By introduction of intermittent heating of building we can reduce the thermal energy consumption for heating. But it requires the additional power of heating system. It is determined that the most effective solution for energy savings is to enlarge the heating power approximately by 50% for most of buildings. The simulation has showed that for buildings with a medium thermal inertia (time constant τ = 144 h) the expenses by employing the intermittent heating (reduced temperature period: 12 h on working days and 48 h at weekends), pays back after one year. By designing the heating system we must pay attention to thermal inertia of building. Our research showed that for various thermal inertias of building, the adequate modes of intermittent heating must be chosen. Santrauka Šildant pastata, esant papildomai šiluminei galiai, galima sumažinti sunaudojamos šilumines energijos. Nustatyta, kad papildomos šilumines galios (+50 %) sanaudos, siekiant pagreitinti temperatūros padidinima vidutinio masyvumo (τ = 144 h) pastatu patalpose ir taikant protarpini šildyma (12 h darbo dienomis ir 48 h savaitgaliais), atsiperka po vieneriu metu. Projektuojant reikia atsižvelgti i pastato paskirti, masyvuma ir šildymo sistemos galia, siekiant sutaupyti šilumines energijos bei gauti ekonomine nauda, taikant protarpini šildyma. Tyrimai parode, kad ivairaus masyvumo pastatams turi būti taikomi atitinkami protarpinio šildymo periodai.