I can only think the previous reviewer didn't zip up the bags properly or fully turn the valve to close. I originally bought one pack, sceptical of their claims. I have now bought several. Living in the Scottish Highlands, and having emigrated from the home counties, get lots of vistors so have lots of spare bedding. The spare bed can be two singles, or one King size, plus we have a blow up double. Because of the quick change over I need 2 sets for each combination. So the 2 single quilts, 2 double and 1 king size quilt plus a associated pillows and linen are all now packedin these. And it all fits onto the one shelf in the airing cupboard.