Nat Gas Alternative to Electric Boiler (Thermo 2000 Mini Ultra 3)

evelyntoronto

Thanks in advance for your perspective! We're installing a radiant in-floor heat system in our basement (~500sf). Our HVAC specialist suggested a compact, efficient, cost-effective electric boiler, the Thermo 2000 Mini Ultra 3, to run the in-floor heat, which we love the idea of. That said, we're now realizing we might need to upgrade our electrical panel to accommodate, which we'd prefer not to do. Any suggestions on units similar to the Thermo 2000 but powered with natural gas? Hoping there are advisable options from Rinnai or Navien, given our familiarity with those brands, but open to all thoughts. Thanks again!

ethicalpaul

I hope people can give you a good alternative because although electric resistive heat is 100% efficient, it is also very expensive unless you live in an area with excess cheap electric power such as near a hydro plant. As you have seen it takes a lot of electricity to create heat.

Jamie Hall

That's kind of a tough one. Given the size of your basement, there's no way that you can push more than about 15,000 BTUh through that — 5 kW or so. That's at the low end of any fuel fired boiler I know of.

It's also not that much electricity. Unless your electrical panel is really weak, I'd be rather surprised if that couldn't be accommodated. The 3 version you mentioned only requires a two pole 20 amp breaker. Surely you have room for that?

All that being so, I'd go for the electric one…

Hot_water_fan

That said, we're now realizing we might need to upgrade our electrical panel to accommodate, which we'd prefer not to do.

are you sure you need to do this? That boiler is only 3kw.

A 500 sqft basement should have a remarkably low heat loss. I think 2500-5000 Btu is entirely possible, which no gas boiler will be able to handle cost effectively.

A different route would be to use an existing domestic hot water heater to heat the space using a heat exchanger. This would make the most sense to me if you have an existing tank. If no existing tank, you can get a tank with only a 1kw element.

IMO the key for this project is not to spend too much chasing efficiency and find the solution that lets you use the existing panel.

GroundUp

As others have said, electric is almost certainly going to be a better option than NG here since nothing turns down that far and remains happy with it. That 3kw unit only draws 12.5A at 240V but if you really don't have space in the panel for a 2 pole breaker, you're kind of stuck unless you go to a 120V unit with a single pole breaker. Electro makes a 2.5KW boiler with a 120V element (I just installed one today, as a matter of fact) but the amperage is 21 due to the lower voltage. Perhaps something like Hot water fan mentioned, a small water heater tank with a 1-2kw element or connecting to the existing DHW system with a heat exchanger. What is the actual concern with the electrical panel? The upfront cost of any NG boiler is easily going to be higher than upgrading the panel, unless there are some extenuating circumstances.

Hot_water_fan

Another option would be to ditch hydronics entirely here. You could use an electric mat, avoiding all water, or use an electric baseboard.

evelyntoronto

Thanks for weighing in, everyone. A lot of confirmations here of what I had been thinking (i.e., panel shouldn't be a limiting factor), so super helpful, and it's clear what I need to do next. Thanks again!