# My Winter Coal Burning Formula for 2014 (Blaschak)

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

kstills wrote:
That calc for #2 doesn't seem to work out...

Well, lets see for both of them, using an example of a median temperature of 15 degrees F. for the day:

For electricity at 100% efficiency:
3.45 x (65-15) = 172.5 KWH
172,5 KWH x 3,412 BTU's/KWH = 588,570 BTU's (which equals 24,524 BTU's per hour for 24 hours)

For oil at 80% efficiency:
0.11 x (65-15) = 5.5 gallons
5.5 gallons x 138,600 BTU's/gal. x 0.80 = 609,840 BTU's (which equals 25,410 BTU's per hour for 24 hours)

OK, to make things a bit more even lets call it:
Gallons of #2 Heating Oil per day = 0.10616 x HDD's

And if (for example) the whole month of January averaged a very realistic (for this area) 20 degrees F:
31 x (65-20) x 0.10616 = 148 gallons of # 2 heating oil required for the month (at 80% efficiency)

But remember, my chosen factors of 3.45 KWH (electricity) and 0.10616 Gal. (oil) and 1.55 Lbs, (coal) are for my home only. Your home will likely be different. Also remember that there are a lot of oil boilers and furnaces out there that are older and may only be operating in the 60% to 70% efficiency range.
lsayre

Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

@ lsayre: just out of curiosity, how did you arrive at 4 pounds per day for DHW during the heating season? I saw in your post that you were burning 16 pounds over the summer to maintain fire and DHW? I'm trying to come up with my own formula. I'm averaging about 2 pounds per DD inclusive of DHW. Not completely linear consumption it seems. Will have to fine tune the formula once it gets steadily cold.
Carbon12

Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

As for just about all of my comparisons I converted it from a starting point of electricity being used for DHW, using available figures for how many KWH's of electricity two people would typically use monthly on average. The convienience of using electricity as a starting point is that you can pretty reliably figure it at 100% efficiency, and that takes a bunch of the efficiency guesswork out of the equation vs. starting from any other base (fuel), and leaves most of the guesswork strictly on the coal side of it. My home was all electric for a number of years also.

If a family of 2 adults (meaning here the wife and myself) typically uses about 300 KWH per month for electrically heated DHW, that equates to about 10 KWH per day.

10 KWH = 34,120 BTU's @ 100% efficiency.

I assume about 63% efficiency for coal, so 34,120 BTU's of required output for "DHW only" use divided by 0.63 = 54,158 BTU's of required coal input.

54,158 BTU's of input as coal required for our daily DHW divided by 13,200 BTU's per pound of anthracite = 4.1 pounds.

I round it to 4 pounds per day for convenience. That seems to keep me at about 1.43 lbs. per HDD (revised downward from 1.55 lbs. per HDD) for "home heating only" and it linearizes the coal usage for home heating vs. HDD's quite well (for November through March at least, and admittedly not as well for any other months).

In the end it's really just an educated guesstimate. It's probably not all that far off though. If you have more people at home you will need more coal (or electricity, etc...) to account for DHW usage. The available figures for an average American family of 2 adults and 2.2 children generally range in the ballpark of 450-500 KWH per month for "family sized" electric hot water tank supplied DHW demand. That would be closer to 6 or 7 lbs. of coal used daily for DHW.
lsayre

Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

Here's another way to look at DHW. This website says the average person uses about 20 to 30 gallons of hot water per day. Average = 25 gallons.

http://www.solar-estimate.org/showfaq.php?id=68

25 gal. x 8.34 lbs./gal x 70 degrees of temp rise = 14,600 BTU's per person per day for DHW on average.

For two people this would be 29,200 BTU's per day.

29,200 divided by 0.63 = 46,350 BTU's

46,350 BTU's divided by 13,200 BTU's per pound of coal = 3.5 lbs. of coal per day for two people, which is a bit less than the 4 lbs. that I'm assuming, but it's in the ballpark.
lsayre

Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

Thanks! There are three of us here and one is a 9 year old girl going on 19. Lots of long showers and laundry. I'm SURE my DHW needs are much higher than yours
Carbon12

Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

Carbon12 wrote:Thanks! There are three of us here and one is a 9 year old girl going on 19. Lots of long showers and laundry. I'm SURE my DHW needs are much higher than yours

2x at least. Kids dirty a lot of laundry and are water hogs in general.
Rob R.

Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Lehigh Rice
Other Heating: Dad's 1953 EFM Highboy

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

Carbon12 wrote:Thanks! There are three of us here and one is a 9 year old girl going on 19. Lots of long showers and laundry. I'm SURE my DHW needs are much higher than yours

You gotta condition them to be conservative otherwise they drain the tank.. I stand on the other side of the bathroom door while my 11 year old takes a shower, "come on Daisy, rinse off - shut the water off, yer running Christmas money down the drain"
Lightning

Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

A momentary closure of the ball valve that supplies the DHW from the water heater also does the trick
Carbon12

Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

Carbon12 wrote:A momentary closure of the ball valve that supplies the DHW from the water heater also does the trick

Lightning

Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

Current formula: 2.5 pounds/Degree Day. Inclusive of DHW. I was hoping for better than that. A recent realization actually makes me happy with those numbers. My ex and I got back together and it made sense for me to move in with her and her daughter in their house. I was looking around pondering the coal consumption and had a DUH! moment. The 2600 or so square foot house (not counting the partially finished basement) is almost entirely floor to ceiling picture windows and patio doors!!! Every room, literally, has at least one whole wall of floor to ceiling glass,....and several 4x4 skylights! I'm heating a freakin' green house! I pay the heating bills so I am soooooo glad I installed the coal boiler! No wonder her fuel oil bill was over \$4000.00 a year on top of the electricity the heat pump used! She kept the house at 66 degrees. I'll have none of that shivering bat guano! 72 degrees and all is well and warm contemplating sub floor radiant for the great room. Two of four walls completely glass with 2 sliding patio doors to boot and a cathedral ceiling. We spend most of our time in that room and having toasty warm floors might be nice. Not sure it would save any coal, however. Actually, the fireplace in the great room is begging for a small hand fired coal stove or insert. I do miss my hand fed!
Carbon12

Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

So what does it cost to heat the dhw? If you are using 16 lbs a day that is about \$2.50 a day and over \$70 a month and over \$900 a year, isn't that a lot of money for DHW?
I don't use coal for DHW, I use gas year round and spend around \$400 year for dhw... I have a high sierra shower head in all 4 showers, and we have a 15 minute shower rule {me and my sons do anyway, no one times my wife}. The water heater is set at 115* so no mixing needed just turn the shower on full hot and the water comes out hot 113-115{I have recirc so there isn't much loss from the water heater to the shower head}.

I have been trying to figure out my usage for a while, its not as easy as it looks, I fill my hopper and empty my ash bin about every 5 days which is 6 bags {about 250lbs}, with one burner lit, but when the temps start to get single digits at night I light the other burner and have to fill and empty every 3 days, when I compare it to the degree day readings I can't get anything to make sense, it may not help that my kids will leave doors open and bathroom fans on all night...
imcloud1

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

Electric bill dropped over \$100.00 since I started heating the water with the boiler rather than the electric water heater a month ago compared to previous month. No A/C or heat pump in either October or November. I doubt it takes me a half ton of coal ( money wise) to do DHW in heating season. Since this is my first season with the stoker boiler, I have no idea how much coal it will take to heat DHW and hold fire over the summer. Believe me, I'll be doing the math to see if the coal or electric is cheaper. Of course, the water muddies when not shutting the boiler off during the summer to prolong boiler life.
Carbon12

Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

Burning coal through the summer isn't for everyone. Depending on your cost for various fuels and how much hot water you use, it may or may not make sense. I have a family of 4 that uses plenty of hot water, and my options for producing hot water are the EFM coal boiler, or an oil boiler. The oil boiler averages one gallon of fuel per day...\$3.50. The EFM averaged 15 lbs per day towards the end of last summer...\$1.80 per day based on my recent coal cost. There was a thread a while back that discussed this: Burning All Year vs Electric DHW and Dehumidifier
Rob R.

Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Lehigh Rice
Other Heating: Dad's 1953 EFM Highboy

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

Carbon12 wrote: The 2600 or so square foot house (not counting the partially finished basement) is almost entirely floor to ceiling picture windows and patio doors!!! Every room, literally, has at least one whole wall of floor to ceiling glass,....and several 4x4 skylights!

...great room. Two of four walls completely glass with 2 sliding patio doors to boot and a cathedral ceiling.

No wonder it burns some coal.
Rob R.

Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Lehigh Rice
Other Heating: Dad's 1953 EFM Highboy

### Re: My Winter Coal Burning Formula for 2014 (Blaschak)

During the months when we use coal exclusively to provide for the homes DHW it costs us about \$1.90 per day for coal heated DHW vs. \$1.35 per day for electricity heated DHW. This situation lasts for about ~5 months.

But during the home heating months it is closer to only about \$0.48 per day for coal heated DHW and \$1.35 per day for electricity heated DHW. This situation lasts for about 7 months.

\$1.90/day x 152 days = \$289 for DHW
\$0.48/day x 213 days = \$102 for DHW
Total annual coal supplied DHW cost ~= \$391

365 days x \$1.35/day ~= \$493 annually for DHW from our electric hot water tank.
Last edited by lsayre on Wed. Dec. 11, 2013 10:18 pm, edited 1 time in total.
lsayre

Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Blaschak Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)