10.45 Active PIVMVHR - Retrofits that tick priority boxes.pdf

2. Residential Indoor Air Quality (IAQ)
• We spend 90% of our time indoors. Indoor environment and quality of indoor
air we breathe is a recognised public health concern.
• IAQ is a problem in millions of British homes because of underperformance of
the predominant ventilation strategy - natural supply and mechanical
extraction. Natural ventilation is not scalable. You cant tell the wind to blow
harder or be warmer. Extractors tend to underperform (especially axials).
• Evidenced as humidity related issues including condensation, mould, radon
build-up, VOCs/odours, allergens, viral emissions etc. Often only evident
during cold months. Problem scales with occupancy size. Gets worse with
insulation improvements. Subjective control – people close
windows/ventilators due to comfort/£££. If you see condensation on your
windows your property is already suffering these issues to varying degrees.
• Negatively impacts health/wellbeing of occupants. Causes property damage.
• Problem has been rife ever since we first started double glazing in early 1970s
to save money and we first started seeing the consequences – condensation
and mould.
• Why ? Because it’s the cheapest way to comply for cost oriented builders. And
we continue to build these problems into our buildings to this day
• FACT: Humidity damp is usually misdiagnosed as structural

3. Residential IAQ and Net Zero
• To meet 2050 Net Zero emissions targets close to 28 million homes must be
retrofitted with low carbon solutions. Approx 9 out of 10 will need insulation
and EPC retrofits if we are to meet Net Zero emissions targets (PAS2035)
• If you improve insulation performance you must make a corresponding
improvement in ventilation performance or suffer the consequences.
• Insulation retrofits tend not to be accompanied by ventilation performance
improvement retrofits and performance is assumed in the vast majority.
• Air bricks and trickles often make a humidity problem worse in occupied
properties due to uncontrolled heat loss – mould in vicinity of air brick and
comfort/cost issues. Most axial fans don’t perform well after installation.
• Rate of insulation retrofits has increased in past 15 years and push for Net
Zero - double/triple glazing, loft and cavity insulation with little/no focus on
corresponding improvements to ventilation performance. This always results
in worsening humidity issues which scale/magnify with occupancy. The bigger
the occupancy the worse the problem.

4. Residential IAQ and Net Zero
• Siloed thinking around IAQ and Net Zero has created an unsustainable
scenario:
 Increased insulation in pursuit of Net Zero in millions of properties has
resulted in energy savings
BUT
 Only option to improve ventilation in virtually all of those properties to
combat resultant IAQ problems is to open windows/air bricks/trickles
resulting in energy loss and reheat costs/carbon footprint.
The only sustainable retrofit solution to the problems caused by
insulation improvements is one that replaces natural supply ventilation
and delivers scalable ventilation performance improvement without
wasting energy or causing comfort, health and wellbeing problems.
Active PIV is one such solution.

5. What is Active PIV or Active MVHR ?
• PIV and MVHR are acronyms for recognised ventilation strategies:
 PIV = Positive Input Ventilation.
 MVHR – Mechanical Ventilation with Heat Recovery.
• PIV was originally conceived in early 1970s as a retrofit strategy to
improve ventilation performance. MVHR is a specification strategy and
is usually not feasible for a retrofit (except certain flats and bungalows).
• PIV makes extant natural ventilation methods redundant and eliminates
problems caused – lack of scalability, uncontrolled heat loss, comfort
issues. Properly performing PIV retrofits also usually require upgraded
extractors and internal air transfer enabled.
• Millions of PIV and MVHR solutions have been installed over the years.
Many not done properly mainly due to competency issues.
• Done properly, PIV and MVHR are highly effective, scalable and energy
efficient whole house mechanical strategies.
• PIV comprises fragmented mechanical extraction (can comprise heat
recovery) and MVHR integrated extraction with heat recovery. PIV is
fragmented equivalent of MVHR with arguably better energy efficiency
benefits – MVHR continuous wasted energy v solar gain (loft units) and
energy loss only when boosting.
• Some argue PIV needs natural ventilators to allow air to escape. If this
were true same would apply to MVHR supply yet no mention. Also the
PIV causes interstitial condensation yet no evidence across millions of
solutions.

6. What is Active PIV or Active MVHR ?
• A PIV or MVHR system that incorporates
Photohydroionisation™ (PHI) active air
purification technology into the supply air
• Provides an extra layer of continuous
protection to indoor environments beyond
scalable dilution and displacement ventilation
and passive air treatments (Filtration, Upper
Room/Far UV, surface PCO, ionisation etc)
• Can be retrofitted into any existing or new PIV
or MVHR system

7. What is Photohydroionisation™ ?
 Imitates nature’s air cleaning processes indoors. ROS composition and concentrations similar to
outdoor air with continuous replenishment.
 Safe to breathe “ROS soup” produced from patented photocatalytic process (broad spectrum
UV/quad metal catalyst and ambient water vapour) leverages scalable mechanical supply
ventilation and reaches into every cubic cm of air and surface space.
 Effective across all 3 categories of pollutants – microbials, VOCs/gases/odours and
particulates/smoke.
 Breaks down microbials/allergens and VOCs/odours through cell lysis rendering them harmless.
Agglomerates particulates.
 Continuous treatment of viral emissions in the air and on surfaces anywhere in the indoor
space. Kills viruses at the point of transmission. Reduced risk of transmission. With HEPA and
passive UV you’ve already caught the virus by the time it reaches the filter.
 Developed in the 1990s. World’s first zero ozone active air treatment process. UL-2998
compliant. Millions of installs in over 125 countries. Proven safe and effective. No reported
safety issues anywhere.
 Reduces HAIs in healthcare. Reduces absenteeism in schools. Limits/prevents community viral
transmission.
 Creates environmental effect. Not behaviour dependent
 Creates safer healthier future proofed environments

8. Active PIV - Loft

9. Active PIV - Wall