Every part of a conversion, three ways.

Default recommendation for nearly every build. Light, cheap, effective.

• Budget

  Manual roof vent / skylight

  MPK/generic

  2 kgest.≈ £45

  Weight sits high — raises the centre of gravity.

  Passive vent + rooflight. Cheapest airflow, no power. Every build should have one (condensation).

• Mid

  Powered roof fan (Maxxair-style)

  Maxxair/Fiamma

  3.5 kgest.≈ £250

  Weight sits high — raises the centre of gravity.

  12V reversible extractor/intake fan + rain cover. The near-universal van choice. Fit before ceiling lining.

HEAVY (~28kg) and roof-mounted — payload hit AND raised centre of gravity.

• Mid

  Truma Aventa Compact

  Truma

  27.5 kg✓ verified≈ £1,650

  Weight sits high — raises the centre of gravity.

  Lightest/quietest in class (EPP). Roof-mounted. Needs big power. ~27.5kg high on the roof — watch CoG.

• Mid

  Dometic FreshJet 2200

  Dometic

  28 kgest.≈ £1,500

  Weight sits high — raises the centre of gravity.

  Compact rooftop unit, popular Truma alternative. Similar weight/power considerations.

• Premium

  Mestic Rooftop RTA-1700L

  Mestic

  30 kgest.£1,200

  Weight sits high — raises the centre of gravity.

  Rooftop air-con (Ahoy Leisure). Mains-powered. Budget-friendlier rooftop option.

• Premium

  Truma Aventa Comfort (inverter)

  Truma

  28.7 kg✓ verified≈ £2,000

  Weight sits high — raises the centre of gravity.

  Inverter compressor, 2500W, night mode. Heavy + power-hungry — realistically needs EHU or heavy electrics.

Runs off battery, mounted low (keeps weight down). Big power draw.

• Premium

  Eberspacher Breezonic / under-bench 12V

  Eberspacher/Zeliox

  18 kgest.£2,200

  Weight sits high — raises the centre of gravity.

  12V DC air-con — runs off battery (no hook-up), mounted low (weight stays low). Needs serious LiFePO4.

~40% lighter than glass, double-glazed, integrated blind+screen. Needs timber frame-out on panel vans.

• Mid

  Dometic Seitz S4 hinged window

  Dometic Seitz

  4 kgest.≈ £250

  Premium standard: double-glazed acrylic, integrated blind + flyscreen, friction hinges. ~40% lighter than glass. Needs timber frame-out on panel vans; stands slightly proud.

• Mid

  Arctic Tern double-pane acrylic window

  Tern Overland

  4 kgest.≈ £200

  Seitz alternative — double-glazed acrylic, day/night shade + screen, swings out on struts. Light, well-liked.

Cheap, flush, stealthy, single-glazed. Cutting aperture irreversible — plan early.

• Budget

  Bonded privacy glass window

  generic OEM-style

  5 kgest.≈ £90

  Factory-style bonded glass — flush, stealthy, cheapest. Single-glazed, smashable, leak-prone if fitted badly. Cutting irreversible.

• Mid

  Bonded openable/sliding glass window

  generic

  7 kgest.≈ £150

  Sliding glass for airflow, flush look. Heavier (glass), usually no blackout. Ventilation + stealth.

Light + a bit of vent. Cutting roof irreversible — seal thoroughly.

• Budget

  MPK / basic acrylic rooflight (400x400)

  MPK

  2.5 kgest.≈ £60

  Weight sits high — raises the centre of gravity.

  Passive rooflight for light + a bit of vent. Light, cheap. Cutting roof irreversible — seal thoroughly.

• Premium

  Outbound VAN / double-glazed roof window

  Outbound/Dometic

  4 kgest.≈ £300

  Weight sits high — raises the centre of gravity.

  Premium double-glazed roof window (~30% lighter than full double-glazed). Clear, scratch-resistant, better thermal.

Adhesive/frame-out/trim/sealant. Waterproofing is critical.

• Budget

  Bonding kit / timber frame-out + trim + sealant

  Sika/generic

  2 kgest.≈ £40

  Weight sits high — raises the centre of gravity.

  Urethane adhesive + primer (glass) OR timber frame-out (Seitz on panel vans) + trim. Waterproofing critical.

Fixed low+high vents (BS EN 721) — legal safety requirement. Often overlooked.

• Budget

  Fixed habitation ventilation (BS EN 721)

  generic

  0.5 kgest.≈ £20

  Permanent low + high fixed vents — legal safety requirement (BS EN 721). Prevents CO/condensation. Not an openable window. Often overlooked.