Temperatures can drop to -40C in Siberia, which means that broken heating systems can be deadly.
The Kremlin’s mobilisation order in September drafted 320,000 men into the Russian army, but three or four times that number fled abroad. This has left Russia with a shortage of labourers.
A survey by the Gaidar Institute in Moscow said that a third of Russia’s industries are now short of workers. Plans have been made to draft in extra workers from Central Asia to plug the shortfall, but until then many households will face freezing temperatures.
It comes as Russia has inflicted “colossal” damage to Ukraine’s power grid, said officials, causing rolling blackouts that could last until March.
An estimated 70 per cent of Ukraine’s power-generating capacity has been destroyed, the World Health Organization has said, with 10 million people in Ukraine living without power.
To conserve energy, Ukrainian authorities have asked relatively wealthy people to travel to Europe. They have also set up thousands of tents in cities with generators for people to charge their mobile phones, warm up and eat a hot meal.