Most portable heaters or air conditioners draw a lot of electrical power—typically around 1,500 watts. This is nearly enough to load up an entire circuit, as an average wire and circuit in a home is 15A (1,800 watts).
There’s few wired spots in a home that allow these appliances to be run without tripping a breaker, but code doesn’t require this much power, nor considers it for portable heating and cooling. A new dedicated circuit is likely needed to power this equipment properly.