Turn up the heat, push out as much air as you can and still keep the temperature up, and pay the utility company...
Greenies and your wallet will be weeping, but it’s fairly cheap prevention, all things considered, esp. if one has a high risk member of the household.
That’s sort of what we are going to do with my Mom. Put a window fan in an upstairs window, pushing air out, and run up the heat downstairs, where she stays. (Kinda wish she was upstairs and we’d exit air downstairs, but there is no shower or tub upstairs, and she is wheelchair / walker (a few steps) bound.) Plus the thermostat is downstairs in the area she usually stays in. That’s convenient! I really wish we could keep her mostly in her bedroom (fairly large, could put a TV in there, etc., but she won’t stand for it, at least just yet.)
I have 4 of those standup quartz radiant heaters, which helps, for spot / zone heating. Only problem is the safety thermal breakers in them get flaky with age & shut down way too soon. So I can only run ‘em at half power (which does greatly mitigate the risk of overloading a circuit, if used one per circuit and no other heavy power consumers on said circuit.)
Gosh, I know what you’re going through.
Hate to pay for that “outside air”. It ain’t cheap.
But it ‘s better to so in the end.
With the window fan pushing the virus out, what about anyone outside in the yard?
We have plans for an isolation room but I’ve had concerns that opening the ground floor isolation room windows will just blow it to the yard and back into the house. Pets will bring it in. Kids will bring it in. Neighbors will bring it into their houses.