Air Purifiers for AsthmaEvidence-Based UK Guide 2026
5.4 million people in the UK have asthma. Learn how HEPA and MERV air purifiers reduce triggers by 60-95% and which specifications actually work.
UK Asthma Statistics
Don't Wait Until Symptoms Hit
Get early warnings + indoor protection before it's too late.
How Air Purifiers Help Asthma
Asthma attacks are triggered by airborne particles that inflame the airways. Air purifiers with HEPA or MERV13+ filters physically capture these triggers before you breathe them:
Triggers Removed by MERV13-16
- ✓ Dust mites and their faeces (10-40μm)
- ✓ Pollen - grass, tree, weed (10-100μm)
- ✓ Pet dander - cats, dogs (2-10μm)
- ✓ Mould spores (3-30μm)
- ✓ PM2.5 particles (fine pollution)
- ✓ Smoke particles (0.1-1μm)
Clinical Evidence
- Cochrane Review: Air filtration reduces asthma symptoms
- NICE NG80: Recommends reducing allergen exposure
- Asthma UK: Advises HEPA purifiers for trigger reduction
Recommended Specifications
Filter Rating
MERV 13-16 or HEPA H13
Captures 85-99.97% of asthma triggers
Air Changes (ACH)
5-6 per hour minimum
6-8 ACH for severe asthma
Noise Level
30-40 dB for bedrooms
PC fan builds: 30-37 dB
Room-by-Room Strategy
🛏️ Bedroom (Priority 1)
You spend 6-8 hours sleeping. A quiet PC fan build with MERV16 filter running continuously at 5-6 ACH can dramatically reduce nighttime symptoms and morning peak flow dips.
🛋️ Living Room (Priority 2)
Second-most time spent. Corsi-Rosenthal Box provides high CADR for larger rooms. Consider running on higher speed during cooking or when windows are open.
🏠 Whole-House
If you have central HVAC, upgrade to MERV13 filters in your system (check compatibility). Portable purifiers can supplement rooms where you spend most time.
Frequently Asked Questions
Do air purifiers help with asthma?
Yes, clinical evidence shows HEPA and MERV13+ air purifiers reduce asthma triggers including dust mites, pollen, pet dander, and PM2.5 by 60-95%. The Cochrane Collaboration found air filtration reduces asthma symptoms in controlled studies.
What MERV rating is best for asthma?
MERV 13 is the minimum recommended for asthma sufferers, capturing 85%+ of particles down to 0.3 microns. MERV 16 or HEPA H13 is ideal for severe asthma, capturing 95-99.97% of triggers.
How many air changes per hour for asthma?
Asthma UK and medical guidelines recommend 5-6 ACH (air changes per hour) for bedrooms and living areas. Severe asthma may benefit from 6-8 ACH. Use our calculator to determine the right CADR for your room.
Should I run an air purifier all day for asthma?
Yes, continuous operation maintains clean air. Run on low/medium during the day and reduce at night if noise is a concern. Modern MERV filters use only 10-20W, costing £20-40/year to run continuously.
Do air purifiers help with exercise-induced asthma?
Yes, air purifiers reduce airborne triggers that can exacerbate exercise-induced bronchoconstriction. Particularly helpful for home gyms or when exercising indoors during high pollution days.
Calculate Your Needs
Use our free ACH calculator to find the right CADR for your bedroom and living spaces.
ACH Calculator →Recommended Products
Luggable XL (Bedroom)
MERV16, 30-37dB, 525 m³/h
From £149
CR Box Kit (Living Room)
MERV13, 600-850 CFM
DIY from £50
Medical Disclaimer
Air purifiers are a complementary measure. Always follow your asthma action plan and take prescribed medications. Consult your GP or asthma nurse for personalised advice.
Related Guides
MERV 13 vs HEPA Filters
Which filter removes more allergens? Side-by-side comparison
DIY vs Commercial Purifiers
Performance & cost comparison: £50-100 vs £200-800
ACH Calculator
Calculate air changes per hour for your room in 10 seconds
DIY Air Purifier Guides
Build quiet, powerful purifiers from £149. Step-by-step instructions