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 over £100 - only on MVHR filters
Order by Midday for same day dispatch
Passivhaus certified productsDiscover our range of certified airtightness and building performance solutions, designed to reduce heat loss, improve energy efficiency and create healthier, more comfortable indoor spaces.
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MVHR Filters & Parts
Replacement filters, accessories and service parts for keeping ventilation systems performing.
Specialist Insulation
Minimise thermal bridging and improve thermal efficiency across your build. Explore our selection of high-performance insulation solutions and specialised adhesives engineered for low-energy and Passivhaus construction.
Loft Hatches
Airtight, insulated loft hatches designed for high-performance homes and clean installation.
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 midday 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
Official distributor of Pro Clima, AirFi, Mitsubishi and Zehnder and other leading high-performance building brands.
Frequently Ordered
Trusted by UK Passivhaus Designers & Contractors.
30+ Years
Building performance expertise
4.9★
Customer rating
Passivhaus
Certified solutions
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
Back to 21 degrees
Wishlist
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