# Difference between Direct-Vent & Power-Vent HWTanks



## Crispy (Nov 10, 2008)

Getting quotes on a new furnace and hot water heater , furnace choices are easier , but having trouble getting straight answers on hwtanks .

Im on Nat Gas and was wondering about efficency/cost/reliability-quality of the 2 differ types of water heaters ( power & direct vent models ) , is it just an exaust difference or actual piping difference .

Wanted to get rid of b-vent entirely since im going high-eff on the furnace so wondering what best choice would be .

Choices are Rheem , Bradford White and John Wood mostly

Im in Alberta , Canada if that matters 

Thanks , Chris


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## The Coastal Craftsman (Jun 29, 2009)

From what i know it depends on where your boiler is mounted. on an external wall, close to roof or in basement. Both types are designed for different installs. Im sure someone on here can tell you what one would best suit your needs. Maybe some more info like where in the building the thing is going to be mounted.


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## Crispy (Nov 10, 2008)

Well we always install our water heaters in the basement , because why flood your house if it bursts and is installed on your main floor or by roof ( cant understand why they would be installed above living spaces ) As for mounting , that would be tankless systems like Navien and Rinnai . Im finding out its more of an air movement issue . If your house is fairly airtight , like mine . I need to go with a power vent model because the direct vent might have to much blow back because not having enough movement in house already . Still trying to figure it out but thanks for the response anything to help


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## The Coastal Craftsman (Jun 29, 2009)

I have mounted on demand boilers, hot water cylinders and boilers from everywhere from basement, Garage, First floor, Second floor and even lofts quite a few times. Almost every install required a different spec of boiler venting. Some would require more intake vents into the room the boiler was in or some would require more powerful fan systems to move the air through long runs of vent. Some boiler would also have a combination air intake and exhaust. What im trying to say is theres a system to suit almost every setup and you need the system suited to where your system is situated. 

As an example a direct vent would be mounted on a external wall. 
Powered vent would be used on a long horizontal runs like when the boiler is in a middle room of house and venting has to run trough another room to exit building. 
a conventinal system(some call them direct) works just like they always have but they are limited in where they can be installed.

Hope that explains a little better.


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## Crispy (Nov 10, 2008)

Right on thanks BC , true every situation is a little different , 99% of new homes built here ( im a drywall contractor ) all have the water heaters in the basement , as well as the tankless . Unless its a rancher with no basement , fairly rare here unless in rural areas then the tank would be installed on the main floor . Or a house with a suite in it would have 2 of course so ya i see what your saying. Ill be going with power-vented i think , dont want any CO2 problems


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## The Coastal Craftsman (Jun 29, 2009)

Crispy said:


> Right on thanks BC , true every situation is a little different , 99% of new homes built here ( im a drywall contractor ) all have the water heaters in the basement , as well as the tankless . Unless its a rancher with no basement , fairly rare here unless in rural areas then the tank would be installed on the main floor . Or a house with a suite in it would have 2 of course so ya i see what your saying. Ill be going with power-vented i think , dont want any CO2 problems


 
Beware though that if you run gas and have a conventinal flu then you have no issues with power cuts and no hot water. as soon as you start adding powered fans to a heating systems then you have more to go wrong and no heat on power cuts. Most HW cylinders can keep warm for 4-5hrs so short powercuts are no issue. If you can keep it simple as possible.


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## protechplumbing (Oct 10, 2008)

power vent means a fan moves the flue gases.

direct vent mean that both the intake and exhaust are piped directly to the exterior.


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## protechplumbing (Oct 10, 2008)

Actually, depending on the tank design, they can stay hot for up to a week. The trouble is when you want to draw large volumes of water during a blackout.



BCConstruction said:


> Beware though that if you run gas and have a conventinal flu then you have no issues with power cuts and no hot water. as soon as you start adding powered fans to a heating systems then you have more to go wrong and no heat on power cuts. Most HW cylinders can keep warm for 4-5hrs so short powercuts are no issue. If you can keep it simple as possible.


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## Crispy (Nov 10, 2008)

Ya the power outage issue is why i didnt go with a tankless unit , at least the pv hotwater tank will hold enough for a while anyway


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