Forum / THE MAIN WALL / Fuel use question?

## Fuel use question? (14 Posts)

• ### Fuel use question?

Looking at the following numbers, just curious if there is something I should do to improve my system for next year. Triangle Tube 110 propane.  Radiant slab and baseboard mix and 50 gallon indirect HW.  Design temp -9, outdoor reset. Heat loss 90k.

From Feb 3rd to March 5th, 31 days I used 322 gallons to heat my 3,400sq/ft home.
1400 degree days
During that time, the boiler ran for both heat and hot water priority for 400 hrs(330 for heat, 70 for hw) or about 13hrs a day.
So as I was burning about 10 gallons a day, the boiler was running about 13 hrs a day.
so 10.3 gallons x 91,500= 942,450/31=/ 24= 30,401 btu/hr/3400sq/ft=8.9 btu/hr per sqft
Does this sound correct?
On the other hand the boiler was burning 10 gallons a day running for an average of 13hrs.  If it (87k for lp) ran full tilt at 95%, it would burn 82,650 btu/hr.  x 11hrs( just for Heat) = 909,150= 37,881btu/hr/ 3400sqft= 11.1 btu/hr/sqft.  T
So in the end, I heated my house this month on 8.9btu a square foot and if the boiler had run at 100% it would have heated my home at 11.1 btu a square foot.  So is it safe to say, the boiler did its job and modulated?
This post was edited by an admin on March 5, 2014 11:20 AM.
• ### The best number for overall system efficiency

is BTUs per square foot per degree-day.  I get 6.19 using your monthly figures.
• ### that sounds better

How did you get to that number?
• ### Just use the monthly numbers

322 gallons X 91,500 BTU per gallon / 1400 degree-days / 3,400 square feet
• ### Ouch

I keep coming up with 18.2 for mine.
Weil-McLain EG-45 connected to 392sqft of radiation via two 2" risers into a 3" drop header and 2" equalizer. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment

Steam system pictures updated 6/5/14.

If I remember right, this puts you in the 88% group-only 12% of homes have a better efficiency than you-
• ### 88%

If the OP is in the 88% group, what am I in? The leaky sieve group? :)
Weil-McLain EG-45 connected to 392sqft of radiation via two 2" risers into a 3" drop header and 2" equalizer. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment

Steam system pictures updated 6/5/14.
• ### 75.5%

of homes are more efficient than yours-but you are better than 9.8%-so you are in the bottom 24.5%-
• ### Mistake

Ah! apparently as others have told me in the past the HDD reported by the gas company may be way off.

Using a local weather station from weatherunderground I came up with a number of 12.45 for one month and 14.7 for another.

I feel a little better now.

I really like this thread, I've learned an easy way to compare changes and improvements to my home.
Weil-McLain EG-45 connected to 392sqft of radiation via two 2" risers into a 3" drop header and 2" equalizer. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment

Steam system pictures updated 6/5/14.
• ### That Puts You

at 50%-right in the middle-
• ### Degree days

I make sure to collect them from the closest (or most similar) PWS.  I go to www.degree-days.net, download daily data for the previous two (or more) months, then prune the data so it matches the meter reading or tank filling dates and sum those up.

Two things you need to consider:  One is base temp -- for newer, better insulated houses, 65ºF is not a good assumption.  The other is non-heating appliance use.  Add up the gas or oil use over 3-4 non-heating months and divide that by the number of days to get an average daily use number and subtract that (multiplied by the days in the billing period) from the usage during the heating season.
This post was edited by an admin on March 6, 2014 12:09 PM.
• ### Here's one benchmark article.

http://www.homeenergy.org/show/article/nav/consumerinformation/page/2/id/825

The census was in 1997 but it gives you an idea. I would suspect those percentages have changed for the better 16 years since then.
This post was edited by an admin on March 5, 2014 7:17 PM.
• ### I saw that when I was

doing some research with my useage.  10 gallons a day seems like a lot but when I have to heat 3400 sq/ft, it isn't that bad.
• ### I forgot to add that

the 10.3 gallons a day figure also includes cooking stove and dryer so I am not doing too shabby.
I still need to dial in the boiler though.  I am having a bout 20 ignitions a day and that includes a 30 minute burner delay.  I sort of wish I had all zones into one with constant circulation.
•