A while back I blogged about fridge efficiency and my idea for improving it by creating airflow over the condensors. Lance at the ATA didn't seem to think it would be effective without forced air, though since publication I've received some emails saying it will improve efficiency up to 30%, without complicated active ventilation.
As part of the Food for the Future Fair last Saturday, we took the tour of Michael Mobbs' Sustainable House. We've been there before. The biggest mistake he mentions is his fridge selection and lack of passive ventilation incorporated into the design. With a fairly small gap under the flooring, the layout of the joists meant that when he retrofitted a grill in, there wasn't much airflow.
We don't have the low floor problem, so I think I'll ensure this is in our design. We'll probably also chuck our massively-inefficient fridge and buy a better one, though I'm kinda hooked on the ice maker now.
Mobbs suggested the best approach was to have a cupboard with the fridge door attached to the door, with a grill 25% larger than the fridge on the floor and some way of venting at the top of the cupboard. That way you'll get year-round ventilation without losing room heat in Winter. I like that idea a lot!