Passivhaus Consultant and Designer.  Very Low Energy Buildings.  Domestic and non-domestic.  New build and refurbishment. 

07502 425158

Bristol, UK



An air test was undertaken by John from Building Analysis and Testing yesterday at 101 High Kingsdown.  This is a 1970s refurbishment.  We were pleased with the air permeability of 2.1m3/m2/hr @50pa which beat the target of 3.  The main areas of leakage were between the ground and first floors and partition walls where we knew we had to make compromises due to access.  The result is compatible with the installed Paul Novus MVHR from the Green Building Store.



New projects gallery

We have restructured the website a little to make it easier to view projects at a glance.  The projects tab on the right now links to a gallery page which shows pictures and descriptions of some key projects.  We will keep adding more.


10 things to consider when choosing between MVHR quotes

  1. Price
  2. Efficiency
  3. Specific fan power
  4. Ducting type
  5. Controls
  6. Frost protection
  7. Cold side duct insulation and airtightness
  8. Cost of filters
  9. Noise
  10. Commissioning

Look out for re-heaters too - they are a sign of inefficiency as the supply air needs to be heated on a cold day due to low delivery temperatiures from the heat exchanger.

We recently reviewed two quotes for a job covering most of these 10 and the results are below:

In this case System 1 was a Paul Focus 200.  This was more expensive but we recommended it and it has now been supplied by green Building Store and installed by Greenheart Sustainable Construction.


Refurbishment Works at High Kingsdown

We have been advising on an energy efficiency refurbishment of a 1970s house in High Kingsdown, Bristol. The house is to be a student let and one of the drivers for the refurbishment was severe condensation and mould which had developed during previous occupancy.  The refurbishment strategy included:

  • cavity wall insulation, internal wall and loft insulation
  • new triple glazed windows with internal blinds
  • air tightness strategy
  • new condensing gas boiler
  • mechanical ventilation with heat recovery (MVHR)

The design and implementation has been undertaken by Studio 2 a collaboration between Piers Sadler Consulting, S2 Design Architects and Greenheart Sustainable Construction all based at Studio 2, St Andrews Road, Montpelier, Bristol.

The construction work is well under way with insulation, airtightness and MVHR installation almost complete. Piers Sadler Consulting has been advising on some of the complex detailing for air tightness and thermal bridge avoidance as well as on MVHR design and procurement.

Paul Focus 200 with insulated supply and exhaust ducts and frost protection shown below:



Four Oaks Passivhaus Submitted for Planning


We have been assisting a private client and local architect MJW Architects develop designs for a new build Passivhaus in Nailsea, North Somerset.  The building is a detached two storey replacement house.  We have advised on wide ranging aspects of the design including location on site, orientation, layout, form, fenestration, construction and services. The building has been modelled in PHPP and the results used to advise on design options, particularly shading of the large areas of south facing windows, which has been achieved with sliding shutter doors and brise soleil.

Importantly, with the imminent winding down of the Code for Sustainable Homes we have asked the planning department at North Somerset Council to consider Passivhaus as an alternative to the current requirement of Code level 3 for all dwellings.  Initial responses suggest that this is viewed positively.

We will publish the outcome and further project developments when the planning application is determined.