Sheela, do you have a source of bottom heat? What seeds are you trying to germinate? Bottom heat definitely helps germination of peppers and basil. Tomatoes will germinate just fine without it, but will germinate in half the time with heat.
I once found that my oven's light (oven off, only the light bulb on), with the door open 2", kept the interior at an even 86-87 degrees for germinating a tropical vine. So you don't need a "seedling heat mat" (although I love mine), just get creative.
