Natural Gas Heating Time & Cost Calculator Spreadsheet

BoDarville

TFP Expert
LifeTime Supporter
Jun 5, 2012
3,844
DFW, Texas
There have been several recent posts inquiring how long it would take or how much it would cost to heat a pool / spa using a natural gas heater. In response, I have taken on the challenge of putting together this spreadsheet to help answer those questions. It’s now ready to be test driven.

The spreadsheet has two sections:
  • 1. A Scratch Pad where you can estimate the hours needed to run the heater to achieve a desired temperature rise for a given water volume. There is a Multiplier Factor to account for variabilities in heating water that is subject to the elements. This is explained further in the spreadsheet.
    2. A Cost Estimator where you can select the billing unit from a drop-down list, cost per billing unit, heater BTU, and number of hours the heater is run. For the number of hours, you can use either the hours calculated in the Scratch Pad or enter your own figure. The spreadsheet calculates cost by taking the cost per billing unit and dividing it by the number of BTUs in that billing unit to arrive at a cost per BTU. It then takes the cost per BTU and multiplies that by the Gross BTU output of the heater to get the cost per hour to run the heater. The cost per hour is then multiplied by the number of hours the heater is run to arrive at the Total cost to run the heater for X hours.

A couple of other notes:
  • 1. Spreadsheet was created using Excel 2010 & 2013 (*.xlsx format). I was unable to upload an *.xlsx file format. So, I saved it to the Excel 97-2003 format (*.xls). As a result, it's possible that some of the fonts/colors may not display properly.
    2. Spreadsheet is set up to use with Natural Gas heaters only. It estimates the variable usage-based cost that appears on your bill. Fixed costs that appear on your bill are not factored into cost calculations since, by definition, a fixed cost is static and would appear on your bill as the same amount each month regardless of consumption.

Post to this thread if you have any suggestions or comments on this spreadsheet.
 

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BoDarville

TFP Expert
LifeTime Supporter
Jun 5, 2012
3,844
DFW, Texas
supercanadian: You're welcome, and thanks for the kind words. :)

caycarem: I do not have any experience with solar heaters for pool use. However several members on the forum do. Here are some posts you may want to look at: "solar+heating". From this list, you might want to start off looking at this post as it seems particularly germane to your interest : Data for comparing solar pool heating performance
 

jimbad83

New member
May 29, 2013
2
This is an awesome tool. I am thankful for your effort. I searched and searched and finally found an awesome website/forum with great resources. I am sure I will have tonnes of questions about my new pool and hottub. I'll let you know how accurate it is...My 400k BTU heater needs to raise the temp 23 degrees.
 

kjm11379

Well-known member
Apr 7, 2013
60
NJ
Wow, what a great tool, thanks so much for the effort. Now if only we had the same tool for a heat pump based on kWh...! :lol:
 

ChiknNutz

LifeTime Supporter
Jul 22, 2010
154
Advance, NC
By way of comparison, I just used this to figure out how much to raise my 36k ga. pool by just 5 degrees using Propane (don't have NG available to us here, out in the country). Assuming a 400k BTU heater, would need to run for 7 hours. Cost would *only* be about $65 per run!!! Propane cost uses was $2.28/Therm. Looks like I won't be in the market for a heater any time soon, even though the pool used to have one.
 

Patrick_B

TFP Expert
LifeTime Supporter
Jun 7, 2011
15,004
Midland TX
Finally looked this over, and this is really nice Bo. Thanks for putting it together and sharing it with us. Seems a bit cheaper to run than I thought.