The typical building constructions absorb the temperature wave caused temperature fluctuations of external air. It means this building construction has a thermal stability. Therefore, there is a reserve for warmth accumulation which can be used for decreasing of thermal losses. The developed mathematical model of temperature distribution in an enclosure structure allows estimating the cooling velocity of assorted designs of enclosure structures. And it shows the time which it is possible to turn off heating during the non-working period with maintenance required temperature condition in working period. This method allows reducing losses of heat energy considerably. It gives the chance to perform the optimum choice of periodic schedules of heating. Cost efficiency of implementation of the periodic mode of heating of the building is proved.