which is cheaper, electric or oil boilers????

Uni R_2

Thermolec seems to make a nice boiler as does Laing...

cold in alaska

i built a house with radiant floor heat and am researching the best boiler for it. i have been told that the new electric boilers are great but no one will tell me how they compare to the electric ones in cost. does anyone know??

ALH_4

Cost

Oil is *generally* less expensive to operate, and electric is less expensive to install.

Oil:
($ per gallon)*7.14 / efficiency = dollars per million btu

Electric:
(cents per kWh)*2.93 = dollars per million btu

At least that give you a relative cost for oil versus electric heat.

Uni R_2

Here's the math...

#1 Take your fuel's BTU and divide it by the price.

If electricity is $0.12/kWh then 3,413/0.12 = 28442 BTUs/$

If oil is $3.00/gallon then 139,000/3 = 46333 BTUs/$

#2 Next apply seasonal efficiency rates to those numbers, electricity should be 100%, oil might be 70% - it's highly debatable.

46333 x 70% = 32433 so... 28442 vs 32433 (bigger is better)

#3 Now the tough part... with the oil, you'll need to factor in a servicing premium and also if your insurance company is like mine, you'll have to replace your oil tank every 10 years.

So you have to figure out your annual number of BTUs required to heat your house and how much that will cost and then add on a fixed estimate to cover the servicing difference and perhaps $120/yr to amortize a $1200 tank replacement every 10 years.

You'll need to use you own numbers but that's the math. Don't forget to buff the crystal ball because you really should be using expected fuel prices, not current prices. Commodity futures may be a useful resource. When calculating the electric rates, you have to strip out the fixed monthly portion to get the true marginal rate.


*edited*
You may also want to check with your insurance company and see if there is any kind of premium you'd have to pay for having the oil tank (and check if they have a set # of years replacement requirement when you're talking to them) and if so factor that into the annual costs.

cold in alaska

thank you for your help. i am still looking at all of the information.
i was wondering where the numbers came for the first calculation in the first response...i wasn't paying attention to who sent it. the 7 something and 2 soemthing...where did you get those and what do they mean? if i use my numbers of $0.13/Kwt and $2.50/Gal it comes up with electric being cheaper....is that right? i'm sorry, i need a lot of help!!!
thanks again

ALH_4

Units

You have to use cents in the calc for electricity instead of dollars.

Electric:
13*2.93=$38.09 /MMBH

Oil:
2.50*7.14/.84=$21.25 /MMBH

So oil costs 56% as much as electricity based simply on fuel cost and oil boiler efficiency.

The 7.14 and 2.93 account for unit conversion factors and btu content of oil.

Paul Rohrs_4

Siggy's HDS Software

Here are a couple PDF's with siggy's software

Regards,

PR

stephen_4

If you have very low cost electric and want to do hydronics what is the best electric boiler.

Unknown

I've replaced a clients oil boiler with an electric boiler. We've done the math by calling the electric & oil companies & getting their costs. We concluded that the electric boiler would be cheaper to run. Two heat seasons later and still is. Some electric boilers have outdoor reset to them. This will give more savings. Later on down the road if you wanted to go green & make it solar you can do that.

Plus with the electric boiler you don't have to worry about running out of fuel, or the expense to clean it every 6 months or a year.

Ken_40

Dear Cold in Alaska...

To determine the cost of any given fuel, be it electric, oil, natural gas, LP (liquid propane), coal or wood - you need to find a common factor so you can do the math and make a comparison!

The problem is, gas is sold by the "therm," (and-or cubic foot) oil by the gallon, LP by the gallon, wood by the chord, coal by the ton, electricity by the KW (kilowatt).

In north America, we tend to use BTU's (British Thermal Units) as the comparitive value for all commonly used, energy producing, fuels.

In order to campare any one fuel against another, we need to know how many BTU's (heat) each fuel is capable of producing.

By doing a Google on "energy conversion" or "BTU conversion tables" you may find the easiest way to review the data.

Since all energy ratings must be based on how long the heat is available, we typically use "hours" as the basis, rather than minutes or days. Unless stipulated as different, assume one hour is the time-frame the "BTU's" are produced.

Once you convert each fuel to a basic BTU "content," you can simply manipulate the BTU content back to the form the fuel is sold in; KW, BTU, Gallons, etc. - and see the actual cost per BTU for any fuel.

If you live near a hydro-electric plant, electric can be very cheap. If however you do NOT live near a hydro-generator, electric is extremely expensive, compared to its two leading competitors; oil, and NG (natural gas) sometimes, even LP - again, depending on what region of AK you reside.

One gallon of # 2 fuel oil has 140,000 BTU's of energy.
One Kilowatt has 3,412 BTU's of energy
One cubic foot of natural gas has 1,000 BTU's of energy
One therm has 100,000 BTU's of energy

I'm too lazy to do the rest of the fuels for you. Do the Google I suggested for the rest.

This is where you start. Next, the "efficiency" of each fuel is neded. Electricity has no chimney losses, so 100% of electric heat is standard. Boilers (or furnaces) however DO have efficiency issues. Most furnaces and boilers sold today will waste little from a chimney loss. A poor boiler/furnace would still get at least 80% for the home, 20% "losses" thru the chimney/vent. Many are in the negligible area; e.g., 95% for the home, 5% chimney/vent losses.

You must apply the efficiency "factor" to the fuel choice.

Sounds like a lot of work? Don't ask a fuel oil company to do it for you. Guess shat he'll tell you is "best." Likewise, stay clear of the LP company. Guess what they'll swear by?... Don't go to a tree guy. He'll have only wood stoves in mind...

You do the math, select a general solution, then call a few contractors that specialize in the form of heating fuel you selected, and you should get the answers you need.

BTW, a great resource is at the top left of this web-page; "Find a Professional" is the tab title. Plug in your zip and voila - a few names may pop up. The company's listed in that database tend to be head and shoulders above the Yellow Page contractors in you phone book.

Let us know how you make out!

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Ken_40

and...

If there's a power failure, you have no heat anyhow. Other than wood or coal stoves and NG millivolt generated gravity systems, you have no heat in any case!

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Uni R_2

\"One Kilowatt has 293 BTU's of energy\"

Ken, you may want to edit that...

ALH_4

Plan ahead

Some areas do have electric rates that beat any other fuel. In those areas, I would install a hydronic system with the possibility of installing a fuel-burning heat source if the price of electricity increases.

The Laing EPR heaters are very nice for smaller areas (15kW is the largest model). They take up very little space and have quite a bit of control function built in. If the system is designed for it, the integral pump in the Laing heater can be connected directly to the manifold.

Ken_40

You're both right...

1 KW DOES equal 3,412 BTU's

I'll correct the post. Thanks.

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Ken_40

HERE'S THE TABLE OF ALL TABLES !!!

http://www.ag.ndsu.edu/pubs/ageng/structu/ae1015a.pdf

Untainted by source bias as well. Looks like a colegiate study.

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Uni R_2

Or better yet...

Plug in your own numbers.

Uni R_2

Here, fill in the boxes...

The toughest two boxes to fill are the estimated annual efficiency for an oil boiler and the annual net BTUs required. I personally don't think that even the best oil fired conventional boilers can average over 70% during the course of the entire heating season, but I'm just an interested civilian. Sure they're 85-90% when they've just had a new nozzle put in and they are up to temp but in the shoulder seasons that efficiency must surely suffer.

The other tough number to know is how many net BTUs it takes to heat your house. I have a crude calculator in there that will take your annual heating degree days (you should be able to find that online) and your square feet of livable space and allow you to apply a factor. Tough part is that factor is still very crude and not nearly granular enough. For example, using 4 instead of 3 will increase your BTU requirements by a third... but it's still better than a WAG.

Don't forget the non-pure energy related costs become more important as you tighten the envelope because the annual difference in fuel costs decreases.

I'm in no way shape or form advocating a preference to either fuel, just that you really should try and compare ALL the related costs.

Good luck...

RonWHC

There is one

oil boiler out there that is over 85% for year round usage. Don't rep it. Don't sell it. Don't like the yellow color. But, I saw the numbers. From an impeccably independent source. Only a few points less than the published AFUE. Not that AFUE is a bragging point.

Why UniR, can't we add meter & system charges into our electric & gas usage numbers? W/ oil, the tanks belong to us. When they're paid for, they're paid for. No monthly charge for the privilege(?) of having someone else's meter record usage, or pipes/wires deliver the product. If that charge is on the bill, just like "rights of way fee, balancing fee, peak charge, or environmental surcharge" - it is an integral cost of the fuel. Bottom line is bottom line.

Uni R_2

Hrmmm...

Ron, what exactly was the study, who did it and where can we find the results? Frankly, I'd like to see a chimney that I couldn't use to warm my hands in the middle of the winter even with the boiler off for hours. After seeing just how much modulating condensing boilers can save, I'm pretty convinced that there is no possible way that they are only 5% to 10% more efficient that a good conventional oil fired boiler, and that's why I have a tough time using a higher number, but hey!... the user can put any number in that box that they want to. It's a model, he can plug in whatever numbers he feels is appropriate.

I'm not sure why you'd add the meter charges onto the electric. It's a flat fee and each month it is already owed, even before you even flick on the TV or a lightswitch. Using more OR less electricity doesn't change that meter charge, and that's why you leave it out of the equation. You have to separate the fixed monthly fees and forget them and just focus on the variable per KWH charge. Many here have a tough time with that and want to divide the total bill by the KWHs, but that's not going to give you the right numbers.

For example, let's say electricity is $10 for the meter/monthly fee and the variable portion (generation, transmission, etc) is $0.25 per KWH.

If we use zero electricity, the cost will be $10 - how much is that divided by 0?

If you use 200 KWHs the bill is $50 + $10 = $60. Suppose, with an electric boiler, the KWHs will triple during a certain month. If you triple the total of $60, you get $180 but in reality, it will be 3 x $50 + $10 = $160. If you want to overstate savings or costs, then by all means factor in the fixed charged into the per KWH charges, but if you want accuracy leave them out.

I completely agree that we own the oil tank, however, my insurance company requires that I replace it every 10 years, and many other peoples' insurers have similar provisions. If that's the case for this fellow, then that cost provision should be factored in at the interval specified by the insurance company, otherwise it might be 15 years unless he gets a high end tank like a Roth or the similar foreign tank in tank that Granby sells.

Ken_40

The FCX is 93% AFUE and was my choice...

The requirement to replace tanks at 10-year intervals is enforced where? Is this for in-grounds? How about 275's in dry basements?

Plastic tanks, stainless ones, double walled one's make that notion even more absurd.

A source for the 10-year change out code would be helpful - if it exists.

Not that I doubt you for a second (;-o)

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Uni R_2

Ken

TSSA is the code body that covers Ontario. There is absolutely no requirement to change your tank regardless of age unless it is leaking.

That said, most insurance companies here, including mine, have policies regarding mandatory replacement for indoor tanks. For mine it is 10 years and they don't care if the tank is made with 2" solid stainless steel plate. Insurance companies are creatures of fear and right now they seem to fear having to remove soil under houses much more than natural gas leaks blowing up and taking the house down on either side.

Anyway, like I've already said a few times, the guy can put whatever number he wants in the boxes but he might want to touch base with his insurance company to find out what their policy says about tanks, if anything.

----- ----- -----

With your super-insulated home and FCX, do you have any idea of you BTUs/HDD/SF? It would be interesting to know for comparison.

Ken_40

Assuming...

by BTU's/HDD/SF I suspect you mean BTU's per Heating design day per square foot?

If so, the data would be: 32,045 BTU's load on DD of -30F with 2,430 S.F.of total interior heated space (we also heat the garage and basement - not considered "living space" - but included in the load and S.F.) Actual true living space (the entire house interior less the basement and garage) is 1,810 S.F.

Was that the info asked?

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Uni R_2

Trying to see things on a level playing field...

Total gallons of oil burned this past winter heating season (try and factor out the portion used to produce domestic) x 139,000 gives you the BTUs.

The HDD is the cumulative HDD data from the nearest respresentative weather office covering this past heating season. Your oil company probably has this already... I go to wunderground.com but I was tracking it daily.

The square footage is the interior heated space. I'd include the basement. Not sure about the garage, but if it's kept the same temp, include it, otherwise factor for it how best you see fit.

You should have an extremely low number based on your construction and heating design.