It doesn't work that way. A 110/220 transformer generating 5A/220V on the secondary would need to draw 10A/110V +losses on the primary. Same amount of amps from your meter. No reduced risk of problems with authorities and no less load on your main fuses. What it would help with is getting the needed amount of power to your basement if installed between your main and group fuses/breakers. Line voltage where I live is 230V (400V between phases) so no experience of these transformer setups but basic laws of electricity apply.
As for your basement's breaker capacity, check your fuse/breaker box. Not very likely your basement can handle 7kW as it is.
Hope that makes sense. I'm not a native speaker so my elec-english is not perfect.
Anyway, if you're interested, maybe you should consult a real electrician right here on this board:
https://www.rollitup.org/grow-room-design-setup/181708-experienced-electrician-here-answer-any.html
As for your basement's breaker capacity, check your fuse/breaker box. Not very likely your basement can handle 7kW as it is.
Hope that makes sense. I'm not a native speaker so my elec-english is not perfect.
Anyway, if you're interested, maybe you should consult a real electrician right here on this board:
https://www.rollitup.org/grow-room-design-setup/181708-experienced-electrician-here-answer-any.html