I went through our gas bills for a year:
Jan 182 CCF
Feb 153 CCF
Mar 109 CCF
Apr 68 CCF
May 18 CCF
Jun 15 CCF
Jul 21 CCF
Aug 91 CCF *
Sep 23 CCF
Oct 46 CCF
Nov 117 CCF
Dec 140 CCF
* Extended power outage; running on generator
During the summer, our gas usage is primarily the water heater which averages out to around 19 CCF/mo
Total heating season (Oct through April) less 19 CCF/mo for water heater = 682 CCF which I believe is equivalent to 20 MW-hr
The sand battery as presented could store 8 MW-hr with the sand at 600 deg C
Just looking at the worst three months (Dec, Jan, Feb) -> 12 MW-hr
So for seasonal heating, we'd need about 1.5 sand batteries as presented (150 tons of sand). It would take a resistance heater to get temperatures needed to store that amount of heat, so I suppose it would have to come from solar panels. A 10 kW array operating 6 hours per day during half the year = 11 MW-hr.