I found the guidelines too cool for my DD. We keep the heater on 16 degrees and have her in a singlet, long sleeve pj top and a wondersuit. She's in a 2.5 tog grobag with two blankets as well! I found she would wake up cold if I put her in anything less. We used to have the heater higher but found she would wake up more because it's quite drying (central heating) and noisy too!