u/TrailerParkKen

I've used only water on this stuff before and it was fine for getting rid of all the debris/cobwebs/etc (houses in this neighborhood are all surrounded by mulch and wooden basement window wells, so SH would cause a lot of discoloration), however this time there seems to be some sort of staining in this section (maybe from a grill or fire pit, not sure). Does anybody have any experience cleaning this stuff with chemicals that can offer some advice?

This section has a concrete patio under it, so no worries about discoloration on any wood/mulch

Had a new furnace installed last winter and have had issues with constant heat pouring in from the exhaust pipe leading to the roof during the warm months. To the point where it feels as if the furnace is actually running in the hot months. Is this normal? Can it be fixed? Spending way more on cooling costs than before this thing was installed. Thanks in advance!