Insulatiion a room.

[Josh Bertolet]

In a house I just bought, 1 unit has a small 10x11 living room that currently has no insulation in the walls or ceiling. It has a drop ceilng so I have access to the top 10" or so of the walls. If I wasnt paying for heat I wouldnt worry about it but I am. What methods can anyone suggest for getting insulation in the walls without tearing them down? Its lathe and plaster so it would be very messy to pull out. I pay for gas, I thought maybe some electric baseboard heaters might heat the room up to tolerable temps. Any suggestions would help.