water store used to heat house

79% of the energy consumption accounts for space heating in a single household in Alaska.
This video explores the use of thermal storage to mitigate the cost of space heating while pursuing the use of renewable resources to heat the living space.
In the fall of 2013, a 25,000-gallon tank was buried next to the Cold Climate Housing Research Center [ CCHRC ] building addition.
The CCHRC aims to heat the new building without the use of fossil fuel. Bruno Grunau, CCHRC research engineer,  explains that the thermal storage will provide
40 to 45% of heat required to heat the building. Grunau, also shows what consideration went into the use of thermal storage in his own home in Fairbanks.
Here is a range of topics they have covered.
https://www.youtube.com/user/ColdClimateHousing
And here is the storey of hot water heating

There's a house on the south end of Vancouver Island that has 3 large, insulated, water storage tanks which are heated with a water solar panel and can be circulated through in-floor heating. Coupled with the efficiently designed house, it provides all the heat they need. It's been doing so for at least 15 years.