Options: Electric Radiant

Al_10

We are starting to plan a new 2000' home in Iowa. Our only heat option is Electric Radiant. I want to get some unbiased information from you guys before going to a HVAC contractor. I want to know if the contractor is packing my vent pipe.
2x6 walls, sprayed foam, energy truss, low E glass, slab on grade, no floor coverings, simple ranch. Very basic.

Which would be best and/or most economical to install and operate?

1) tankless water heater
2) electric boiler
3) geothermal heat pump
4) other?

DHW will be completely separate.

The only work on this heat system I plan to do myself is write the check. :)


We are at .05/kw 9pm to 4pm and .13/kw 4pm to 9pm. We will put the system on a master timer to avoid peek rate.


Thanks,

Al

kevin coppinger_4

why would Electric...

be your ONLY choice? LP or oil not available? Orbitz is a good choice for the wire if you did do the wire...I have a friend who has done it and it came out well...Insulate very well downward and on the perimeter...kpc

Dan Peel

Electric options

Look hard at the geo thermal option - a little more cost on the way in but nice low operations cost in the right design. In our current (local) pricing fuel costs are top to bottom - LP, electric, oil, natural gas - without a great spread between any of them. Electric boilers are still a viable choice here in Southern Ontario too. Enjoy...Dan

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hr

crunch some numbers

first off a heatloss calc and design would be a must. That will determine the amount of heat you need.

Suppose you calc out at a load of 50,000 BTU/ hr needed.

a 15KW boiler would get you close. Multiply the 15,000 watts times the KW price. At .07 ( the low side figure) that would be $1.05 per hour to run the boiler.

A 60,000 BTU boiler, running 90% efficient, burning lp at $1.05 per gallon would get you about 1-1/2 hours of heat

I'll bet geo with a large buffer to take advantage of the off time would pencil out the cheapest electric powered system to operate. It could also provide cooling. If in fact electric is the only source this may be best. Up front cost of the geo need to be looked at

All in all a modulating, high efficiency boiler on LP would probably be less to operate, for heat and dhw. Regardless of the time of day Possibly less to purchase and install than a geo system. It could easily provide heat and hot water. Is LP an option? It must be available nearby?

hot rod

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Mark Eatherton1

If electric is all you've got...

then I'd go with 1/2" tube, and an electric boiler. The GSHP is going to cost the least to operate, may qualify for energy credits from certain co-ops, and if properly done can provide you with cooling too.

The reason for using tube versus wire is that if the tube breaks, you can find it and fix it. Pretty slim chance of it actually happening.

If it's wire and it breaks, there is no way to find the break, and even if you did, it would be tough to repair.

I know, I know, there are parallel grids out there, but their still like a light bulb. They go out without warning. And when they do, they're impossible to repair.

At least with the tube you can "see" it with infrared, and they make repair couplings...

If I were going to do it, I'd oversize the equipment some, pour a 12" super insulated slab, and put a timer on it to coast through peak demand periods. You could knock the snot out of your utility costs and maintain the most comfortable conditions you could possibly have. And it will interface with solar thermal quite well...

Just make sure you use qualified contractors for both the radiant AND the ground source.

You can find I.G.S.H.P.A. certified contractors adn R.P.A. certified contractors on the net.

That's how I'd do it if'n it were mine.

ME

Mark Eatherton1

G.S.H.P. $

works out to $0.58/Therm. That's the cheapest you're going to find per hour to operate. The initial hit is still there, but worth it in MHO..

You can justify the $ differential with the $ savings differential and pay for it in short order.

ME

leo g_63

aarrghh!!!

what drives me crazy about electric boilers is that the ones that we have installed all have 3 stages. yet none of the manufactures that i know of have incorporated an outdoor reset-like control into them, ie like a good gas condensing boiler. can you imagine an intelligent control, deciding which of the stages it should be heating at? instead it seems that we are stuck with this ancient style of measuring the return water and not even intrigrating where the boiler temp thermostat is set at.

watching these electrics that we have installed, it is very rare that the boiler just heats on the first stage, even on a "warm" day!

i tell you, we are looking at a project where there could possibly be as many as 700 homes, all heated infloor with electric boilers, if some smart manufacture would apply the existing technology, i know where i'd be shopping!!!!

leo g

Mark Eatherton1

Whats wrong with tekmar...

they make a multiple boiler control that I'm sure could easily be integrated into the control logic of most electric boilers I've seen.

Good to see your words my Canuckian friend!

ME

MikeB34

Argo

Makes an electric boiler and outdoor resets. I would think them compatible.

RobertUnderwood

prof

i checked with our local boiler manufacturer, they said that it could be done, but the boiler would no longer be CSA approved, nor would it have their warranty anymore. i then asked if they had considered maybe teaming up with tekmar to build this boiler and get CSA approval, "why? we're quite happy with our sales as they are, besides, do you know how much it costs to get something CSA coded?"

the thing is, is that i really like these guys, because they are local, and respond to problems, usually within a day, but i have been moving our purchases away from them because of this attitude!

yeah, i have been spoty on this site, lots going on, mainly shutting down the plumbing end of the biz, and going fully hydronic, exciting/scary times right now! how's the shoulder doing?

leo g

RobertUnderwood

thanx mike,

i'll see if i can find their web.

leo g

hydronicsmike

All Multiple Boiler Reset Controls

...are compatible as long as the boiler has contacts for each stage.

Leo, when are you coming to visit us? A couple of hours drive will get you to some of the nicest ice fishing areas in the world.

mph

Electric boiler control

Why not use a tekmar 260 Boiler Control? You get full outdoor reset and no mixing of any kind required. Does it really matter if all of the stages come on? The contactors are probably rated for millions of cycles and that's really the only thing on the electric boiler that's going to wear out from short-cycling.

Jeff

RobertUnderwood

vernon

mike, my brother and his family just recently moved back to vernon, but i doubt we will be visiting in the near future, but when we do, i'll let you know!!!!

then maybe you can show me how to wire up one of these boilers!!!

merry christmas to you and yours!!!

leo g

RobertUnderwood

jeff

i have used tekmar on these specific boilers with not very good results. it seems that the boilers "logic" is that if the return water is not coming back "hot" right away, then it jumps to stage three, kinda defeating the whole purpose of three stages!!!

leo g

hydronicsmike

Thanks Leo

Wish you and yours all the best for the holidays. Simply call before you're in the area, or, drop me an email. We'll do lunch or dinner.

mph

Leo

I was under the impression that the only reason for staging the elements was so there wouldn't be a huge power surge when the boiler first fired, not to gain any efficiencies. Whether you use 4kw or 12kw to heat the water, it's going to net out the same, because the boiler water temp is only going to get as high as the tekmar requests. At 12 kw you'll just have shorter "burn" times.

Jeff

Mark Eatherton1

The shoulder...

is doing well, thank you. If you have any questions or need any help on going fully hydronic, let me know. Congratulations!

ME

Al_10

Thanks for all the input. I'm going to get with the local electric coop to see what incentives they are offering on Geo. Geo has more up front cost, but we will be in this house for at least 30 years, so I'm looking at the big picture.
The reason I was thinking about the electric boiler was because a builder thought the house would be so energy efficient that a geo system would be over kill.
Builder thought the break even point would be a long time away. It's only a 2000' ranch.


I have been reading every day, but had not posted a thank you, for fear of being a post killer.


Any additional thoughts are welcome.


Al

leo g_64

jeff

i never had it put that way to me before. i was always under the impression that the stages were there for power savings, but your point makes total sense.

thanx
leo g

Bob_24

Electric boiler

Leo, we have an electric boiler that modulates based on built-in aquastat, supply water sensor and outdoor sensor /reset control. You'll really like it! In stock 6 - 23 kW. I'll be glad to send you info. Thanks!

mph

Modulating electric boiler

This sounds interesting. What brand is this?

Jeff

Bob_24

electric radiant

Thermolec is the Mfg. Link is available on manufacturers tab on this site. New updates are available, 12kW, etc. Let me know what you think.