# Thread: Cost to use natural gas heater

1. ## Cost to use natural gas heater

I was curious what the cost is to use a natural gas heater. I've read pretty much every thread on here and still don't think I've calcuated it correctly.

First I can't really figure out how much gas costs in my area of London, Ontario Canada. My billing is equalized so I don't see a regular charge to go from when converting.

I do find...
but this link does not show the add on costs onto the rates like storage/delivery.
http://www.ontarioenergyboard.ca/OEB/Co ... tes#prices

I am not sure what my rate really, even a guestimate at this point to make it useful for all the on-line calculators I see and tried.

Pool is 16000 gallons
jandy 250,000 btu heater (82% efficient)

How much would it roughly cost to raise the temperature 10 degrees? Assuming I am heating it when the outside temp is higher than 80 degrees.

2. ## Re: Cost to use natural gas heater

Okay, I have taken up the challenge.

That being said, I am assuming 16000 is US gallons, not Imperial units.

I read the link you provided, and added up all the positives and skipped the negatives because you can't ever count on the price of anything going down. Which ended up with \$0.215358 / m3 of gas.

This link gave me the conversion from m3 of gas to BTU. It's 36303.2807

16,000 gallons of water raised 10 degrees will take 160,000 BTU in a perfect world. at 82% efficiency, 195122 BTU.

Now, if I didn't mess up somewhere crunching the numbers, if your pool was a sealed system, it would cost you \$1.15. But you will lose a lot of heat to surface evaporation and heating the pump, filter, and the pool shell itself, not to mention the ground around everything to some degree, so I'd double it. Figure \$2.30.

Maintaining it at that temperature depends on the ambient temperature, ground temperature, wind, etc. So I won't even attempt that.

EDIT: OOPS. I made a boo-boo. A BTU raises one pound of water one degree, not a gallon!

Multiply the cost by 7.5

3. ## Re: Cost to use natural gas heater

OK, Richard320 seems to be reading my mind in that this post had been out there for a couple of days and we both decided to take this one on at the same time Saw his post when I previewed mine. Since I was 2/3 the way down the road, I'll post with my \$0.02.

It depends on how you are billed. Looking at the links you provided, it appears that usage is billed in cubic meters. The BTU in one cubic meter is ~ 36,000 BTU. So to figure your cost of running the heater for X hours, you would...
• 1. Take the cost per cubic meter and divide that by the BTU's in a cubic meter which will give you the cost per BTU.
2. Take the BTU of your heater (250,000) and multiply by the cost per BTU calculated in step 1. This gives the cost per BTU/Hr.
3. Multiply the result in step 2 by the number of hours you would run the heater

As an example, using the cost per cubic meter that Richard provided of \$0.215358 and dividing that by 36,303.2807 (BTU's in a cubic meter) gives a cost per BTU of 5.93E-06 (suggest using a spreadsheet to input these figures...will make more sense). This is the ending result for step 1 above. For step 2, multiply the 5.93E-06 * 250,000 BTU of your heater. This results in \$1.48 per hour to run your heater.

Since your heater is 82% efficient, only 205,000 BTU goes toward heating your pool. Therefore, I would figure the temperature gain using 205,000 BTU, not 250,000. The remaining 45,000 BTU is vented to the atmosphere. But as far as the gas company is concerned, you are still burning 250,000 BTU's per hour.

As Richard adroitly stated, several factors determine how long it will take to heat your water to a target temperature. Every pool and situation is different and will take some experimenting on your part. For my pool & heater (400K BTU * 81% efficient), I get a 2°F rise per hour in an uncovered pool with an outdoor temperature in the 50° to 60°F range with average wind speeds of 10 MPH (less than that on windier days, a little more on calm days).

4. ## Re: Cost to use natural gas heater

Thank you both for your replies and time spent helping me figure out the costing. My only concern was the cost to heat up the pool, I was not sure if I was looking at \$20 bucks for 10 degrees or \$100!

I can stomach the 30-40 bucks it looks like it would cost me to get me a 10 degree increase. It is a long weekend here and suppose to heat up tomorrow and wanted to take my pool from the current temp of 64 (burrr) to something more pleasant so my family can swim....but not if it was going to cost me 200 bucks!

5. ## Re: Cost to use natural gas heater

Originally Posted by Richard320
Okay, I have taken up the challenge.

That being said, I am assuming 16000 is US gallons, not Imperial units.

I read the link you provided, and added up all the positives and skipped the negatives because you can't ever count on the price of anything going down. Which ended up with \$0.215358 / m3 of gas.

This link gave me the conversion from m3 of gas to BTU. It's 36303.2807

16,000 gallons of water raised 10 degrees will take 160,000 BTU in a perfect world. at 82% efficiency, 195122 BTU.

Now, if I didn't mess up somewhere crunching the numbers, if your pool was a sealed system, it would cost you \$1.15. But you will lose a lot of heat to surface evaporation and heating the pump, filter, and the pool shell itself, not to mention the ground around everything to some degree, so I'd double it. Figure \$2.30.

Maintaining it at that temperature depends on the ambient temperature, ground temperature, wind, etc. So I won't even attempt that.

EDIT: OOPS. I made a boo-boo. A BTU raises one pound of water one degree, not a gallon!

Multiply the cost by 7.5
What do you mean the cost by 7.5? do you mean the 2.30 by 7.5?

6. ## Re: Cost to use natural gas heater

Originally Posted by Richard320
Okay, I have taken up the challenge.

That being said, I am assuming 16000 is US gallons, not Imperial units.

I read the link you provided, and added up all the positives and skipped the negatives because you can't ever count on the price of anything going down. Which ended up with \$0.215358 / m3 of gas.

This link gave me the conversion from m3 of gas to BTU. It's 36303.2807

16,000 gallons of water raised 10 degrees will take 160,000 BTU in a perfect world. at 82% efficiency, 195122 BTU.

Now, if I didn't mess up somewhere crunching the numbers, if your pool was a sealed system, it would cost you \$1.15. But you will lose a lot of heat to surface evaporation and heating the pump, filter, and the pool shell itself, not to mention the ground around everything to some degree, so I'd double it. Figure \$2.30.

Maintaining it at that temperature depends on the ambient temperature, ground temperature, wind, etc. So I won't even attempt that.

EDIT: OOPS. I made a boo-boo. A BTU raises one pound of water one degree, not a gallon!

Multiply the cost by 7.5
What do you mean the cost by 7.5? do you mean the 2.30 by 7.5?
Yes

7. ## Re: Cost to use natural gas heater

Wow that changes the game then for me if I understand correctly I am looking at around 170 bucks to heat it up 10 degrees. yikes!

I might wait for summer weather now!

8. ## Re: Cost to use natural gas heater

Wow that changes the game then for me if I understand correctly I am looking at around 170 bucks to heat it up 10 degrees. yikes!

I might wait for summer weather now!
No....2.3 * 7.5 = 17.25

9. ## Re: Cost to use natural gas heater

Originally Posted by Richard320
Wow that changes the game then for me if I understand correctly I am looking at around 170 bucks to heat it up 10 degrees. yikes!

I might wait for summer weather now!
No....2.3 * 7.5 = 17.25

Oh my bad, so 17 bucks to heat it up 10 degrees? I can handle that!

I feel like I am taking and not giving here, can I donate to the site or something to help out for all the advice?

10. ## Re: Cost to use natural gas heater

I feel like I am taking and not giving here, can I donate to the site or something to help out for all the advice?
Well, that's what we are here for. But thanks for inquiring about making a donation to the site. TFP would benefit from that plus there's a few perks in it for you. Here's a link where you can learn more about donating to the site: http://www.troublefreepool.com/click...rter-t183.html

11. ## Re: Cost to use natural gas heater

"EDIT: OOPS. I made a boo-boo. A BTU raises one pound of water one degree, not a gallon!

Multiply the cost by 7.5"

Richard, did you mean to convert from gallons to pounds? If so, the conversion is 8.25 lbs/gallon - you may have been thinking conversion of cubic feet to gallons, multiplying times 7.48 gallons/cubic feet ?

But, that doesn't change the results too much, plus with all the other estimates, it's ballpark, anyway.

12. ## Re: Cost to use natural gas heater

Originally Posted by DWSPool
"EDIT: OOPS. I made a boo-boo. A BTU raises one pound of water one degree, not a gallon!

Multiply the cost by 7.5"

Richard, did you mean to convert from gallons to pounds? If so, the conversion is 8.25 lbs/gallon - you may have been thinking conversion of cubic feet to gallons, multiplying times 7.48 gallons/cubic feet ?

But, that doesn't change the results too much, plus with all the other estimates, it's ballpark, anyway.
Double Oops.

13. ## Re: Cost to use natural gas heater

Just wanted to update:

I heated up the pool for the weekend, no matter the cost it was well worth it! wow great weather, even better family time spent!

The starting temp was 62 that morning, by around 2pm it was 80, and the next day it got up to 83 even though i set the heater to 80! I covered the pool that night of course but we got great swimming in on Sunday and all day Monday. I took recordings at my gas meter before and after.

Sunday turned on my heater at 7am (water temp 62).
Meter: 52113
Sunday night at 5pm turned off heater(water temp was 81- Heater was set to 80):
Meter: 52174
Gas used: 63 Cubic Meters

Monday morning 8am (water temp 78):
Meter: 52175
Monday afternoon turned off at 3pm (water temp 83):
Meter: 52186
Gas used: 11 Cubic Meters

So if I understand how much I am paying per cubic meter of gas the cost was not that bad! Either way the weekend was fantastic and really felt like we hit an island resort. Family fun, priceless!

Thanks everyone for the insight and help!

14. ## Re: Cost to use natural gas heater

FYI, I just posted a spreadsheet to estimate natural gas heater runtime and cost for heating pool/spa water for a desired temperature rise here: Natural Gas Heating Time & Cost Calculator Spreadsheet. Feel free to give it a test-drive.

15. ## Re: Cost to use natural gas heater

Brilliant spreadsheet. That's is very handy!

Thanks!

16. ## Re: Cost to use natural gas heater

and dont forget to use ther solar cover at night to save more heat loss and use the sun's power during the day to help even more on savings.......turn the filter off during the day unless you are in it so the water stays still and heats up even more.....my pool water on the top six inches will reach over 90 degrees on a sunny day.....FREE HEAT...WOO HOOO

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