You could place the inverter in the same room you are heating with 220 V AC and improve the efficiency a little. Whatever "waste" heat the inverter produces because of its inefficiency will go toward heating the room.
A one meter square solar panel collects about one kilowatt with maybe 15% conversion efficiency to electricity on a cloudless summer day at noon, maybe a bit more with high-tech (expensive) wide-spectrum photo-voltaic cells... so maybe 150 to 250 watts delivered to your inverter. Less during the winter when the Sun is lower in the sky.
That same one square meter configured as a plane mirror that tracks the sun will deliver almost all of that nearly one kilowatt of power as heat. Just aim it at a window as
@BobK suggested. Hang a black cloth (or a black-painted metal sheet) inside to absorb and convert the Sun's rays into heat. You should be aiming your sunbeam through a double-insulated window so you don't lose much of the heat back to the outside.
No need to focus the Sun's rays; flat mirrors work fine for moving sunbeams around. Maybe use polished aluminum to avoid the weight and hassle of mounting a glass mirror. A skylight through the roof works well, too, if you don't mind cutting a big hole in your roof. You can line the hole with reflective surfaces to improve collection efficiency without resorting to movable mirror(s). All sorts of ways to collect solar energy for use as heat, but photo-voltaic panels aren't one of them.