Elec Boiler / My Elec Bill $$$

mark ransley

The utility co said you are 06.5 cents kwh, I never had a utility co give me taxes in their figure, .065 maybe and maybe .07 worth of taxes and fees. What does your bill say, I know of no area Electric is now cheaper than Ng, where are you.

Jim Gresko

Elec Boiler / Radiant Heat / My Elec Bill/Off Peat

Having installed an elec boiler to radinat heat approx 2800 sq ft of a well insulated log home I find my elec bill at $500+ monthly while i maintain a 65 degree temp among 3 zones.

Utility company and electrician say my "off peak" sensor is working while my heating contractor has his doubts about whether the off peak sensor was properly wired.

Can anyone advise this homeowner what to do next as $500 month in electric billing is outrageous. Thank you.

Andrew Hagen_2

Rates?

What are your electric rates?

Metro Man

t-stats

Are you setting back you t-stats? If so you will want to change to constant circ and maintain temp. If your trying to only heat in off peak times the cost to get home to temp may outweigh the off peak savings.

Most any radiant heating system operates better with a constant temp/circ. when occupied...... and yes what are your rates, what was heat loss with this well insulated home?

Metro Man

Jim Gresko

Andrew - Utility co. informs me the "regular" rate is 10.3 cents and "dual fuel" (which I'm on) is at 6.5 cents.

Unknown

what does "well insulated log home" mean, and where are you? and, what are your rates?

Jim Gresko

Metro Man - I keep the thermostats of all 3 zones at a "constant" 65 degrees...

Jim Gresko

Rob...the avg log circumfrence is 24" (big logs should retain heat) and around the home's foundation we attached 4x8 sheets of 2 inch pink insulation down approx 6 feet.

Jim Gresko

Rob - I'm in NW Wisconsin in the Town of Cable having built on the Namakagon River.

scrook_2

Several thoughts
1. Have your utility check their meter peak/off peak timing.
2. check your peak & off peak rates.
3. build hot water storage for heat to use during peak periods
4. convert to fossil fuel (even if propane), ground source heatpump, air heatpump, and/or solar as appropriate for your location/climate -- electricity is generally BRUTALLY expensive for heating as you're seeing.

Unknown

so 6.5 cents is about 221 BTUs per penny.

Jim Gresko

Scrook - after getting your msg i ck'd with the utility co and their claim is that all is working properly from their end...the rep didn't seem to understand anything about checking "timing" - perhaps i should run a propane line come spring and use propane for radiant floor heat going forward - i was lead to believe that "Off Peak" was the way to go over Propane...

Metro Man

heat loss

You really should have a heat loss done to home b4 you spend any more $$$. Log homes are different when crunching numbers than conventional stick. It's not as much a heat loss as it is the time heat takes to travel through log.

Also what is radiant distribution system.... tube in concrete, gyp, or ???, staple up, or ?? What centers is tubing?.... etc...

A poorly designed radiant heating system will suck btu's wether gas, solar, or electric.

Metro Man

Unknown

so 6.5 cents is about 525 BTUs per penny. propane is about 92kBTUs per gallon, so you can divide that out and get your BTUs per penny.. minus efficiency loss. usually 6.5 cent electricity isn't bad for heating though.

December and January had 1750 and 1976 degree days at the hayward airport this last winter.

If you used $500 in january, that's about 13,300 BTUs per degree day.

For subzero design temps like you've got, that's about what I would expect from a log home of about your size.

Andrew Hagen_2

Fuel Comparison

I guess it's just the way I learned it, but I prefer to make the comparison based on price per million btu.

6.5 cents per kWh is $19.04 per million btu

10.3 cents per kWh is $30.18 per million btu

$19.04 per million btu = $1.66 per gallon propane at 95% boiler efficiency.

So if your propane is over $1.66, which it probably is, you are better off at 6.5 cents per kWh.

It is likely that the cause of the particularly high heat bills is the heat loss. Even a well built log home is not very energy efficient compared to a stick-frame home.

scott markle_2

"A poorly designed radiant heating system will suck btu's wether gas, solar, or electric."

OK like:
- Poor slab insulation
- micro zoning that causes short cycle
-heating curves too high and bing bang t-stats
-Boiler over-sizing
-over pumping
-inadequate emitter
-some others I missing

Some of the above are probably fairly common in "good systems"

While system designs are important we are ultimately chasing a narrow band of what is possible in terms of efficiency. I believe this is worthwhile pursuit, especially when improvements can be realized by ideas as much as hardware.

However unless we are doing something that is obviously wrong, there are not that many percentage points between a good and great system.

It comes down to energy in and energy out, how we deliver the btus has an effect but it's not game changing. I can't see how a radiant system that has proven it's ability to deliver it's heat could be flawed in a way that would have much of an effect on an electric boiler. Remember the efficiency of electric resistance is not effected by operating temperature the way a combustion device is.

If you have an off peek rate I agree with the storage suggestion, might be nice to have a mix valve with constant circ. running off a storage tank anyway. How is your electric boiler currently plumbed and controlled, does it modulate?
How about some pictures?

Gordy

Big Logs

Are they hard wood or soft wood?

Lets assume soft wood, so that would put you at an r 21 roughly at the thickest point of the log. That would seem like a good r value.

I think that there comes a point where a log becomes a conducter more than an insulator, much different then a r 21 stick built assembly.

Then there is infiltration. How are the logs fitted. There is much more chance of infiltration in a log home wall assembly. Infiltration is a killer when it comes to heat loss.


Gordy

hot_rod

have a blower door test performed

energy efficient log homes is sometimes an oxymoron.

Only an infiltrometer can tell how much the structure actually leaks. It is possible that the building is driving that consumption. This test will define the "leakage" and show you where it it to address it.

It's not just the R-value of the log, but the leakage around connections, penetrations doors and windows. It takes care to keep them sealed up as the dry, shrink, and settle.

There are a few manufacturers building thermal storage just for off peak use, check into those. I've seen 4.5 per KW in Minnesota and consumers there take advantage of these off peak rates to wind up the flywheel.

But until you know the true, "as built" load, we are all guessing.

Many utilities offer blower door tests, if not look for a local HVAC company to perform one.

hr

tim smith

I was just going to say same thing HR, I would bet the infilt.

rate is quite high on that log home. The logs settle, chinking separates a bit, windows to logs move while settling. Just a thought but quite possible. Tim

Mark Eatherton

It R what it R...

I agree with HR. SHort of significantly changing the esthetics of the log home, the only heat loss factor you have control of is infiltration. Do a blower door test and see how bad you log home leaks, and plug those leaks.

As for "OFF peak" electrical rates and systems, as others have pointed out, the ONLY way for it to be economically viable is to have on site storage, charging that storage during off peak rates, then keeping all electric resistance heating elements off line during PEAK demand. One system that comes to mind is the Steffes Electrical Thermal Storage system. They do have one unit that we have installed that is specifically for hydronics.

http://www.steffes.com/offpeak/comfortplus/hyd_overview.aspx

The power companies sensors may be set up OK, but if the boiler is not being locked out during peak periods, you are purchasing electricity at the elevated rate during peak hours. That is the whole idea behind peak demand programs. When they are under peak demand, they DON'T want you drawing power, and if you do, there is a financial DISINCENTIVE to keep you from doing so.

If you already knew all of this, sorry for the reminiscing. If you didn't know, consider yourself educated :-)

ME

Mark Eatherton

R you kidding....

Gordy, I have asked every log home manufacturer that I have worked with what the net R value of their logs are, and not ONE of them has ever responded. They go of on this tangent about "It really not the R value that is important as it is the flywheel mass effect of having all of those massive logs within the space... "

BUNK!!

And infiltration is a moving target. It changes constantly with time. If you don't keep up on it, it can overwhelm the heating system and then you are dealing with the slipping clutch syndrome....

ME

Gordy

Generous

Yes I agree Mark its a whole different animal. I was giving a generous example of r.84 per inch for softwood.

I still think a "hole" log assembly is a completly different animal then a stick built. With variable log thickness, time of which creates new cracks, and crevaces for infiltration. Plus conduction more then thermal mass.

I say if you like log home look go with half log, and standard stick wall assembly.

It would be interesting to hobo a log with sensors at various depth in a log to see the battle between interior, and exterior temps. See where the mason dixon line is temperature wise with in a 24" log.


I once came across a person who was building a log home of a different tact. He was stacking 24" long logs using mortar in brick wall fashion. What do ya think infiltration is on something like that? after 3,5,10 years as logs dry out, and shrink.


I'm with ya Mark.


Gordy

steve_206

If the R value of the wood is .84/inch shouldn't the R value for the wall be .84*8 or about R7 since 8" is roughly the thickness of a 24 inch circumference log?

Gordy

Gordy

ooops

Your right my bad, I miss read thought I read Diameter. 24" dia logs not uncommon.


R 7 Woof thats bad.


Gordy

Unknown

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Mike C._4

Electric rates?

Does the 6.5 cents/kwh hour include the distribution charge? My bill is broken down into power generation and distribution which is a little higher. Amazing yopu can get electricity that cheap. I pay 18.5 cents total in Maine.

Mike C.

Rich Kontny_3

Jim

I was born and raised in Ashland and could recommend some resources. Omer Nelson Electric could probaly help you with meters etc to check usage. KBK Services in Ashland may have an infrared gun to check heat loss.

I do not remember if Cable has it's own electric utility or is Excel. If Excel you should be able to get some accurate answers from their customer service center in Ashland.

Sounds like you have a beautiful place. I am very familiar with Cable and the Nemakagon River, it is truly God's country!

You unique point to remember is the fact that the Bayfront Power Plant in Ashland is 2/3s powered by wood waste a very abundant and renewable resource in northern Wisconsin.

Jamie Hall

Besides the infiltration bit...

and seems to me the comments are right on...

Check with the utility for a possible quirk in billing: some 'off peak' billing systems will charge on peak rates if the power usage goes above a certain value at any time during the day -- for the whole day, or even for the whole billing cycle.

Even if that isn't the case -- but especially if it is -- do make darn sure that the elec. boiler and other resistance heating stuff (like a water heater?) is locked off during the on peak times.