Radiant Heat Loss

Nick_16

I did a radiant heat loss calc on my home and at came out to 56,781 for my first floor, basement, and garage. (Baseboard in basement & garage.) Total of about 2500 sq. ft. I have a tight house and fully insulated garage. House has R-48 in ceiling, R-4 in walls, double pane windows but not very many, fully insulated doors and weather sealed windows, etc. Garage has R-30 in ceiling and R-4 in walls. Total system will have several zones. As we all know, there is almost never a time in which all zones call for heat at the same time. Even on the coldest day of the year. The electric boilers I am looking at come in 51,000 and 61,200. So should I size up or down? That's the BIG questions! LOL We all know it bad to oversize but you don't want to not have enough heat either. Is there a way to modify the heat loss calcs to account for zoning? Please let me know any thoughts. Thanks for all of your help!

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Most electric boilers

step the elements on anyways. I'd go over a bit, price doesn't change that much from size to size.

Look at the required breaker and wire size when you jump up sizes, however.

I used a Thermolec electric boiler from Canada. It had a built in outdoor reset control. Nice and quiet, smooth running machine.

Some of the older technology versions still use those loud contactors the clack like geese eating dominos. Lots of contactor point maintenance also.

Newer versions are all microprocessor controlled. here is a view of a Siesco I'm experimenting with. 14KW from this 10 X 20 box that weighs about 10 pounds!

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Nick_16

Thanks

Thanks for your input. Wire size and breaker not a problem because I have 200 amp service and have up to about 90 amps left over. 15 KW should only take about 65-70 amps when all elements are on. So, because the elements cycle on and off with how they are needed, I shouldn't run into short cycling if I go to the little bit bigger one?

hr

When I first ran that Seisco

I clamped my amp meter around the supply wiring. It would ramp all over the place. From a low of 5 amps up to 28 amps draw. I don't know that it ever shut down completely during a heating season.

No noise, no lights flickering as is possible when large contactors slam on, etc.

Also the electricians around here wire two seperate 30 amp circuits with #10 wire, instead of a large 60 amp circuit. Makes wiring to that small circuit board much easier.

Make sure they label BOTH breakers, however. This way a repair contractor will know to kill both circuits before servicing. Around here they provide those knife type disconnects right next to the electric boiler. Much safer for maintenance that way.

Look for a modulating, outdoor reset electric boiler would be my advice. Plenty of them on the market these days. Most started out as instantanous electric DHW heaters.

Watch out for listings if that is an issue in your area. I buy the ones that are listed, and approved, as a heating boilers, not instant water heater. The control logic in the processor is a bit different, I believe.

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