Welcome to my site – a collection of some of the articles and resources that I have written or contributed to.

Generally you will find a summary on here, and then a link to the article/resource, wherever it was published.

If you want to get in touch, see the ‘about me’ page under ‘about’.

(note: posts appear in the order I add them here, not the order of original publication, but hopefully by using the categories  in the menu or the search function, you can find what you are looking for)

Can I fit a heat pump? What do I need to know?

At the start of 2022 we finally got rid of the gas supply to our home, and retrofitted an air source heat pump. With the high proportion of renewables in grid electricity now, this has led to an absolutely huge cut in our household carbon emissions, and we are delighted with how it has performed so far.

picture of a heat pump
Our Mitsubishi Ecodan

While we were planning this, I wanted to know more about what the process entailed and what we would need to think about – so I decided to write an article about it. I learned so much that I ended up writing a two-parter. Continue reading “Can I fit a heat pump? What do I need to know?”

What is thermal bypass, and why does it matter?

I am greatly indebted to the meticulous working and thinking of architect Mark Siddall (LEAP architecture) here. He’s been talking about thermal bypass for a while, so I asked him to walk me through the basics.

What the term ‘thermal bypass’ means is cold air (usually cold – though of course in summer it could be too hot instead) washing through building fabric, and undermining the thermal performance.

This means that in winter, cold air may be moving around in the walls and roof and taking heat from indoors, even if it doesn’t actually break through any air barriers. A classic example is when insulation is loosely bunged into a cavity, and warm air behind the inner leaf is drawn away and replaced with cold, when it should be held snug against the fabric.

My interview with Mark and some explanations and examples were written up for SIGA, and you can read them here.

A leaky fabric is no substitute for ventilation

In some corners of the construction community there is still a lurking belief that a leaky fabric is needed in order to ensure good indoor air quality.

But gaps and cracks are random, and the air flow through them, even more so. Believing a leaky fabric will contribute usefully to indoor air quality is an act of blind faith. Continue reading “A leaky fabric is no substitute for ventilation”

Cotswold stone warehouse becomes Enerphit hostel

The Barrel Store; once a warehouse, now a super-low-energy hostel: photo courtesy New Brewery Arts / The Barrel Store. Photography by Max McClure

This 150-odd-year old historic stone warehouse in the centre of Cirencester has been very carefully converted to create a youth hostel, providing much-needed budget accommodation in this pretty Cotswold town.

An Enerphit retrofit lifts the comfort way above the usual draughty-old-house-that-was-impossible-for-the-owners-to-heat that may be many people’s experience of UK youth hostels. Continue reading “Cotswold stone warehouse becomes Enerphit hostel”

Downsizers’ Passivhaus marries natural materials with high renewable tech


This light and airy Passivhaus was built by a retired couple who wanted to downsize from their awkward older home, to one that would be eco-friendly, comfortable, and work well whatever their future needs.

The successful result is an attractive, warm, modern-looking house. The structure is timber frame with wood-based insulation; the roof meanwhile is basically all PVs, and a heat pump and battery complete the comprehensive renewable set-up, minimising the need to import – and pay for – any grid energy.

Read the article I wrote for  Passive House Plus magazine here.

Straw-build Herefordshire Passivhaus – one of my favourite case studies!

black coloured timber clad wall with shaded window and pot plants in front
Detail of the charred cedar facade showing lowered sunshade for summer comfort. Photo: Juraj Mikurcik

Juraj Mikurcik’s beautiful little self-build Passivhaus is a house that I can totally imagine living in myself, and absolutely loving. Continue reading “Straw-build Herefordshire Passivhaus – one of my favourite case studies!”

Preston (and other) failed retrofits on Radio 4

The story of the failed retrofits in Preston, along with similar issues faced in Blackpool and – this time, with cavity insulation – in Leeds, were covered in an item by Zoe Conway on the BBC Radio 4 Today programme. I helped Zoe with some background, but she did a lot of work visiting the sites and interviewing occupants, and I think this was a pretty fair account.

The report can be heard here, until the beginning of December: https://www.bbc.co.uk/sounds/play/m0001282 -starts at approx 1hr 33m.

The Radio 4 item was also picked up by Mail Online later that day.

You can read my original post, which includes a link to my article in Passive House Plus,  here