Venting boiler out the side of a building.

July 19, 2014 9:23 PM

I am doing a renovation and I'd prefer to move the boiler to a location where I have to vent horizontally, under a porch that is 7' wide. Do I have boiler options that allow this. I currently understand that a regular boiler must vent straight up. A high efficiency boiler can vent out the side wall. However, I don't know if you can vent a high efficiency boiler out 8' horizontally.
posted by alcahofa to Home & Garden (9 answers total)

This doesn't answer your question exactly, but I had a similar problem and ended up just switching from gas to electric instead of trying to find a way to vent the darn thing.
posted by Violet Hour at 9:50 PM on July 19, 2014

I have a boiler in my basement, the vent pipe comes out of my wall horizontally to vent under a deck/porch... the vent pipe extends about two feet outside the wall under a deck that extends another 4 feet.

I have no idea if this is built to code (the house was built by the former owner who knew very little about the heating system he installed), but I've owned the house for about 4 years now and it's not been a problem (other than a bit of frost that forms on the deck if the outside temp is very, very cold).

Contact a local heating contractor.
posted by HuronBob at 3:44 AM on July 20, 2014

Can it be vent 8' horizontally? See the data sheets. It should state, explicitly, what the limits are for the chimney. If not you could get in touch with manufacturer and they'll have an answer. My gut assumption would be, 'Most likely'. As the exhaust is driven by a fan and if the chimney is sized correctly it should be pretty straightforward.
posted by From Bklyn at 3:44 AM on July 20, 2014

Talk to your contractor/plumber and your town's building inspection department.

This is not a DIY thing at all. The contractor you choose should be able to guide you to the solution that works for you.
posted by Ruthless Bunny at 5:48 AM on July 20, 2014

Yeah this is the kinda thing mechanical contractors are meant to do. Don't do it yourself.
posted by Sternmeyer at 6:28 AM on July 20, 2014

I would think that most high efficiency boilers would have no issues with 8' horizontally. Provision must be made for drainage of condensation. As above, check the data sheets.
posted by ssg at 7:50 AM on July 20, 2014

As Bklyn says, the answer will be in the spec. sheet of each specific unit.
posted by humboldt32 at 9:51 AM on July 20, 2014

Mine vents 10'. I bought it specially and had it installed professionally. It does have to slope upwards.
posted by fshgrl at 2:17 PM on July 20, 2014

There's some code issues that don't allow you to vent within {x} feet of a door or window.
posted by Ham Snadwich at 7:13 AM on July 21, 2014