Just a couple of ideas on this for consideration:
In the days of old when movie posters were a thing, they found out movie tag lines did best with a six word maximum tagline. This really forces the tagline (or slogan) to be concise and witty. As a writer I do this for all the covers of my novels, and it is a self-imposed trick that really works.
Here is an example:
More Than Ice Can be Broken
Since my latest novel is about a brother and sister on an icebreaker fleeing an abusive father, the tagline causes a reader to pause in reflection. An abusive parent can beak a child's heart. A similar six-word tagline could do the same for Rocket Mass Heaters if done well
enough.
To that end, I would be wary of taglines with negative connotations. "Feel the heat" is probably not a great tagline because it is not something many people want to
experience. I have certainly felt the heat, and shortly afterwards, smelled the antiseptic smell of the local burn center.
I am not saying this is the best choice but combining Title with Tagline you could get something like this:
Rocket Mass Heaters
Where Warmth and Frugality Unite