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We have a high-efficiency furnace. Two pipes are coming outside the house as expected. However, right now, there is at least 2 feet or more of extra PVC on the exterior showing.

Is there any harm in removing this extra length for cosmetic reasons? Also, what is best to use on the endcap to prevent debris, etc. from entering? I have seen these triangular looking endcaps, but not sure of the name.

There is an overhang above the pipe. I'm guessing 1.5 - 2 feet.

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up vote 2 down vote accepted

The pipes have to be long enough to clear any overhang or roof.

This is to ensure that the exhaust gases don't collect under the roof. This could be a fire hazard (if the gases are hot), though this isn't that likely, or a health hazard (there'll be high concentrations of CO2, or even CO, in the gases. If these re-entered the house it would be a definite health hazard.

There could also be a lot of moisture in the gases and you don't want that condensing on the overhang either.

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That makes more sense. Also, the pipes are bent once they protrude from the house. Any ideas? Is that so water doesn't flow back into the pipes... Thx again. – tjg184 Mar 1 '12 at 14:18
@tjg184 - probably. That's where end caps come in useful as well. – ChrisF Mar 1 '12 at 14:27

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