The UK government is already legally committed to an 80% reduction in CO₂ emissions by 2050, (from 1990 levels), and has accepted since the Paris climate deal that eventually there’ll have to be a 100% reduction. Architect Nigel Humphrey wanted to ensure that the refurbishment of his own home reflected a similar ecological stance especially as he and his family plan to live there for twenty years or more he needs to make the house as energy-efficient as he can. In this story of he project, Nigel explains how he went about it …

Introduction

my family moved house two years ago and hope that we’ll stay here for a long time. So, we want the house to be comfortably warm and affordable to run on a pension. To make this really obvious we rented a bungalow for a year whilst the work was carried out on our house and the £2500 that we paid for the gas and electricity was shocking. After 12 months in our house I’m very pleased that the total annual energy cost is only £500. Our last house was the subject of my MSc Thesis in which I looked at the CO₂ reductions achieved within the context of a Carbon Footprinting analysis. An 80% carbon reduction across our whole lifestyle required very good performance in all areas including our Dwelling. That house would need some expensive additions to meet the target and in truth was just too big. This house is smaller, and I wanted it to be as close to zero carbon as we could get on the budget of £50,000 for the main house, and £70,000 for the extension.

Zero-carbon, Code for sustainable Homes, BREEAM, Passive House; let’s call them Ecohouse’s as shorthand; all require the renewable energy used to be produced on site but the measures required to reduce the energy load on an existing house to a level where this can work are very expensive and present a lot of problems. At the AECB conference in Nottingham we saw two examples where the refurbishment costs for a typical 3 bedroom terrace house were about £130,000(?)

I didn’t have that kind of money to spend, how many people do? Our response has been to use a mixture of renewable electricity produced on site and renewable electricity imported through the National grid from Good Energy. We want our electricity bill to be as low as possible so we’ve tried to make the house as energy-efficient as we can.

The house structure is a two storey detached dwelling built in 1947-8 as one of a pair with tiled pyramid roofs and a central flue, a garage and workshop to the North East side and a terrace to the South West side. It is of an unusual construction with a suspended reinforced concrete first floor, 75mm cavity, larger than usual bricks and mortar joints, and minimal amounts of timber, (probably due to the materials shortages in the immediate post-war period). The original Crital single glazed windows had long since been replaced with early versions of horizontal sliding sash Aluminium windows

The existing gas boiler was very old and inefficient, as were the clock timer controls, the micro bore distribution pipes, and single panel radiators which all dating from the 1970’s. I could tell because the pipes running through the unheated Attic to the radiators on the first floor had all been lagged with newspapers from the 1974, mostly The Express I think. The old Aluminum double glazed window units had all failed and were incredibly leaky having been very poorly fitted, and there were air bricks everywhere open to the cavity, which also had no insulation. There was about 80mm of vermiculite insulation between the joists in the Attic, and no insulation to the solid ground floors.

Heating the house must have cost a fortune and produced huge clouds of CO₂.
What it did have going for it was the orientation toward the South with the Kitchen facing South East and the Sitting Room south West. It was also structurally sound and thermally massive, with pre-cast concrete slabs forming the first floor and solid floors at ground level.

Click on the page number links below to read the rest of this story