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.