SuperHome Database

Birmingham, Bournville, Kings Norton, Hawthorne Rd

House Summary

Harriet and Chris Martin

House Type:
1932 semi detached built in Bourneville Village Trust area

Carbon saving:
85% - SuperHomes Assessed  

Reported saving on bills:

Total invested:
£46,616 before conservatory

  • Hawthorne Rd Bourneville
  • harriet-and-chris-martin-bournville-945×646
  • 03 garden
  • Front Facade_Kings Norton
  • pergola and pv_Bournville_Martin
  • WoodStove_KingsNorton

Measures installed:

  • Cavity Wall Insulation
  • Condensing boiler
  • Double Glazing
  • Floor Insulation
  • Loft Insulation
  • Low Energy Appliances
  • Low Energy Lighting
  • Solar PV Panels
  • Solar Water Heating
  • Water Saving Devices
  • Wood Stove

Upcoming events

Early interest in Open Days encourages SuperHome owners to host more events. If you'd like to visit this property please contact the owner and let them know. SuperHomers are often happy to respond to questions about their refurbishment project by email between times. Please read ‘more on contacting this SuperHomer’ before you make contact.

What visitors are saying

“Gave a great insight into how energy consumption can be substantially reduced. The solar pv on a free standing frame was creative.”

"Very informative and helpful. Answered all questions with great clarity. Thank you once again for welcoming us into your home."

"I found the visit extremely interesting and have thought of various small things I might do."

"Hospitable welcome and no hurry on the tour. Kind of the hosts to open his and her home."

"The home was a great success and the effort made to keep the changes 'invisible' so as to fit in to the local ambience was particularly impressive. The owners had worked very hard indeed to achieve the end result."

"Inspiring example of what can be done with an existing 1930s house."

"The attention to detail is impressive and important in energy saving."

"Inspiring demonstration of home efficiency. We will be encouraged to do more to improve our house of similar design to 329 Hawthorn. We are always looking for new ideas."

"A wealth of useful information, practical suggestions and inspiration to continue to make our home and lifestyle greener. Many thanks to Chris and Harriet."

"Most informative and welcoming. Many strategies I can put into action immediately."

"This is a great example of retrofitting an existing conventional house."

"Fascinating to see the practical application of so many technologies."

"We have wanted to visit for several years... Fabulous tour! Very informative and inspirational. Thank you!"

"This has been very useful for the eco-design course I am studying for!"

Personal story:

One of us grew up in Cornwall (solid granite walls and open fires) and one in western New York State (timber frame houses with huge boilers and hot air heating). We met in 1964 on a Roman dig, married seven years later and have lived in Birmingham for almost 34 years. We spent much of our lives in education (between us teaching primary school (15 years), archaeology in adult education and as a visiting lecturer in assorted universities (20 years) and lecturing in the business school the University of Central England (20 years)).
Most of the time we were bringing up our two sons we lived in a 4 bedroom detached house in Birmingham. In 1979 we used almost 42,000kWh of gas; our electricity use peaked at 6,500kWh in 1998. By 2009 we had reduced our gas usage 65% to about 15,000kWh and our electricity usage 70% to 2,000kWh electricity. Following renovation of our “superhome” semi our gas usage is 4,000kWh and our electricity 1,400kWh per annum.
After retiring we acquired an allotment. Chris spotted the for sale sign on our current house when cycling back from the allotment. We had been considering how best to “downsize” from our by now well insulated old home (HIP rating C) and wanted to experiment super insulating a semi-detached home for our retirement.


We first became aware of the warming effect of CO2 on our atmosphere when we saw the “Keeling Curve” in 1980 and waited to see how world governments would rise to this challenge. And waited and waited.
In 2005 we joined the Living Witness Project, a Quaker initiative encouraging personal responses to climate change. Joining with others we worked to reduce the energy usage of our Quaker meeting house 91% between 2005 and 2011 doing much of the work ourselves (
We learned from this project what can be achieved and wanted to demonstrate it in a relatively “average” three bedroom semi while customizing our home to suit our retirement within the constraints of the Bournville Village Trust design guide.

Also see:
Property background:

Our house was built in 1932 by the Bournville Village Trust. In the 1960’s the owners added central heating and extended the living room by about two meters. The extension had single glazed windows on all sides and little insulation in its flat roof.
There was about 6 cm of insulation between the rafters when we bought the house but no further insulation.

Key changes made:

Replaced the very inefficient boiler and re-plumbed the central heating–pipes below the floors are now positioned above insulation. Estimate new boiler 30% more efficient.
Insulated the walls both with cavity wall insulation and with interior cladding, achieving a U value of 0.2.
Upgraded the loft insulation to achieve U value of 0.1 on edges and 0.2 in central storage area.
Replaced the old single glazed windows with argon filled, soft coated double glazing; one window now triple glazed. Estimate U values went from 5 to 1.2 and 0.8.
Replaced an open fire with a smokeless wood burner. When the central heating is on we have a fire burning. We estimate the fire provides at least 30% of our heat in winter.
Installed 2.4 kWp solar PV on a garden pergola. This provides c. 1,800kWh over the year, equivalent to our annual usage.
Installed solar thermal panels on roof. These enable us to turn off our gas hot water for about 6 months saving about 900kWh.
Insulated under the floors.

Measures installed in detail:

  • Cavity wall insulation (reduced U value from 1.42 to 0.56) (£129)
  • New central heating system includes A rated condensing boiler (£7,148)
  • Double Glazing includes patio doors (PVC, argon filled with soft low E coating; reduced U-value from 5 to 1.2) (£11,346)
  • DIY floor insulation (reduced U value from 0.6 to 0.2 & eliminated draughts) (£1,000)
  • DIY loft insulation (reduced U value from 0.7 to 0.2) (£50)
  • Loft Storage room with insulated floor & insulated hatch cover (£3,464 inc. labour)
  • DIY dry lining insulation of walls (reduced U value from 0.56 to 0.2) (£2,000)
  • Low energy A or A+ appliances
  • Low energy lighting (£100)
  • Solar PV panels (2.4kWp) mounted on garden pergola (£13,350, but prices have dropped since)
  • Solar Thermal panels (£3,350)
  • Water saving dual flush toilets (2.5/4L), eco shower heads, shaped bath (£500), 800L water butt (£300)
  • Smokeless wood burning stove (£2,959)
  • Unheated conservatory for passive solar heating (£18,244)
  • New, insulated front door (£970)
Benefits of work carried out:

We believe the home is now consuming about 85% less energy than it would have had we moved in without spending six months improving and insulating it. It is warm and snug in winter and cool and well ventilated in summer. Our bicycles take pride of place in the cycle shed carved out of the old garage. We take great pleasure in reading our gas and electric meters weekly, graphing our modest usage and trying to think of new ways to reduce it.
We are rather embarrassed to receive £200 heating allowance for a full year of gas which cost a total of £211. The main benefit or our PV electricity generation is our feeling of comfort knowing we generate just about what we use over a year. The feed-in tariff received will pay for the PV installation (including the pergola and armored cable) in a little over 15 years.

Favourite feature:

Our favourite improvement is probably the cavity wall insulation–a huge improvement in warmth for a very low expenditure! That, however, is not a particularly visible improvement. On a chilly day it is a great pleasure to watch the flames from a wood fire in our smokeless wood burner while basking in its warmth. Our incessant search for unwanted local trees also has helped us integrate into our new community.

Project update:

As well as cavity wall insulation we lined the insides of all exterior walls with about 3″ of Thermoline insulation.
We improved the high quality double glazing in our dining area with triple glazing. It’s made a big difference: when it’s 20C colder outside than in the window is now the same temperature as the wall. Previously it was 2C colder.
We have added some tertiary perspex glazing on two windows, but that seems to make very little difference.
Our next major step will be to build a front porch!

Updated on 28/08/2018

Contact this homeowner

Assessment types

SuperHomes Assessed

A home that has been visited and assessed by us and confirmed as reaching the SuperHome standard, which demonstrates a 60% carbon saving.

Homeowner Reported

Information has been provided by the homeowner about their home and energy use prior to the installation of measures and following their installation which demonstrates a carbon saving. This information has not been verified.

Remote Assessed

The homeowner has provided information on their home including what measures have been installed which has enables an assessor working on our behalf to assess their carbon savings. This home has not been visited to verify the measures installed.


This home has not been assessed, but the homeowner has reported what measures have been installed. It may be that this home is awaiting assessment.