⚖️ Independent Buyer's Guide

DIY vs Commercial Air Purifiers UKPerformance, Cost & Value Comparison 2025

Should you build a DIY Corsi-Rosenthal Box for £50-100 or buy a commercial HEPA air purifier for £200-800? We compare performance, running costs, and real-world effectiveness for UK homes.

📊 Side-by-Side Comparison

FactorDIY (Corsi-Rosenthal)Commercial HEPA
Upfront Cost£50-100£200-800
CADR (m³/h)1,020-1,445200-600 (typical)
Coverage at 5 ACH60-100m²15-50m²
Filter TypeMERV-13/14 (equivalent to H11-12)True HEPA H13/H14
Noise Level45-60dB (moderate)30-55dB (varies)
Build/Setup Time30-45 minutes5 minutes (unbox)
Annual Filter Cost£60-80 (4x filters yearly)£40-150 (brand specific)
Energy Cost/Year£55-75 @ 24W£20-60 @ 8-25W
Smart FeaturesNone (basic fan)Auto mode, WiFi, sensors
AestheticsIndustrial/DIY lookSleek, modern designs
WarrantyDIY (parts warranty only)1-5 years manufacturer

✅ Choose DIY If...

  • 💰
    Budget is Primary Concern

    Build effective air purifier for £50-100 vs £200-800 commercial

  • 📏
    Large Room Coverage Needed

    Single CR Box covers 60-100m² at 5 ACH vs multiple commercial units

  • 🔧
    You Enjoy DIY Projects

    45-minute build, no power tools required

  • 📈
    Maximum CADR Performance

    1,020-1,445 m³/h CADR beats most commercial units under £500

  • 🏫
    Schools/Offices/Large Spaces

    Cost-effective solution for classrooms (100+ UK schools using CR Boxes)

✅ Choose Commercial If...

  • 🤫
    Quiet Operation Critical

    Bedroom use, noise-sensitive environments (30-37dB possible)

  • 🎨
    Aesthetics Matter

    Sleek, modern designs blend with home decor

  • 🤖
    Want Smart Features

    Auto mode, WiFi control, air quality sensors, scheduling

  • Energy Efficiency Priority

    8-15W operation vs 20-30W DIY (£20-40/year savings)

  • 🛡️
    Warranty/Support Needed

    1-5 year warranties, customer support, certified performance

💡 Our Recommendation: Hybrid Approach

The best solution for most UK homes combines both DIY and commercial air purifiers based on room function:

🏠 Living Room/Large Spaces

Use DIY Corsi-Rosenthal Box: £50-100 cost, covers 60-100m² at 5 ACH, handles high-traffic areas efficiently.

Example: 50m² open-plan living/dining = 1x CR Box (£80) achieves 8 ACH vs 3x commercial units (£600+)

🛏️ Bedrooms

Use Quiet Commercial or PC Fan Build: £150-200, ultra-quiet 30-37dB, perfect for sleeping.

Example: 20m² bedroom = 1x PC fan HEPA kit (£180) or commercial unit (£250-400) for whisper-quiet operation

💰 Total Cost Example: 3-Bed UK Home (80m²)

All Commercial:
  • • Living room (50m²): 2x units = £500-800
  • • 2x Bedrooms: 2x units = £400-600
  • Total: £900-1,400
Hybrid Approach:
  • • Living room: 1x CR Box = £80
  • • 2x Bedrooms: 2x PC fans = £300-400
  • Total: £380-480 (60-70% savings)

🎯 Calculate Your Needs

Use our free ACH calculator to determine exactly how many air purifiers you need (DIY or commercial) based on your room dimensions and target ACH.