Posted on 04/29/2019 12:56:12 PM PDT by ProtectOurFreedom
Does anybody have experience with "Power Direct Vent" water heaters? I need to replace our conventional natural draft water heater and am thinking about a Power Direct Vent model. These units have a sealed combustion chamber and take outside air via a PVC pipe for combustion and the send the combustion gases outdoors via another PVC pipe.
I've read that the fans and burners on PDV water heaters can make a lot of objectionable noise. The fans make noise especially when starting up and the burners can make a loud rumbling noise.
Our forced air furnace is a similar design with a sealed combustion chamber and the coaxial pipe for air inlet / flue gas discharge. I don't hear the exhaust fan or burner rumble noise from the furnace.
I need to switch to a sealed combustion water heater as part of an energy retrofit program to prevent future ice dams in the winter. We had terrible ice dams this winter (North Idaho, Climate Zone 5) leading to water getting into the walls and buckling a small part of our newly refinished floor (nothing hurts like seeing your beautiful newly refinished floor buckling!)
In looking into the problem, I've found a lot of root causes for the ice dams - inadequate attic insulation (bare ceiling sheet rock in places!), inadequate attic ventilation, no air sealing between the house and the attic, and a utility room dumping a lot of warm air into the attic which melts roof snow.
The existing water heater in the utility room is installed per code and has two combustion (fresh) air inlets, one in the ceiling (communicates to the attic for air) and one in the floor (communicates to the crawl space for air). This creates a perfect convection path where cold crawl space air enters the utility room, is heated to 50F to 70F, and then flows into the attic where the warm air melts the snow leading to the ice dams. By switching to a Power Direct Vent water heater, I can close off the floor and ceiling vents and stop all the heat in the utility / mechanical room from flowing into the attic.
But these Power Direct Vent water heaters are expensive and I'm concerned about the possible noise problems.
The energy savings will never pay for this upgrade, but it's really important to stop the ice dam problem.
You are buying a new water heater because of that? Reroute the pipes, install a fan, ventilate the attic, install attic floor insulation, etc. All of those things are cheaoer and have better payback.
I have a “tankless” heater than runs on LNG and I love it. Never run out of hot water and faiy cheap (in PA) to run.
If it were me, I’d look into one of those on-demand, tankless, endless hot water heaters.
PVC for intake and exhaust gases?...................
I don’t know anything about this brand.
What I do know is that water heaters can go bad and leak and can flood the house, so it is best to put them outside, not inside the house.
One of the first things I did when I bought my house was to move the water heater outside.
I’ve had one for fourteen years. Natural gas fuel. EFFICIENT. Has needed no repairs and is still going strong. The cost over a standard gas hot water heater, as I recall, was about 30% more, but the higher efficiency paid that premium in the first three years or so.
You are talking about ventless water heaters. Yes, they work using nearly all the heat to heat the water. But gas water heaters today have very thin tanks that will only last 3-5 years. Consider getting a tankless water heater. More expensive up front but they have a much longer life.
Solution:
Move to Florida...................
My last WH installation was a gas-fired tankless (on demand) water heater. But I’m not familiar with DPV.
It is mounted on the inside of the outer wall of the laundry room and the exhaust vents straight through the wall from a foot-or-so long insulated pipe. Takes up very little space.
Saves gas since it heats on demand, but maybe a few seconds slower to get hot than from a tank that’s already heated.
One of the first things I did when I bought my house was to move the water heater outside.
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You don’t live in Minnesota
Hi.
“Power Direct Vent” water heaters?”
First let me say I’m not experienced or an expert on water heaters.
But, depending on where you live, quality of water you have to flush and drain the water heater every two or so years.
Good luck.
5.56mm
If your hot water vents to the attic, consider insulating the pipes. Code calls for R-8 on duct pipes in uninsulated spaces. Not sure about for vent stacks.
I would think though, with proper air sealing and insulation, that would solve the vast majority of your problems.
If you’re thinking of doing this yourself, PM me. The company I work for makes some good products for air sealing attics and I’ve got a decent level of knowledge of the job.
Get a tankless, I love mine.
My new Florida home has a natural gas-fired Rheem unit mounted on the outside. We love it.
We got a new system that has a much smaller tank but heats the water to a much higher temperature. The very hot water mixes with cold as it exits the system. Much more efficient since far less water is kept hot. We saw good savings.
Solution:
Move to Florida...................
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But then there’s the need to invest in such very strong perimeter defenses to safeguard against wandering groups of Florida Man.
They require stainless steel exhaust outside vents, and aren't cheap going in, but mine paid back in 5yrs, and the previous one I had at my nursery for the office bathroom, in 1990, worked for 22 yrs.
I saw it on "This Old House", spent weeks getting one of the very first models, from Oregon. and it worked beautifully. The new systems are amazing.
Ditto the vent to the crawl space, although fire doesn't normally go down as quickly as it goes up.
There should be a makeup air vent from the outside to a dampered box near the water heater. It allows air to come in, but doesn't let (much) air out, so it's not blowing your expensive heated air to the outdoors.
Block off the attic vent, keep the crawl space vent, and replace your water heater with another conventional gas 40 (I have a 50) gallon water heater and call it a day.
The power direct vent types have a much cooler flue gas, which requires the fan to push the exhaust out of the house. They're fine for new construction, and are more efficient, but are much more expensive to buy and can be MUCH more expensive to retrofit. Spend the money on more attic insulation instead. That will pay for itself year round if you both cool and heat your home.
Also, look for bathroom ceiling vents that blow directly into your attic. Those should also vent to the outside, but older homes just had them blow into the attic, which can also be a source of warm air that causes ice dams.
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