  We present a nonparametric method to determine the sign of $w+1$ in the
equation of state of dark energy. It is based on geometrical behaviour and is
more tolerant to uncertainties of other cosmological parameters than fitting
methods. It permits to distinguish between different classes of dark energy
models even with relatively low precision data. We apply this method to SNLS
supernovae and to gold sample of re-analyzed supernovae data from Riess et.al.
2004. Both data sets show strong indication of $w < -1$. If this result is
confirmed by more extended and precise data available in near future, many of
dark energy models, including simple cosmological constant, standard
quintessence models without interaction between quintessence scalar field(s)
and matter, and scaling models are ruled out.
