Why is there no insulation for saucepans? Or around kitchen sinks or bathtubs? Is it difficult and expensive, or just a lazy tradition inherited from wasteful innocent times?
鈥� There is no insulation on saucepans because it would hamper the heating of the pan鈥檚 contents. Pots and pans use heat-conducting materials to make heat transfer more efficient.
Plastic baths keep bathwater hot much better than old-fashioned metal ones. However, if a long, lingering bath is your desire, you could remove the bath panel and fill the air space around the bath with mineral wool 鈥� the kind used for loft insulation. You may also wish to consider using bubble-bath because this diminishes evaporation from the water surface, the main source of heat loss from plastic baths.
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As for sinks, how long does it take to wash some dishes? If you have lots of dishes, the water will probably get dirty and should be replaced for hygiene reasons before it has cooled.
One lazy tradition inherited from wasteful innocent times is lying soaking in a bath for ages, like the Romans.
David Muir, Edinburgh, UK
鈥� Using gas, and to a lesser extent electric radiant cooking, a pot is heated from the sides as well as the bottom. Insulating it would be a little self-defeating.
Energy and water efficiency were two of the driving forces behind the design decisions I made for my self-contained, all-solar-powered motorhome.
Using my induction cooker, I tested a collapsible silicone kettle against a conventional metal one. There was no significant difference in time or energy taken to boil the same volume of water. An immersion kettle took less time but the same energy. I concluded that the heat loss through vessel sides and top was small relative to the heat input. The bigger waste is likely to be boiling more water than required. I haven鈥檛 pursued side or lid insulation for pots, but I use a slow cooker, which puts the heated pot in a vacuum-insulated container.
鈥淎 cooking pot is heated from the sides and the bottom. Insulating it would be a little self-defeating鈥�
I did consider whether large-diameter pots were more water and energy efficient than small-diameter ones, but the differences were minimal.
I based my selection of a motorhome sink on minimising thermal mass, maximising depth of water for minimum volume, and being able to fit our largest dish or pot into the sink to wash it. Insulation was a given, but I had to add it myself.
Julian Lawrence, Karana Downs, Queensland, Australia
鈥� Tradition certainly plays a role; our ancestors of centuries ago had little understanding of energy conservation, and few effective options for insulating material. Even so, shortages of fuel led people to use techniques such as haybox cooking, in which food is first heated to boiling then kept in a box insulated with straw until cooked. It was slow, but it worked.
Nowadays a wide variety of insulated cookware is available and generally works well, especially for people who work all day and like to come back to ready-cooked meals.
As for sinks and pipes, modern materials have led to all sorts of insulated plumbing, whereas insulation in the past tended to be expensive and fragile. Newer baths and hot water pipes are made of plastic, which is reasonably insulating, so they retain heat fairly well. In flats where I lived as a child, the hot water supply was heated centrally and distributed through metal pipes. These conducted heat away from the water, until my father showed the owner how to make insulating cement jackets for the pipes.
Jon Richfield, Somerset West, South Africa
鈥� A range in stainless steel pots, with evacuated double walls and lids, was popular in Switzerland some 20 years ago. It was marketed abroad at least as far as Austria and I secured a set for my godchildren who lived there.
Since then, they have faded from the hardware departments of Geneva and appeared absent in the rest of Switzerland these past four years. This cannot be due to poor durability because the pots I took to Austria were still in regular use, and good condition, when I cooked New Year鈥檚 lunch earlier this year.
Peter Urben, Kenilworth, Warwickshire, UK
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