The blinds are very easy to operate being raised using a cordand lowered by simply pulling on them while keeping some tension in the cord.  Because of the nature of the radiant barrier material and the fact that the blinds move up and down in channels attached to the window framing, you can sit beside the windows on a cold night without feeling any draft or discomfort.   

There is, however, a disadvantage to the tight seal provided by the blind.  It prevents warm room air from washing over the window as normally happens (to various extents) with conventional blinds or when a window has no covering at all.  At outside temperatures colder than about -8 degrees Celsius, there will be significant condensation on the inside of the windows in the morning when the blinds are raised.  This is not surprising or unexpected.  When the temperature of the air in the cavity between the space blind and window decreases, the capacity of the air to hold vapor also decreases.  At some point, vapor will condense on the inside surface of the glass.           

After a few months of experimentation, it appears that a reasonable way to greatly reduce (but not eliminate) the condensation problem on nights when it is colder than -8 degrees Celsius is to use a pencil placed flat on the window sill to prop up the bottom of the blind.  The resulting gap allows a convective current to develop behind the blind with warm air being drawn in behind the blind at the top and, unfortunately, cool air being discharged through the gap at the bottom.  Of course, this makes the blind less effective and needs to be done on nights when you really want the blind to be down all the way.  However, it eliminates or reduces condensation down to temperatures of about -15 degrees Celsius.  During the 2007/08 heating season, only 5 percent of the nights were colder than that (see chart) so on those nights, either the blinds can be left partially up or the condensation/frost can be removed with a cloth in the morning.