http://tanklesswaterheatertoday.com/how-many-btus-can-a-34-pipe-provide/ everything you need to know about tankless water heaters Tue, 13 Dec 2011 11:13:23 +0000 hourly 1 http://wordpress.org/?v=3.2.1 http://tanklesswaterheatertoday.com/how-many-btus-can-a-34-pipe-provide/comment-page-1/#comment-986 adevilch Sun, 20 Dec 2009 00:42:49 +0000 http://tanklesswaterheatertoday.com/how-many-btus-can-a-34-pipe-provide/#comment-986 According to the quick reference guide "Code Check Plumbing", a 3/4" pipe carrries 250k Btu's at 20' and 200k Btu's at 30'. A 70k furnace, 120k water heater, and typical gas range (65k btu) adds up to 255k btu/hr. So a 3/4" pipe isn't big enough if you use your water full out. A typical shower only uses the demand heater at a lower level, so you're probably just fine if yours has multiple settings, like a Takagi. But if you ever get a clothes dryer you're in trouble. According to the quick reference guide “Code Check Plumbing”, a 3/4″ pipe carrries 250k Btu’s at 20′ and 200k Btu’s at 30′. A 70k furnace, 120k water heater, and typical gas range (65k btu) adds up to 255k btu/hr. So a 3/4″ pipe isn’t big enough if you use your water full out. A typical shower only uses the demand heater at a lower level, so you’re probably just fine if yours has multiple settings, like a Takagi. But if you ever get a clothes dryer you’re in trouble.

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