How Noisy are Power Vents

AdmiralYoda

In the spring I'll be in the market for a new water heater.  I'm on the fence between a gas hybrid heat pump or just a good atmospheric gas water heater with a damper.

I've never had a power vent before which I assume the hybrid units have.  I've heard a few comments that power vents can be loud.  That true?

ethicalpaul

The hybrid water heaters don't use gas. They are a hybrid between electrical resistive heat and the heat pump.

Jellis

@ethicalpaul is correct, a "hybrid" water heater uses A heat pump as well as electric coils to heat the water.

I highly recommend the hybrid heat pump units... a few things to keep in mind.
They cool the air around the heater by removing heat from the air and pumping it into the water this results in a noticeably cooler area around the heater. In turn they also de-humidify so you will need a drain for the condensate to collect.

AdmiralYoda

Haha....you're right.  Brain fart.  Thought one thing and wrote another.

I was referring to the high efficiency gas water heaters with a power vent.  Tanked, not tankless.

I'm wondering how noisy those are.

ChrisJ

No idea how loud a hybrid heatpump is, but a gas power vent isn't terrible.

It's not silent like an atmospheric water heater but it's not bad either. I'd avoid putting it directly under a bedroom if possible unless you sleep with a fan on.

AdmiralYoda

Thanks @ethicalpaul and @Jellis.  I'm considering all options.

I'm in the Northeast and gas is cheaper than electricity...but I'm also after efficiency too.

So that being said, I'm considering a hybrid electric unit, a high efficiency gas with a power vent, and a good atmospheric with damper.

Tim Potter

My Daughter has a power vent water heater, You can hear it, but its quitter than the Gas furnace that it sits next to, if that gives you any reference, its a small motor used for the vent blower.

PerryHolzman

My experience with these kinds of things is that it depends on how much $ you are willing to spend on the power vent. Quite ones cost more $.

My wife was stunned how quite the new bathroom vent fan I installed for our one bathroom. You can barely hear it running - and only if there is no other noise in the house at all. Of course, it cost several times more than most bathroom vents... But, well worth it.

Try to find some noise ratings... It matters in most applications.

ps: If anyone is interested: It was an inline duct fan (and any original vent fan in a mid 1950's house is rare). I replaced it with a Panasonic "Wisperline (TM)" 240 CFM fan (Model FV-20NLF1).

Jamie Hall

There's another consideration: recovery. Heat pump units are slow... and if they are asked to recover quickly, they go to resistance heating. If I had gas, I'd go power vent gas every time.

ethicalpaul

I'm in the Northeast and gas is cheaper than electricity...but I'm also after efficiency too.

I'm in the NE too. It doesn't matter. Heat pump hot water is cheaper regardless.

and if they are asked to recover quickly, they go to resistance heating.

If you let them, they can. I don't let mine.

AdmiralYoda

Ah crap.  For some reason I thought power vented gas water heaters could share the same flue as my steam boiler.

Looks like they all use PVC and can't share flues.

So it really comes down to an atmospheric gas with a damper vs an electric heat pump water heater.

AdmiralYoda

I'm really leaning to a heat pump style for a couple of reasons.

First....in the dead of summer my basement gets a little musty.  It's a crawlspace that needs a new liner but that's another story.  I like the idea of the basement temperature being a bit lower as it will prevent that musty smell until I fix the liner.

It will also take some load off of the dehumidifier in the summer months.

Lastly, we are having solar panels installed as soon as weather permits and we are expected to have an overage, where the electric company will cut is a small check at the end of the year.  That electricity overage can pay for the heat pump water heater.  In other words my solar panels will pay for the hot water.  (Sort of)

mattmia2

The traditional power vent water heaters are not more efficient than the atmospheric water heaters, they just can vent with PVC. The one I had from about 2001 was extremely loud, you could hear it throughout the house. HTP has some high efficiency direct vent water heaters that would be worth taking a look at. They are also stainless so if your water chemistry is compatible the added life could justify the cots. Even with the electric resistance heating the recovery of a gas water heater will be faster than the electric hybrid.

ChrisJ

mattmia2 said:

The traditional power vent water heaters are not more efficient than the atmospheric water heaters, they just can vent with PVC. The one I had from about 2001 was extremely loud, you could hear it throughout the house. HTP has some high efficiency direct vent water heaters that would be worth taking a look at. They are also stainless so if your water chemistry is compatible the added life could justify the cots. Even with the electric resistance heating the recovery of a gas water heater will be faster than the electric hybrid.

The standby losses from a power vent heater are substantially less than the typical atmospheric heater (without damper).

Back in 2011 when I had looked I don't think I was able to justify the cost increase of a damper vs no damper atmospheric heater.  I wanted a normal atmospheric heater but vent issues made it simplier to go with a Bradford White 50 gal power vented heater.  

Saying you're concerned about efficiency is fine but if that's the case you need to include generation and transmission loses as well if you're going electric.  Including solar into that is above my pay grade.

But without solar there's absolutely no way I'd choose a hybrid heater over gas especially a cheap atmospheric heater.  I've had this argument with Paul many times.  He's certainly allowed to have his opinion even if it's wrong 😂

JUGHNE

The power vent water heater look to be efficient because of the PVC venting, you think anything with PVC venting is not losing much heat. However the exhaust fan adds air from the basement to cool off the gases. So when running it is pulling air out of the house....maybe more than standard burner? IDK.

ChrisJ

JUGHNE said:

The power vent water heater look to be efficient because of the PVC venting, you think anything with PVC venting is not losing much heat. However the exhaust fan adds air from the basement to cool off the gases. So when running it is pulling air out of the house....maybe more than standard burner? IDK.

Normal burner adds air via the draft hood.

mattmia2

So it reduces standby loses somewhat but it also sucks more heated air out of the house than a natural vented water heater. It is a little more efficient, but the heat transfer is still lousy and it will still draw some air through the center of the tank which is still unisnulated.... I wouldn't choose either for efficiency, I would choose them for whichever is least expensive to install.

ChrisJ

mattmia2 said:

So it reduces standby loses somewhat but it also sucks more heated air out of the house than a natural vented water heater. It is a little more efficient, but the heat transfer is still lousy and it will still draw some air through the center of the tank which is still unisnulated.... I wouldn't choose either for efficiency, I would choose them for whichever is least expensive to install.

See my comment above.

mattmia2

The draft hood adds less air than the power vent does, the power vent adds enough to dilute the flue gasses to a temp below that which PVC is rated for. The draft hood leaves the flue gasses at a few hundred degrees. If the tank is in a basement and the pvc exits out a sidewall or even worse a roof or really up anywhere, the vent will draw from the heat in the house and the water.

ChrisJ

mattmia2 said:

The draft hood adds less air than the power vent does, the power vent adds enough to dilute the flue gasses to a temp below that which PVC is rated for. The draft hood leaves the flue gasses at a few hundred degrees. If the tank is in a basement and the pvc exits out a sidewall or even worse a roof or really up anywhere, the vent will draw from the heat in the house and the water.

So I guess the deal is if you don't use a lot of hot water a power vent is better.  If you use a lot an atmospheric is better.   At least out of those two.

I'd like to see actual test results between the two though.   I'm betting the PV still wins over all in normal use.    I'm sure it loses ultimately if you include purchase cost.

JUGHNE

Biggest advantage IMO, is no chimney thru the roof.
If new FAF or boiler goes out thru the wall, that leaves the WH as an orphan. Often stuck into an oversized potentially unsound masonry chimney. I see that a lot here.

I have chosen ModCon boilers over standard CI based solely on very bad, impracticable to repair or re-line, masonry chimneys.

Jellis

Currently in Maine there are very lucrative rebates for the hybrid water heaters also. Not sure about the rest of the north east.

AdmiralYoda

@Jellis in MA there are rebates up to $600 if you are replacing an standard electric or propane tanked water heater......but not when replacing an atmospheric gas heater like I have.

There is a $300 federal tax credit and a $150 credit from the electric company though.

The second I wrap up installation they will probably offer the $600 rebate again.