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Posted by John Anderson on May 08, 2008 at 02:17:15:
In Reply to: Do high efficiency boilers make sense for baseboard? posted by Tim_Anchorage on May 03, 2008 at 00:40:21:
: I'm looking to replace my gas-fired boiler with either a Weil_McClain GV or Ultra. I'm getting conflicting advice from contractors about whether the higher efficiency of the Ultra is worth it for baseboard applications. Some say that the high efficiency units (Ultra) are designed primarily for radiant heat at lower temps (140) than for baseboard (180+), and as a result their efficiency will not be realized and that they will wear out sooner than GV because it's operating at temps it's not designed for. Others disagree with that.
Tim (I assume in Anchorage)
I'm up in the valley, so roughly the same climate. See my recent post as well. I've likely talked to the same people and got the same advice. And I believe them somewhat. I don't think a mod/con will suffer early death from running at 180F, but you won't net much (if any, the manufacturers get real vague about this and the fall off of efficiency at higher temps) improvement running it high temp. If you can't from space limitations (I certainly can't) add more radiation, and your house doesn't have surplus now (that is a big question, as if your baseboard is oversized perhaps you could run lower temps, mine is not, and is just barely sized, but that is often not the case) then you will likely not see enough benefit to justify the ultra/knight/munchkin, etc insert your favorite mod/con here. Furthermore at least in some regard installing an outdoor reset may net you some of the benefit of running reasonably lower temps most of the year, most contractors up here seem to say even a 15-20% gas savings yearly from just that. As to the GV, I have questions and have found NO clear answers on the web. A lot of contractors up here steer clear of it or the Burnham Revolution, saying that the extra 2-3% efficiency isn't worth the headaches associated with either. If I had to guess I'd say at least the GV has a better rep than the Revolution, excepting the big recall the GV had a few years back. I'm leaning myself to a CGs with outdoor reset, though the CGa or CGi are all within quibling efficiency as are the power vented Burnhams. If you find out any more, post it here.
John