hot water

[kirkcudbright]

We've been without heat or (more importantly) hot water since yesterday morning. We have oil heat with an indirect water heater - the boiler provides a heating loop into the water storage tank. The overall problem is that there's no water in the boiler. This is the result of 2 actionable problems: 1) the feeder valve is broken, so no water is getting into the boiler, and 2) there's a blown gasket at the boiler outlet, so any water that did get into the boiler immediately exited stage left onto the floor.

We've been talking about converting to natural gas (but haven't started the process yet), so don't want to spend any more on the old oil burner/boiler than we have to. This led to a deep dive down the rabbit hole of "should we convert to an electric tankless water heater now, and live without heat until NGrid can hook us up?" Alternately, if we fix the oil system for now, should we consider a gas-fired tankless heater when we convert?

There's a lot of factors in play here: equipment costs, installation costs (including possibly ugrading electric service or gas service), operational costs, correct sizing, etc.

There's a *lot* of information and mis-information out there, but if you're interested, these are a reasonable overview:

• EnergyStar.gov white paper Electric Tankless Water Heating: Competitive Assessment is nuanced and ultimately non-judgemental.


• This Old House breaks down the 20-year life-cycle costs (and provides the only hard numbers I've found on the operating costs for an electric tankless heater). They feel that a gas tankless heater is worth it in the long run.


• Consumer Reports comes up with slightly different numbers (based on a comparison of two tankless heaters and three conventional heaters), and concludes that the operating savings don't offset the higher up-front costs.


• Musings of an Energy Nerd agrees with CR, calculating the simple payback period at 21-35 years.

Old House Web also likes the sort of indirect heater that we have now, because (they say) it has the lowest life-cycle costs. It's certainly simple, but I'm not keen on firing up the boiler in the middle of the summer to heat up a bunch of water, to heat up a different bunch of water. Then again, our zone valves are flaky, and often end up sending water to the baseboard heaters in the summer. Something else to fix when we re-do the heating-related plumbing.

With electric tankless out of the running, the short-term plan is to fix the oil system, and defer the question of indirect vs tank vs tankless to when we convert to gas.

Comments

[lyonesse.livejournal.com]

might you want tankless for some particular local service? it's been awesome for and/or's 1st floor bath with the giant tub.

i had tankless at the pond house too, but it froze and died b/c basement and disuse :/

[kirkcudbright.livejournal.com]

might you want tankless for some particular local service?

Actually considered it for the master bath, but it would also require a new 220V run (vs 2 or 3 new runs for a whole-house electric), plus plumbing and carpentry. (Or a 2nd floor gas line and vent, when we get plumbed for gas.)

i had tankless at the pond house too, but it froze and died b/c basement and disuse :/

I remembered you had taken out the tankless, but I'd forgotten why. Our basement gets enough heat bleed from the upstairs and the oil burner that we've never had to worry about freezing pipes.

[lyonesse.livejournal.com]

hmm, i did a 220 run to my third floor kitchen at and/or (for the dishwasher i have yet to install) and honestly it wasn't really a big deal. (you will note i haven't done the carpentry or plumbing yet, either, though.) though conceivably you could also just put the heater in the basement and isolate the relevant plumbing? that's how our first-floor master bath works, the old first-floor tank still supplies the first-floor kitchen and the laundry room. (it was a desire to not compete with the laundry that inspired me to install the tankless in the first place.)

the tankless at and/or has always been fine, but its basement coexists with the half-dozen gas-fired appliances and heat leak from upstairs as well.

[solarbird]

I took our sidearm water heater out, replacing it with a separate oil-fired water heater (so still using oil), and our oil use dropped 30% from that alone.

As far as I can tell, they are never worth it.

[kirkcudbright.livejournal.com]

Hm, interesting. a) Wasn't aware of oil-fired water heaters as an option. b) Surprised you saved that much, but c) You're in a slightly more temperate heating zone than New England.

But our long-term plan is most likely gas+gas (plus un-fucking the plumbing), so too many variables to compare.

[solarbird]

It's murkworks south, so a lot of building and a lot of people both. So not really comparable, I guess. But yeah: hugely inefficient. And it made the front half's living room a lot hotter in the summer, and not having that around anymore was great.

Still, I don't recommend oil hot water - unless you're an apartment building, it's not worth the cost. Even we're borderline. I'd like to figure out how to replace it with natural gas.

[deguspice.livejournal.com]

We have an oil burner that provides hot water to heat our hot water tank. We usually go from April to October on just one tank of oil . One advantage of having the boiler proving the hot water during the summer is that the boiler is in use year round, so you don't get surprised in the Fall when you turn on the heat for the first time.

If you're looking to have someone replace your boiler, I recommend Ed Grant of Grant Burner Service in Haverhill. He specializes in boilers (steam and forced hot water systems). During the summer he's willing to travel further.

http://heatingrepairhaverhill.com/

[electrictruffle.livejournal.com]

In addition to the additional 220 circuits that you would need to run, a whole house electric demand heater might require an electric service upgrade. These things use so much power that internally you need multiple 240V circuits.

Say you want 2 gallons per minute at 120F with 40F water coming in. You need 23.5KW, or about 100A at 240V. I would not install a large electric demand heater without a careful evaluation of the electric service and of the transformer supplying the service. I have heard stories about demand heaters making the lights flicker at the neighbors houses.

I also have 1 complaint about gas demand heater for the andor huge tub: I liked to take long showers with the water flow rate turned way down. I learned the hard (or cold) way about minimum flow rates. But it was sure nice for _filling_ the tub.

-ETR

[kirkcudbright.livejournal.com]

The tankless electric heaters we were looking at say up front that they require 2*60A or even 3*50A. We do have 200A service, but it was one of the things that gave me pause.

[pywaket.livejournal.com]

Yeah, it's hard to get a shower cool enough in the summertime. I end up sometimes having to turn on both showerheads just to get a high enough flow rate.

[zahraa]

zyxwvut and I put in a tankless heater last year. Ours didn't cost more than my mother paid for her tank heater, and my mother is a big bargain-hunter. It's great; you can have as much hot water as you want. It does take longer for your shower to get hot, because it has to get started heating the water before it starts sending it to the back of the house. Since we're in drought conditions, I've been collecting the not-yet-hot water in buckets and using it to water plants. I'm getting so buff carrying the buckets around.

[kirkcudbright.livejournal.com]

Hm, we're not green enough to collect not-yet-hot water. OTOH, while they were working on the water mains last night, we carried in buckets from the rain barrel to flush the toilets.

[zahraa]

Well, we put in a dual-flush toilet last year. But we don't have enough rainwater to collect. :-(

[pywaket.livejournal.com]

A lot of commercial installations use drain heat recovery systems to preheat the water using the waste heat. It might make an instantaneous electric heater more feasible for you.

http://energy.gov/energysaver/articles/drain-water-heat-recovery

http://www.renewability.com/power_pipe/index.html

Agent Orange is even selling them now: http://www.homedepot.com/p/Power-Pipe-2-in-x-60-in-Drain-Water-Heat-Recovery-Unit-R2-60/203455947

Payback time is estimated at 2-10 years by Environment Canada. They're apparently quite popular up there.

[zahraa]

The system we have works reasonably well. It's just slower than a regular tank heater and thus allows us to recover a fair amount of water. The water heater is gas.

[pywaket.livejournal.com]

Oops, sorry, I meant that for Paul.

We have a gas tankless here at Andor as well. It works really well.

BTW, I've seen systems where there's a separate valve to allow you to effectively "turn on" the hot water, but it just feeds the water back into the cold supply. It allows you to run the water to get it hot without wasting any. It's fairly easy to plumb, just requiring a return line, an anti-backflow valve and a valve to turn the system on.

[zahraa]

That would be kind of cool, but you wouldn't believe the pecs I'm developing carrying around 32 lbs of water at a time. I think I'll stick to the current system for now.