High efficiency

Frankcreo_777

High eff. 94 afue direct vent hot water gas heater in an unheated crawlspace? Pa zone 4 sometimes 5 lol

Jamie Hall

And... ? Is this a water heater application, or a boiler?

mikeg2015

It’s a bad idea to put any HE system in an
Unconditioned Space as
Drains can freeze. But is this a mostly sealed or vented crawl? Does
It have exposed water lines already?

Frankcreo_777

Its a breezy wet drit space. Single longest copper line freezes onec or twice a year uninsulated. Just installed a rinnai gas tankless water heater with pex and its heavily insulated. Fingers crossed. 20 yo steam slant fin with dhw crapped out last year. A wall mounted hot water baseboard set up it a bit riskier for the work/money investment.

Frankcreo_777

Jamie. Already did a hot water tankless. This would be its first winter. Aiming for a boiler baseboard switch. Can enyone speak to the efficiency of hydronic baseboard over steam? Half? I have a very small 700 ish sq ft house.

Jamie Hall

Two in one day. Sigh... assuming equally modern, equally well installed, controlled, and maintained steam and hot water systems, the maximum efficiency of a steam system will be around 86%. If the hot water system is powered by a mod/con, it can, under certain conditions, reach as high as 96%, less pumping losses -- but only under certain conditions.

I would expect that on the whole, the best you could expect from a hot water baseboard system would be that it might reach 5% more efficiency than a steam system. In hard numbers, if a steam system burned 950 gallons of oil in a year, one might expect the mod/con to burn 900 -- a 50 gallon difference.

Zman

If you are looking for feedback, you may need to slow down a bit.
Have you removed the steam yet? What is/was wrong with the steam system? Have you considered improving the insulation and air sealant in the crawl space? What type of boiler are you considering for your conversion?

JohnNY

In a 700 sq ft house, it's not going to pay back in any appreciable way that would attempt to justify its cost. However, if you want the control and flexibility of a hot water heating system which would for some reason work better for you over that of a steam system, then that would be the only reason to convert to hot water.

Frankcreo_777

Zman. It was a 25 yo slant fin. Cracked with water pouring out. Not gone yet. If i switch to hot water i can do most of the prep myself via pex and hanging the wall unit and a 1500 credit from the gas co. Fir a unit 94 afue or greater. Hopefully savings as well in the long run. If i stay steam its more expensive, no credit, no savings and its out of my hands. Even if i can prep to cut costs by breaking up and removing the old unit theres no way im getting a new unit into that crawlspace. Wouldnt be safe for a noob. I cant afford to condition the crawlspace professionally. Its a dift/ wet space with a pump. 3 sides cinderblock foundation. One wall stacked stone very loosly with lots of spaces. I laid vapor barrier on the ground and sealed as many holes as possible. Not as bad as direct wind but def freezing.another vote for steam in my mind is the warranty on a decent steam unit as opposed to a wal mount high eff boiler. 25yr? on slany fin galaxy at a good price. Thoughts?

Jamie Hall

I'd still stay with the steam... even with the ratepayers paying part of the bill to change, I doubt that you'd really save much money -- if any. Especially if you have to add radiation to compensate for the lower output of hot water.

hot_rod

did you run a heat load calc? That would help define what you need for emitters and boiler size