How much heat come off these things?
I have a covered deck the roof has vinyl on the underside and the house exterior on the deck is also vinyl. The rest is screened in floor to ceiling.
Does this thing create enough heat to be an issue?
Of course it will not be on the vinyl wall side when cooking.

My grills are certainly a no no which is why I rarely use them anymore. Lugging everything up and down and around (poorly designed stairs to get down) is a pain.

I've never noticed an abundance of residual heat off of mine so I would think you'd by ok.

If you're asking this because you're thinking of buying one, see if you know someone who has one and ask them to fire it up for you. Actually being near one would be about the only way you'd know if you'll be comfortable running one where you're wanting to.

Shouldn't be a problem. Mine doesn't throw off a large amount of heat plus if I'm only cooking for the 2 of us, I only light 2 burners.

Depending on the height of the ceiling of the deck.

I'd also be worried about grease. Whatever is above the griddle is going to get yellow from the grease.

I just got a 4 burner version, and they put off 60K BTU's. The griddle sits just off the surface of the supporting structure, which allows the heat to get around it on all 4 sides. For example, if you put a plastic cup or dish on one of the side areas beside the griddle, it can melt it in short order if you aren't careful.

I would say it can put off the same heat as a grill, if that's a help at all.

Don’t place too close to the vinyl siding on the house. It will melt it

Mine delfects a lot of heat out the sides and back. I make sure it’s clear of anything that could melt.