Lighting based on LED has been shown to improve the quality of sleep and to improve well-being in the elderly. However, it is not known whether CALED mimicking a normal circadian rhythm has the same benefits for elderly persons with frailty or dementia. The investigators therefore want to test the effects of CALED in elderly people with frailty and mobility disabilities and/or dementia living in elderly housing. The investigators hypothesise that CALED can improve sleep and well-being in both elderly with frailty and dementia.