Navien versus IBC boiler?

February 19, 2019 6:07 PM

I am facing the prospect of replacing my New Coke/"We Are The World"-era Vaillant gas boiler and stand-alone water heater. One quote suggests a Navien NCB-E unit and the other suggests an IBC DC 20-125. Can anyone share experiences with either of these units, or compare them?

I am in New England, with existing gas service. Both installers come with positive, recent recommendations from trusted, local friends. Assuming that both boilers are both high-efficiency, and both qualify for the same rebate, what sets them apart from each other?

I have been told that the Navien requires annual flushing by a technician, whereas the IBC can be done possibly less often, and by a homeowner. (That suggests it's a more-robust design, and has a lower cost of ownership.)

The guy pushing the Navien plans to mount a wooden board out from the wall, whereas the guy who likes IBC says that its bracket can go right against the foundation. Do I care?

I believe that both plan to sneak a plastic line up my existing furnace flue and send the exhaust gases there; this is fine by me.

(I know about the delay of an on-demand water heater but that's not what I am asking about today.)

Thanks!

posted by wenestvedt to Home & Garden (5 answers total)

Best answer: We got a Lochinvar combi boiler a couple of years ago. These condensing boilers are great technology, and I’m sure you’ll be happy either way. One key feature is the turndown ratio, which is the ratio between full burn and low burn; the higher the ratio, the lower the “low simmer@ on the unit is, and the more you can save (theoretically). The lochinvar’s was 10:1 across the board, which is pretty good. The Navien has only 6:1 on Heat, but 11:1 on hot water. It looks like the IBC is 6:1 too (20 vs 125). You might ask your installers about those specs.

My heater is on a wooden board. The unit itself might have been installed on the foundation, but there are a number of other things that get installed in tandem, including electrical boxes, clean outs, and circulator pump and expansion tank, and a condensate pump. Having the board makes it all neat and organized.

You might double check on sending pipes up the flue. Mine had to go out the side of the house—since I actually use my chimney. The intake and exhaust are generally PVC, which does not like a lot of heat. Maybe you’re lucky! The exhaust (just steam) from mine vents by my back door, so when the heater is running and the steam is coming out, it can look like an 80s metal concert.
posted by Admiral Haddock at 6:25 PM on February 19, 2019 [1 favorite]

We installed the Navien in our house in July 2018. I never even investigated on-demand heaters, really. The builder we used, uses one plumber (pretty much) and this particular plumber only installs Navien in on-demand houses (a).

To be clear, I have zero experience with the other one and went 100% on our plumbers recommendation. With that said, see (a).

If you have more questions, I can try to get to them here or mefi mail me.
posted by danep at 8:54 PM on February 19, 2019 [1 favorite]

Best answer: I can say from having worked in renovation and also just been in a lot of basements in New England (for my job, so we're talking like a thousand basements here) that almost all the on-demand water heaters you see in New England are Naviens. Now, that doesn't necessarily mean that they're the best—it probably just means that they have a robust sales network and supply chain and that contractors are used to them—but it does mean that plumbers in our area feel comfortable with Navien units as a product. IBC, I have never heard of. Make of that what you will.
posted by Anticipation Of A New Lover's Arrival, The at 3:39 AM on February 20, 2019 [1 favorite]

Best answer: We have an older Navien. Our biggest problem with it so far is that it categorically WILL NOT WORK when we're on generator power due to an outage. We've put line filters on, run it on its own circuit, run it through a surge protector and it just. won't. heat.
Granted, this is a pretty specialized problem, but it is a Thing.
posted by ApathyGirl at 11:24 AM on February 20, 2019 [1 favorite]

Response by poster: Thanks for all the feedback, everyone!

I got very bad interactions with the plumber who was pushing the Navien, and I also heard a colleague bitching about his Navien (literally saying "I will never buy this product again") -- so I think we're going to avoid those.

Now, if you will excuse me, I have to go sell a kidney to pay for my new boiler....
posted by wenestvedt at 1:42 PM on March 22, 2019