefits of acoustic flooring
From commercial to retail.
From solid to sprung and ribbed to raised.
Strengthening industry collaboration in Hong Kong
Hong Kong Institute of Construction and The Chartered Institute of Building sign Memorandum of Understanding.
A detailed description from the experts at Cornish Lime.
IHBC planning for growth with corporate plan development
Grow with the Institute by volunteering and CP25 consultation.
Connecting ambition and action for designers and specifiers.
Electrical skills gap deepens as apprenticeship starts fall despite surging demand says ECA.
Built environment bodies deepen joint action on EDI
B.E.Inclusive initiative agree next phase of joint equity, diversity and inclusion (EDI) action plan.
Recognising culture as key to sustainable economic growth
Creative UK Provocation paper: Culture as Growth Infrastructure.

























