Which would consume more electric?

heatboy

In a closed heating system using electric as a fuel choice, would I use more electric if I used an 80 gallon water heater as opposed to an electric boiler that only holds 5 gallons. Since I am paying for wattage, it would seem keeping 80 gallons warm would use more wattage than an on demand boiler. The price difference between the two is substantial, with the boiler costing at least twice as much as the tank type. Operationally, doesn't it makes sense that the price difference would be made up in a pretty short time difference.

Electric is the only case in which I believe low water content is a huge benefit. Any thoughts?

hb

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Brian (Tankless) Wood

What temps are

you looking for HB.

If 90-140 is ok, ask HotRod how he likes the "Seisco". This heater modulates between zero & 95,564 btu's without any external controls. Set it and forget it (sounds like Ronco).

Oh, I sell these by the way

Models available are: 9, 11, 14, 18, 22 and 28 KW at 240V.

The two chamber models hold less than 1/2gal, four chamber holds less than 1 gal. The biggest weighs less than 20 lbs!

Let me know if I can help.

Brian (Water heating is a Tankless job) Wood.

Earthfire

depends

on the temps you need for your system and the volumn of water in it.Temps under 125 I would lean more towards the tank . With carpet or wood floors I'd lean towards the boiler with a buffer tank or at least primary secondary piping. As far as electric usage a KW is a KW. I do think that the ratings on tank water heaters are at a 80 or 90 deg delta T wereas in a closed loop we need around a 20 degree make up, So the wattage used should be very close to actual Btu usage.The other factor to keep in mind when looking at payback is the cost of the electricalo wiring and disconnecting means

Dan Peel

Electric systems

With me it's usually a horsepower consideration. On outdoor reset with a low temperature system up to 4.5KW (or the size of your single heater element) tanks work fine. Above that I'm with you - go with a boiler, whether instant or conventional. No vent stack losses and we're still around 9 cents (CDN) a KW here. Enjoy....Dan

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hr

My thoughts

the amount of energy requires to heat the water would be the same. Of course the cost difference would be "holding" the temperature in the 80 gallon tank. Certainly insulation values in the tank and the delta T between the actual tank and room temperature would drive this.

I feel some of the high efficiency electric water heater tanks rival the best indirect tanks for standby loss figures. Essentially 2" of foam around the entire vessel.



Remember those high capacity electric instantanous units require 240 V circuits of 60- 100 amps or more. This may drive your decisions, as there may not be that much "spare" current available. If you go electric instantanous consider the modulating versions like the Seisco.

Keep in mind repairs to circuits boards etc will be much higher than a simple element replacement in a tank type storage heater. I suspect a lightning strike or power surge would be an expensive experienace with a circuit board or microprocessor operated controls found in the high tech electric units, and some electric boilers. Possibly not an "off the shelf" stock item like 4500 W elements and snap disc temperature controls found on electric tank types !

So there

hot rod

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BillW@honeywell

surge supressor

Hot Rod brings up an excellent point. I would strongly recommend a whole-house surge supressor to protect that system (and all the other systems in your house).
They protect against all but a direct hit lightning strike. Must be installed by a licensed electrician, I know of two models, one by Square D, andother by Cutler-Hammer.