Hydroxypropylmethyl cellulose(HPMC), Sodium Chloride and pure water were adopted to develop green cellulose ethers thermotropic materials. And thermally induced switching temperature, visible and solar direct transmittance were measured under different mixing proportion. For energy consumption, DeSTh was used to study the energy efficient effect of thermotropic doubleglazing windows with different mixing proportion. It was shown that the optimum mixing proportion of hydroxypropylmethyl cellulose(HPMC), Sodium Chloride and pure water was 2:15:100 by mass. And thermotropic doubleglazing window can reduce energy consumption by 3% and 8%, respectively, when compared with LowE doubleglazed window and common doubleglazed window in hot summer and cold winter zone.