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.

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!”

Uni teaching block launches large Passivhaus in the UK

Case studies for Passive House Plus: new build

UK’s largest passive building opens to 2,400 students and staff

University of Leicester – the new Centre for Medicine

Completed early this year, the new Centre for Medicine at the University of Leicester is by far the largest single building in the UK to meet the passive house standard — and not surprisingly, its design and construction posed tough new challenges on how to meet the rigorous low energy standard on such a large, complicated building. December 2016

 

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Community deep retrofit

Working with design consultancy URBED, Manchester-based community energy group Carbon Co-op has pioneered a way of supporting ‘able-to-pay’ homeowners to invest in making their homes warmer and more comfortable – while reducing their energy use by around half.

By upgrading the fabric of homes and adding PV panels, cuts of 40-60% or more were made in  energy consumption and emissions and £1,000/year was knocked off bills, at a level of capital spending that homeowners were willing and able to invest. Continue reading “Community deep retrofit”

Passive school learning refines the design

Building a better passive school

Wilkinson School, Wolverhampton

The team behind a series of passive house schools in Wolverhampton have used the lessons learned from in-depth monitoring of the first two buildings to make the third even better — and cheaper to build. Oct 2015

 

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Natural materials make a warm, homely Passivhaus

Ledbury passive house embraces warmth, wood & light

The ‘modern organic’ style of the Ledbury Passive House

For the builder and his client, aiming for the passive house standard was just one part of an environmentally conscious approach that put natural, healthy materials to the fore.

The style of the house inside and out is what the owner calls ‘modern organic’ – white paint and render, and lots of natural wood. The carpentry is beautifully finished, with charming bespoke touches. Not everyone expects a passive house to be like this…Nov 2015

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Cold is not the whole story – what the health services need to know about housing

An AECB consultation response

This document was written in response to a NICE (National Institute for Health and Care Excellence) 2014 consultation on producing guidelines for health authorities on tackling excess winter deaths and illnesses. It was written (mainly) by me, on behalf of the AECB, teaming up with Severn Wye Energy Agency and the STBA (Sustainable Traditional Buildings Alliance) – who also contributed information.

While at the time of this consultation the deleterious impact of cold living conditions on health were well known – prompting the consultation – poor indoor air quality was less discussed.

Yet of course, air quality can be very poor in cold homes: people will block out any draughts they can – including the intended fresh air supply from a ventilation fan or vent – especially if they are in fuel poverty. This only increases the risk of condensation and mould – already high in a dwelling with cold, uninsulated surfaces. And more and more evidence is piling up of just how bad mould in particular is for people’s health and wellbeing. Continue reading “Cold is not the whole story – what the health services need to know about housing”

Deep retrofit – the big prize?

Simple home energy efficiency improvements (such as new boilers, cavity wall insulation etc) can bring valuable comfort and health benefits to the occupants of inefficient homes – especially those in fuel poverty – as the last article revealed (see here). However, energy, carbon and bill savings tend to be modest, rarely topping 15% or 20% – and sometimes energy use actually increases!

If housing is to contribute its share of the 80% cuts in carbon emissions this country is committed to, in order to play is part in tackling climate change, retrofits will need to go deeper – a lot deeper. But will occupants benefit from the extra work? And is it affordable? Continue reading “Deep retrofit – the big prize?”