What is needed for new water heater in new location?

[alwaysfine]

I will be doing some repiping in the basement sometime in the future. I would like to relocate the HW heater to the other end of the house. In reality this proposed location would be the shortest distance to all hot water sources and was probably only located at the other end of house due to a chimney for upstairs fireplace. I would like to install a 40 gal gas heater next to an outside block wall. The top 2' of wall is above ground level outside. I have no problem moving gas and water connections but am not sure of what is needed for venting the heater. Do I use some kind of lined pipe through the wall and up the side of the house? Does this have to go above the roof-line? Is there a way of venting without going all the way to the roof? I did not buy my new heater yet since I wanted to investigate all options first. Any thoughts would be appreciated. Thanks

[jadnashua]

You have several choices: power vent, and closed combustion. Either of those could be vented out the side wall without having to go up. The location of the exhaust has some restrictions as does the length of the piping and how many turns it has. The power vent usually uses metal duct, the closed combustion often uses pvc (if it also is a condensing unit). Any combustion device needs combustion air, so a closed combustion (where it draws air directly from outside for combustion) ends up being more efficient. A traditional gas appliance uses interior air, which creates a pressure difference, which draws outside air in through cracks and openings all over the house. This also means you are losing your conditioned air. When you close the combustion loop with outside air, you have less air being drawn into the house that you then have to heat or cool. these types of WH are more expensive than a traditional one, but you may save some on flue costs. The power vent version is noisier, since it tends to have a bigger fan to blow the exhaust gasses out a 'non-traditional' flue (i.e. one that can rise naturally by convection).

[Dana]

What janashua said, and more:

With side-venting you also have restrictions related to proximity to operable windows & doors, ventilation air intakes, combustion air intakes to other gas burners, etc. as well as proximity to walkways in some instances. In snow-zones you may be required to keep the vent above grade by a prescribed minimum distance to limit the possibility of snow drifts blocking the vent.

There's usually a reasonable spot to side vent in most houses, but it might differ slightly from your original concept. Power vented tank HW heaters can often use relatively long runs of PVC for side venting remote from the tank location. Big-burner tankless units tend to be a bit more restricted.

Also, while re-plumbing the HW distribution it's a perfect opportunity to insulate all of the plumbing with 3/4" closed cell foam pipe insulation (available online or from some plumbing supply houses, but I've never seen it in big blue or orang box stores, which tend to only carry 3/8" walled stuff.) The keeps the water in the plumbing warm long enough between draws that you end up using less hot water, wasting less, and insulating all of the near-tank plumbing (including the T & P valve downspout & cold feed within 5-6' of the tank) reduces the standby loss. The payback on the $50 worth of insulation is typically less than 1 year even in low energy-cost areas.

[alwaysfine]

Thanks for the information. I have been looking at direct vent models of Bradford heaters so that I will not be sucking internal air from the house. I have the opportunity to do it now so I may as well. I will also make sure that I insulate the pipes. I know all these changes will improve the overall efficiency of my hot water heating. Now all I have to do is get started and check out the restrictions for placement of the intake/exhaust pipe. Thanks again.

[DL]

oops sorry