Barbican Association Sustainability Working Group

Our remit and some ideas for reducing our personal electricity consumption

Investigating the estate's energy efficiency - a recent project

Environmental sustainability

The BA has set up an environmental sustainability group, which is busy talking to the estate office about ways of improving the Barbican's energy profile. It has also produced a set of top tips for saving energy that Barbican residents can do themselves.  The terms of reference of the Sustainability Working Group are to:

· investigate and to make recommendations on improving the environmental sustainability of the estate

· provide ideas, encouragement and responses to the Barbican Estate Office, which is working on some interesting aspects of sustainability, as well as undertaking independent research

· take account, in doing this, of the Grade II listing of the Estate.

Any recommendations are to be submitted to the BA General Council for approval.

We have started looking at the Estate's energy consumption for underfloor heating and electricity consumption for common parts. This work is on going.

Below are just 5 cost effective ideas for how we can reduce our own personal energy consumption - some or all of which you may have already carried out in your own flat. All these ideas have been tried and tested in the Barbican - and where possible we have attempted to quantify the energy savings.

We have started looking at the Estate's energy consumption for underfloor heating and electricity consumption for common parts. This work is on going.

Below are just 5 cost effective ideas for how we can reduce our own personal energy consumption - some or all of which you may have already carried out in your own flat. All these ideas have been tried and tested in the Barbican - and where possible we have attempted to quantify the energy savings.

1. Fit a smart energy monitor so you can see how much energy you are using. For example an OWL monitor clips neatly around the incoming electricity cable and should fit in most fuse cupboards. Power consumption is displayed on a wireless screen. OWLs cost about £40 and help you to identify power guzzling appliances.   2. Fix a timer to your water heater. These cost about £25 - 40 and are easy to fit. Programme it to come on for 2 hours just before you have your bath or shower - so you are not using energy heating water up and leaving it to cool down before it's used. Leaving water heaters on 24/7 is very expensive and also reduces the life of the heating element.

3. Turn down your water thermostat until you don't need to add cold water to your shower - there's no point in heating water and then diluting it! The thermostat control is at the bottom of your hot water tank. Getting the right temperature is trial and error.  Make sure you switch off the heater before you remove the protective cover.

It is possible to cut your energy consumption by up to 20% by using a timer and reducing your thermostat. In the case of one tower block flat this amounted to the equivalent of saving about half a tonne of CO² emissions a year - approximately the equivalent of driving 1,400 miles in a petrol engined car.

Cost saving p.a. £125 (based on 2 persons showering once a day).

4. Fit energy saving light bulbs - not everyone's cup of tea - but modern compact florescent bulbs are 60-80% more efficient that incandescent bulbs. LEDs are likely to be even more efficient and can give a range of light qualities.

5. Set an eco power management regime on your computer. We may hate turning off our PC, but running a computer and ancillaries 24/7 can use up to 4 kilowatts a day. Setting the power regime to an energy saving setting can make big savings over a year. For example, you can set your monitor and hard disks to turn off after a certain period of inactivity and for the system to go into standby or system hibernation if there is no further activity. To set power options on your PC:

• Open Power Options, click Start, click Control Panel, and then double-click Power Options.
• Preset time settings appear in the Turn off monitor and Turn off hard disks lists on the Power Schemes tab. You can change these settings by clicking the arrow and then clicking the time you want.

Potential cost savings assuming an 8-hour day of activity £70 p.a.

Investigating the Estate's energy efficiency

Over the summer, students and staff from the Bartlett School of Graduate Studies at University College London have been working with the BA Sustainability group to collect data and model the current energy performance of some Barbican flats. With the goal to reduce global warming and maintain security of energy supply, the Climate Change Act (2008) requires the UK to reduce CO₂ emissions by 80% by 2050, compared to 1990 levels. As the domestic sector is responsible for over a quarter of the UK’s CO₂ emissions, energy efficiency must be improved for both new and old dwellings in order to achieve this target. This summer's study is the start of a programme of work by MSc and PhD students that should help residents understand how the Estate's energy efficiency might be improved and help us to evaluate the cost effectiveness of different technologies.

UCL and the Sustainability group are very grateful to all those residents who have participated in this summer's study.

Temperature and humidity data

Temperature and humidity was measured every 15 minutes for 6 weeks from 29 May until 10 July by data loggers placed in 10 different flats. Flats were selected with different aspects and in different blocks, including Shakespeare, Speed, Ben Jonson, Bryer, Thomas More and Gilbert. Loggers collected data from bedrooms and living rooms and in 2 cases from the balcony and the central corridor.

The measurement period included some of the coldest summer days - on 19 June the temperature dropped to just over 11°C for much of the day and then just a week later there was an extremely hot spell  - on 28 June outside temperatures topped 26°C.

The UCL students are using the data collected to model the thermal efficiency of some blocks. The results should be available later in the year. Using the raw data the BA Sustainability group has also made some preliminary analyses, which are outlined below.

How the buildings respond to changes in temperature

The first graph shows the daily variation in temperature for one flat over the entire period. It is interesting that the temperature inside the flat is higher than the external temperature (balcony) for the first three and a half weeks of the study. The thick concrete walls cause internal temperatures to lag changes in external temperatures. Internal temperature variations are also smoothed - this can be seen particularly in the red line, which is the temperature of the internal lift lobby, compared with the green line, which is the outside temperature on the balcony.

The thermal inertia of the building is of course something we are all aware of - particularly in winter when it can take some days for the internal temperatures to rise in a cold snap. Conversely we are all opening windows to reduce the heat when the weather turns milder.

Blower door test

The permeability or ‘leakiness’ of the fabric was tested in the Shakespeare Tower flats. After blocking off all the known vents (windows, bathrooms, kitchens) the internal pressure of the flat was raised and then reduced by a suction pump placed in an airtight 'front' door that replaced the flat's own front door.

The study found that the flats were relatively draft proof - external windows and doors generally fitted well.

However, when the vents are open, the turnover of air inward through the window vents and under the front door and out through the bathroom and kitchen vents can be substantial and is likely to cause a significant loss of energy. Later studies will look at whether air handling in our flats could be made more efficient.

Thermal imaging

Further thermal imaging during the winter may reveal areas that may benefit from insulation. One example may be the internal walls of tower block flats that back on to the stairwell. Tower stairwells are open at the bottom and draw air up through the building. In winter they are unheated and substantial heat loss takes place through uninsulated bathroom walls - as can be seen in the next pair of photographs.

Behavioural questionnaire

Residents participating in the study completed detailed questionnaires on how they managed the temperature in their flats. For example, how often and for how long were windows open; when were blinds or curtains drawn; how comfortable did we find the temperature; did we use any form of air conditioning or heating etc.?

How we manage our flats can have a substantial influence on temperatures and comfort levels. The graph shows the temperatures experienced over a hot day - 28 June - in the living rooms of 4 flats in Shakespeare Tower.

Obviously aspect has an important effect on the timing of maximum temperatures. But you can also see that flat 1 with N to S orientation has more effective temperature management than flat 2 which also faces N to S. We can affect temperature by managing ventilation and the use of blackout or insulated curtains to block insolation.

Opening windows during the cooler night time hours and then closing the windows and drawing curtains keeps flat 1 up to two degrees cooler than flat 2 for most of the day. The 2 flats with southerly or westerly aspects experience higher temperatures but might benefit from more active temperature management.

Managing temperature on a hot day

This graph shows the temperature in one Shakespeare Tower flat during 28 June compared to the outside temperature and that in the lift lobby. The flat gets early morning sun. Temperatures in the flat were managed by leaving 5 square metres of window open from 23:00 to 06:00. The windows were then closed and blinds or curtains drawn.

Future studies

UCL hope to undertake more studies next year. Of particular interest will be data collected during the winter heating period. We will also have access to the full results of the present study when the student completes modelling the thermal efficiency of the participating flats.

We hope that the studies will provide ideas and information to help residents and the Barbican Estate office make more informed decisions about the options available to help us reduce our energy consumption and to evaluate their cost effectiveness.

Updated 26 August 2010