Been struggling with a serious cockroach problem in my home and really researched heat treatment vs chemical treatment which works best - from what I found, heat treatment works incredibly well because it maintains that critical heat level for an extended period and destroys all life stages while reaching deep harborage areas where they hide, plus a single thermal treatment usually does the job versus several chemical applications with crack and crevice spray cockroaches, though layered chemical approach cockroaches might cost less initially since heat treatment home cost 2000 to 6000 is more expensive but you won't need multiple sessions while chemical programs need ongoing visits builds up, and personally for severe German cockroach issues I'd choose professional heat treatment equipment