Airtightness
Membranes, tapes, adhesives and sealants for robust airtight detailing on low-energy builds.
High-Performance Building Supplies for Low-Energy Builds
Industry-leading airtightness membranes, tapes, adhesives, and replacement MVHR filters.
Free next day delivery on orders over £100Order by 2pm for same day dispatchPassivhaus certified products
Explore our complete range of certified building envelope solutions. Purpose-built to deliver continuous airtightness, optimal indoor air quality, and long-term efficiency.
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MVHR Filters & Parts
Replacement filters, accessories and service parts for keeping ventilation systems performing.
Specialist Insulation
Thermal bridge solutions and specialist insulation products for better building envelopes.
Loft Hatches
Airtight, insulated loft hatches designed for high-performance homes and clean installation.
Sale
Limited offers on trusted supplies for airtightness, MVHR maintenance and efficient builds.
Whole-House Systems
Get engineered MVHR designs and airtightness specs tailored to your Passivhaus or low-energy project.
The 21° difference.
Passivhaus certified
Premium building envelope products independently tested and certified.
Next-day site delivery
Order before 2 PM for rapid dispatch directly to your job site across the UK.
Engineering expertise
Backed by our in-house technical team for system design, specification, and advice.
Official UK distributor
Authorized distributor for Pro Clima, PAUL, Brink, and high-performance brands.
Trusted by UK Passivhaus Designers & Contractors.
98%
On-time delivery rate
2,500
Sites supplied
100%
Certified performance
Need a full MVHR design or airtightness specification?
Our engineering team designs and reviews MVHR ventilation and airtightness systems to ensure Passivhaus compliance and optimal indoor air quality.
Needed replacement MVHR filters and Solitex membrane delivered directly to site on short notice. Arrived next morning as promised.
Gareth W
Passivhaus Builder
We use 21° for all our Passivhaus builds. The technical team knows their stuff inside out, and the products consistently pass air pressure tests first time.
Eleanor Vance
Timber Frame Specialist