Help me understand my heating bill: Average cost per hour to run gas heating system?

geoffh

I have an old steam system with a new gas boiler.



Can someone give me a range or estimate of how much per hour is costs to run my heating system? I know it won't be exact without knowing the exact usage of my boiler per hour but even an estimate would help.



House is 1398 square feet. 8 radiators. (3 bedrooms, 1 bathroom, 1 kitchen, 1 dining, 2 living room)



Gas company billing is as follows:

CCF used x Thermal Factor (1.0328) = Therms used



Gas Delivery Charge (Made up of):

Minimum charge of $.33 per day

First 40 therms at $0.4496

Remaining therms at $0.5343

Distribution adjustment $0.1792 per therm



Gas Supply Charge (Made up of):

$0.67270 per therm



So for 100 Therms, the bill would be:

Gas Delivery: $77.96

$10 (minimum charge)

$17.98 (first 40)

$32.06 (next 60)

$17.92 (distribution charge)



Gas Supply: $67.27



Total - $145.23



So the real question is, how many hours = 1 therm? (or 1 CCF?)



Here's a photo of the boiler if this info helps at all:

<a href="http://imageshack.com/a/img547/6651/kgi2.jpg">http://imageshack.com/a/img547/6651/kgi2.jpg</a>

Gordy

Per hour

Would the boilers btu INPUT divided by 100000btus (btus in a therm)equals number of therms per hour.



So if your boiler is 200000 btus it costs 1.34 an hour to run. If a therm is .67 cents after tax title and license.

geoffh

100k

How do I know the BTU of my burner? Or is the number you referenced something you saw in the photo?

Zman

Clock

If you have the time, you can just clock your gas meter during different conditions.

Your usage is obviously going to vary greatly based on the weather.

Carl

geoffh

Nest

The reason I'm asking is because my Nest thermostat sends me a monthly email with the total number of hours my unit ran last month. By changing my schedule I can see pretty clearly the results in hours it saves or uses. I'm curious how much those hours equate to actual $

Zman

Nest

With the nest, you will know how long you have a call for heat. You will not know how long the boiler fired for.

With a steam boiler you could clock the meter during a typical heating hour and get a pretty good idea.

Just turn up the t-stat and log the meter every hour. I would do it a few times during different conditions to see how consistent it is. Make sure any other gas appliances are turned off.

Carl

geoffh

Nest

Would a call for heat hour be more than the actual amount of time it fires?

JeffM

it can be

A steam system can have the call for heat be longer than the burner run time, if the call is long enough that the burner cycles off on pressure. The more oversized your boiler is the more likely that is to happen.

Gordy

Back calculate

If you know how many therms you were billed for (use actual not estimated billing).

You could use that information to calculate how long the burner fired for, and compare it to the nest time.



Of course if you have other gas burning appliances this complicates things, and you would have to correlate the billing cycle period with you nest.



Like others have said though the nest is telling you how long the system is calling for heat not how long the burner is using gas.



If you have the time watch your boiler during a heat call see how it reacts. If it cycles on and off during a single call for heat then your nest information won't be very useful, and this will vary with outdoor temps.

nicholas bonham-carter

Cost of heating

Even more important than the cost per hour, would be the fuel useage/cost per degree day per square foot.

I think I recall an earlier post in which you showed some bad piping on your boiler which was blowing a lot of water up into the supplies, and hammering, and causing the boiler to cut out on low water (or was that someone else?).

When you have water hammer, it is the sound of wasted energy, and you can compare the useage now with sometime in the future, when you have got the system back to its original state of repair and see how much difference it made to economy of running.--NBC

Mark N

IN-5

Looking at your picture your boiler is a Burnham IN-5. The input to that boiler is 140,000btu's per hour. that equals 1.4 therms of gas per hour. So to make it simple if your paying $1.00 per therm it would cost $1.40 per hour to run your boiler. Since you have steam you should just set your thermostat to 1 temp for the whole winter and leave it alone.

Zman

Cost

Mark,

The boiler does not necessarily run during the entire t-stat heating call.

The input rating work,  but will vary based on how the boiler is fired.

One could determine how many minutes per hour the boiler fires during a typical heat call and go that way. Or you could read the meter and get the real number.

With steam, the cycles per hour should be fairly consistent.

Carl

Mark N

True

Very true it might not be on for the entire call for heat. But it is also true that for every hour the boiler is running it will use 1.4 therms of gas.