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

07502 425158

Bristol, UK


Entries in Passivhaus (17)


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. 



Certified Passivhaus Designer

Piers has just qualified as a Certified Passivhaus Designer.  This means he is qualified to undertake Passivhaus Design and to prepare the documentation required for Passivhaus Certification. We have been undertaking Passivhaus assesments and design work for a cuouple of years now, but the AECB CarbonLite course and Passivhaus Designer qualification represent a step up in our Passivhaus credentials and we aim to increase our Passivhaus profile in 2014.


Lib Dems Refurbishment & Carbon Sequestration Proposals

The Lib Dems have published a policy document entitled Transition to Zero Carbon Britain (  On housing it is proposed that all existing buildings are refurbished to the Passivhaus refurbishment standard EnePHit.  I think they need to consider the costs and practicalities of this.  We have just done a refubishment job which cost over £100,000 for a three bedroomed detached house and despite our efforts the project fell short of the EnerPHit standard (mostly due to the large areas of north facing windows).  Let's say we would have been able to achieve EnerPHit for £100,000 the cost of achieving this across the housing stock at even a fraction of this rate would be astronomical.  

So, whilst I support the sentiment and ambition I think the Lib Dems need to think about the most cost effective ways of reaching our carbon targets.  A lesser, more achievable but still ambitious standard, needs to be combined with a low carbon grid.

Carbon sequestration is put at the centre of the policy in the first paragraph which states Our aim is that emissions in the UK should broadly be balancd by greenhouse gases sequestered in the UK.  There is absolutely no meat on this proposal though.   Natural carbon sequestration gets a brief mention in Section 8, with a focus on biochar.  There's nothing on carbon sequestration by harvested wood products or building materials.  More work required here too.


Could this be about to become the lowest energy home in Bristol?

We hope so.  We'd be interested to hear from other candidate homes.

This project is the complete energy refurbishment of a 1930s detached house.  

The refurbishment works design was led by Piers Sadler Consulting working alongside S2 Design Architects.  The house belongs to Jenny and Ceri Richards and their two children. 

The refurbishment is based on Passivhaus principles with high levels of insulation (U values <0.15W/m2K), thermally bridge free construction, airtight detailing and mechanical ventilation with heat recovery (MVHR) and Internorm triple glazed windows.  The space heating and hot water will be provided by a small gas boiler with weather compensation controls.

Key details were modelled for thermal bridging using THERM software to ensure that the treatment of thermal bridging was acceptable and the whole design was modelled using the Passivhaius spreadsheet PHPP. 

Due to orientation, espcially the large areas of north facing windows, the designs don't quite meet the Passivhaus refurbishment standard 'EnerPHit'.  The annual space heating energy usage calculated using PHPP was 34kWhr/m2/yr.  The airtightness test is yet to be done.

Construction work began in February 2013 being undertaken by Woodgate Builders.  

The photo shows the Intello+ airtightness membrane and vapour check below the joists with Kingspan K5 insulation between.  The membrane will be taped at all joints.  A further 100mm of K5 will go above the joists/rafters and 120mm of K5 external wall insulation will be applied.  

Attention to detail is critical to meet the project aims.



Expert Energy Advice for New Winery Building

We are providing advice on constriuction detailing and energy systems for a new straw bale winery near Monmouth.

We have evaluated building fabric designs using IES VE software and decided to follow a Passivhaus based approach, with high levels of insulation, thermal bridge free construction, airtightness and MVHR.  We are also looking at combining ground source heating with MVHR to achieve the cool, stable temperatures required in the building.