Patrick Delgado, Gas & venting writer

I write the gas side of the site: gas versus electric, natural gas versus propane, condensing versus non-condensing, indoor versus outdoor. Those four questions decide more about your install bill than the brand on the front panel.

My habit is to read the manual backwards. The venting chapter, the gas supply table and the clearances come first, the feature list last. A big BTU number looks great on a listing, but it only helps if your gas line and meter can feed it, and the manual usually says so in a table most buyers never reach. Venting works the same way. A condensing unit can often vent through PVC, a non-condensing one needs stainless or a special vent system, and that changes the price of the job.

With propane, I check whether the model is sold as its own propane version or needs a field conversion kit, and who the manual says may fit it. With outdoor units, I look at the freeze protection and what it needs from you, which is usually power to the unit.

We haven't installed these heaters ourselves, and I won't pretend otherwise. I read, I compare, and I point out what the listing leaves out.