Wilfy,point taken about the expense. Afriend of mine insulated his workshop (small factory) by visiting all the local electrical stores and collecting (did them a favour) all the unwanted polystyrne packaging (washing machines, etc.).He then broke it up into small pieces and sealed it into black (non biodegradable) bin bags making like pillows. This worked for him, but was a lot of work, but more importantly virtually no cost.Reards,G