Note: that is a pair that is best used together. The top item is an inverter that converts AC to DC and DC to AC. It does not have any storage itself. The bottom item is a 3072 Whr battery. While the battery could be used by itself, it would only be for DC powered items so it's functionality is minimal.
You are using roughly 2083 W of power on average (1500 * 1000 / 30 / 24 = 2083). Usually it is best to not use more than 80% of the power of a battery (LiFePO4 batteries like this one can go up to 100% and down to 0% but it isn't recommended to do that long-term). So, that battery has a more realistic 80% * 3072 Whr = 2458 Whr usable capacity. At an average use of 2083 W, you would consume that in 2458 Whr / 2083 W = 1.18 hours.
This particular battery isn't really useful for a whole house battery. Whole home batteries start at ~$10k and quickly go up in price from there. Check out Bluetti EP800 / EP900, Zendure SuperBase, LG Energy RESU16H, Generac PWRcell, SunPower SunVault, Blue Planet Energy Blue Ion HI, BYD HVL 12, HomeGrid Stack'd, Qcells, Sonnen SonnenCore, Lion Sanctuary, or the Tesla Powerwall. Honestly, a good gas powered generator is the better route at those prices.
The "portable" battery that I linked is really mostly good for just a few circuits in your house. I hooked it up to a 6-circuit transfer switch (although I only am using 4 of the circuits). For that I get 3 days without the furnace and 1 day with the furnace running on a significantly cold day (I also added a second battery but not a second inverter).
https://www.amazon.com//dp/B07BK63MQN
I also have solar panels that can extend that range, but you can never fully count on them. For example, the winter storm that covered much of the US in mid January dumped snow blocking most of the solar energy. And it froze solid such that I didn't want to hammer at the ice and risk damaging the panels.