A bit of information on mattresses with springs that you may find useful. I recently borrowed a gaussmeter from our local electricity company to measure EMFs at our meter box (which is situated on a bedroom wall) and decided to measure in other places while I was at it. I had read that sprung mattresses are unhealthy as the metal springs conduct electricity, so decided to test this theory for myself.
I started with ambient EMFs, just to have a reference point. The ambient reading in my home is about 0.6, and this reading was similar out in the garden. I was interested to find that the reading all over the mattresses with springs was exactly the same as the ambient reading – in other words, there is nothing to worry about if you have a sprung mattress (of course, the chemicals are another matter). – Madeleine