water heater flue

[nellson]

My builder is telling me that if I opt for a high efficiencyfurnace (closed combustion) I must also install a closed combustion water heater. The reason given is that the flue is too long (high) for a regular water heater without a furnace being connected also. This doesn't seem right to me since every water heater must operate even while the furnace is not operating. What am I missing?

 

[Jrejre]

I am not a plumber, but I would think you could have a normal, gravity vented hot water heater if you wanted. However, the cost of running the vent pipe for just the hot water heater is probably not worth it.

Out of curiosity, if you are going to a high efficiency furnace, why wouldn't you want to do the same for your hot water heater?

 

[Sponsor]

 

[Jimbo]

I think you are mixing terminology here. ALL gas water heaters now are sealed combustion chamber. But I think you might be referring to direct vent or power vent?

 

[Gary Swart]

I think you are refering to a power vent type water heater. I don't quite follow the builders explaination however. High effeciency furnaces and power vent water heater that I am familar with vent with PVC or ABC pipe out the side of the house, and they must be separate. I had a high effeciency furnace install several years before I put in a power vent. I just had to run a second vent for the water heater. The length of the vent has been increased with newer models, and I think the new ones do not require 4" pipe.

 

[nellson]

My builder is now agreeable to installing a conventional water heater. Thanks for the inputs; I'm now more conversant with terms like direct vent and power vent. In answer to jrejre, the reason I'm not enthusiastic about a direct vent water heater is that it's a $700 upgrade and about a $1200 replacement cost. I'm of an age where a furnace might outlast me but a water heater is likely to need replacement.

 

[Gary Swart]

I don't know where you got this price information! A high effeciency water heater with a power vent costs no more than a similar size heater with the old fashioned vent-out the roof model. It will last about the same as any other heater, but cost less to operate. It sounds like maybe you contractor is feeding you a line of BS. A power vent heater vents with PVC or ABS pipe very much like a dryer although you don't need the plastic pipe for a dryer. My heater is in a basement and is vented through the side of the house just above the concrete. The furnace vents the same way. Both use 4" ABS pipe. Unless there have been some new techniques, you do have to use separate vents for each appliance, but I believe the newer water heater models allow a smaller than 4" vent.