All depends on your setup, I have 120 feet or so of sidewalk thats heated too, between the DHW, a 110,000BTU HX in the furnace and the sidewalk, with only 5gpm my delta T would be horrendous if everything was running at once, if its cold enough out the sidewalk can pull harder than the DHW and the HX in the furnace.
I’m running roughly 117’ of Logstor, then it’s all 1” copper in the basement with primary/secondary loops to everything, running a Taco Delta T pump that keeps up very well if you ignore the lag. Will most likely be adding a whirlpool tub in the future along with some radiant or something upstairs.
The wife has mentioned a time or two about doing a heated driveway for where she parks, only 75’ of that then….
Told her once I figure it out she can cut the extra wood.
I know how hard the sidewalk pulls, my system would fall flat on its face if I was only heating the wheel tracks for that drive.