Passivhaus

Passivhaus is the most widely recognised international energy and comfort standard for buildings, with a rigorous assessment and commissioning process. It puts occupant wellbeing first, with steady indoor temperatures and a constant supply of fresh air. A Passivhaus building needs very little energy to heat in the first place, because it is well insulated and carefully sealed against draughts.

Construction methods vary, but Passivhaus buildings usually share some common features:

– far greater insulation than typical UK properties
– triple glazing, with insulated frames
– exceptional airtightness, no more than 0.6 air changes per hour at 50 Pascals
– mechanical ventilation with heat recovery

I use the Passive House Planning Package (PHPP) and designPH for SketchUp to assess and test design options, whether or not the building is to be certified. This makes it easy to compare energy performance against cost and appearance across a range of options, and to see whether one design concept outperforms another. It removes guesswork and gives my clients confidence in their decisions.

If you are considering a sustainable build project, please get in touch. I can guide you through the process from start to finish, or work alongside your architect to deliver the standard you need.

Retrofit

Retrofitting means making improvements to an existing property so that it uses less energy. This cuts energy bills and carbon emissions, and makes the home more comfortable.

I believe in a fabric first approach, focusing on airtightness, insulation and reducing thermal bridging. These measures improve the performance of the building itself, rather than relying on add-on technologies to make up for its weaknesses. Fabric upgrades can be more challenging and sometimes more disruptive, but they usually offer better long-term value. Reducing the energy a building needs also makes any future renewable technology, such as solar panels, more effective. In most cases, investing in the fabric first gives a better return than systems that may have a shorter lifespan or depend on sunlight or grid tariffs.

There are few retrofit standards available. The Passivhaus retrofit standard, EnerPHit, is a brilliant aspiration, but it can be hard to reach in many UK homes. The AECB CarbonLite Retrofit Standard offers a more practical route. It can be met in one go, or step by step, starting with a heat pump, good ventilation and better airtightness, with a plan in place for the later stages.

What sets the AECB standard apart is that it recognises every home is different. It requires the risks of retrofit, such as moisture and condensation, to be assessed and managed so that improvements do not cause new problems. Using PHPP as a design tool, the standard helps make sure a retrofit delivers the comfort and energy savings it promises, avoiding the “performance gap” seen in so many retrofit projects.

I am a qualified Passivhaus Designer and an AECB Approved CarbonLite Certifier and Modeller. This means I can model your home in PHPP, guide the design and works, and certify the finished project to the AECB CarbonLite Standard. I can provide clear, independent advice and support to help you plan, procure and deliver your retrofit project to a high standard.

What is involved:

• An initial discussion by phone or email.
• A visit to your home to discuss what may be needed, followed by a brief email report.
• If you wish to go ahead, a detailed survey of your property, so I can prepare a 3D model, floor plans and elevations.
• A review of the condition of the building and the risks of retrofit, including damp and moisture.
• PHPP modelling of the energy demand of your existing home and an improved scenario.
• To make sure the PHPP model is accurate, I can arrange an airtightness test of your home. I can also carry out thermal bridge calculations using THERM to reduce heat loss and low surface temperatures at problem junctions. Ventilation and heating design can also be undertaken, and all of this information is fed back into the model.
• From this, a whole house plan can be prepared, setting out an energy improvement strategy for the entire home. If budgets are tight, there are usually smaller, easier stages that can be done first. Keeping the whole house plan in mind means each stage builds towards the final result.
• Depending on your needs, I can prepare a specification for the agreed works and obtain quotations from selected contractors. The works can also be managed on site if required.
• Improvements can be carried out in phases over several years if needed, although this can make some tasks harder, especially airtightness.
• If you would like your retrofit certified, I can collect the evidence needed during the works and certify the completed project to the AECB CarbonLite Retrofit Standard, either in one go or step by step. Certified projects are listed on the AECB Low Energy Buildings Database.