I would say that's a fair price if that includes the cost of installation and setup, the bundle is about $500 retail. Certainly most people want it for the convenience factor, I just wanted to point out it wasn't required when adding a heater.
Natural Gas Pool heater Questions
- Thread starter Karenyn
- Start date
For you, and for anyone else who reads through this thread in the future, here is how heaters work as far as your decision goes. If you do not like math, stop reading this post.
A BTU is the amount of energy needed to increase 1 pound of water by 1 degree. To make this more usable, it takes 8.33 BTUs to increase 1 gallon 1 degree.
Let me give you an example that is super simple, and leaves out lots of factors I will bring in later after the example.
Your pool is 10,000 gallons, and is 80 degrees. How many BTUs do you need to increase the pool to 85 degrees?
The math answer is (# of gallon in pool) x (8.33 BTUs per/gallon) x (Desired end temp - Starting Temp)
10,000 x 8.33 x 5 = 416,500 BTUs.
So in theory, it would take a 400K BTU heater 1.04 hours to raise the pool temp 5 degrees. But that is in theory and does not include lots of factors. Now in practice things change, and here is just a list of how this might happen.
The big factor is your pool losing temperature to the air and the ground. For this, I can only give you an example. Right now my pool gets up to about 80 during the day, and is dropping down to 76 at night, while the air temp is going from about 80 down to 60 over the same period. How does this effect your heater? Well going back to the example, I have this as an estimate.
10,000 x 8.33 x (76-80) = - 333,200.
Lets just say that this is linear (which truthfully it is not for lots of reasons that arent important now) but you are losing 333,200/12=27,767 per hour. So now lets look at the math example in a more complicated way
What happens in 1 hour of the heater being on?
-Generate 400K BTUs
-80% efficiency means you need 500K BTUs to create that amount of output going to the pool.
-On your gas bill, 1 therm = 100K BTUs
-500K BTUs is 5 therms.
-A therm of natural gas will be around $1 on average, so it will cost $5 per hour to run your 400K pool heater for 1 hour at full power.
But then how will this effect your pool?
Going back to your 10K gallon pool, you need 8.33 BTUs per gallon per degree, so that means to raise your pool 1 degree, you need 83,300 BTUs
In our example, you generated 400K BTUs, so simple division says that you generate enough heat to raise your pool 4.8 degrees. Now in my example (and yours will vary here) you will also lose about 28,000 BTUs of heat in that same hour, so now the math looks like this
(400,000-28,000)/83300= 4.4 degrees in 1 hour and it would cost you about $5 to achieve that
I think this math is right, though Im sure someone will point out a typo and then I will edit accordingly.
Sorry for the math.
Thank you Yev, I did do that calculation on what it would take to raise my temp in 24 by 20 degrees, BUT you example explains even further and gives a few other details that I did not know. Thank you and I will have to keep your post to I can always remember how to calculate gas cost etc. I did buy the 400k unit. i just felt after the details i got here that would be the best option. I also think I will get the automation.
Nectarologist
Well-known member
- Apr 3, 2015
- 642
- Pool Size
- 21000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Hi Karenyn,
You need to be sure you have the properly sized supply line coming into the home from the street (or wherever the source) and you need to be sure that your meter can handle the demand your home will place on it. Your utility company should have a worksheet that basically calculates your gas demand based on what you'll be running (probably a grill, stove, and pool heater in the summer). Overall it may use the same amount of gas as a smaller heater over time but the amount of gas to feed a 400k heater is larger and a supply line of x inches for a 250k heat may not be large enough for a 400k heater. If the supply line can't feed the heater the required volume & flow of gas the heater won't operate. I'm not a plumber but when they explain it to you it will make sense. Hopefully they took this into consideration & I wrote this for nothing
Just wanted to mention now rather than find out that hard way.Gas lines capacity is charted via to cubic feet of gas, not BTUs. 1 cubic foot equals 1000 BTUs. For a 400K BTU heater, that consumes 400 cubic feet of gas per hour when running full capacity (which it will often). So basically there are published charts that show if your existing gas lines can deliver that volume of gas. TO figure this out, you need to map your whole house gas lines, and determien flow rate and demand throughout. I will only say this. a 400K BTU heater is a huge demand of natural gas.
To put it into perspective, a typical whole home gas furnace only uses 100K BTUs. A dryer 35K. A water heater 50K. a fireplace 75K. A range/oevn 100K. So your whole home gas system was deisnged for about 360K if all appliances are gas, which is less that what your 400K heater will use. So there is a chance that your current lines will be undersized, and if so, the cost to deal with this can be expensive. There are options, but plumbers arent cheap.
To put it into perspective, a typical whole home gas furnace only uses 100K BTUs. A dryer 35K. A water heater 50K. a fireplace 75K. A range/oevn 100K. So your whole home gas system was deisnged for about 360K if all appliances are gas, which is less that what your 400K heater will use. So there is a chance that your current lines will be undersized, and if so, the cost to deal with this can be expensive. There are options, but plumbers arent cheap.
Yes, I got a quote from a few plumbers and they told me that I would need a 3/4 line installed and the gas company would need to put a high capacity meter in. I was chatting it up on another forum about gas lines and they all convinced me that CSST is Crud and that I should go with black iron or copper. I don't think Copper is available in my area for gas lines. Anyway, They mentioned that CSST has a host of issues including being able to catch fire during a lightning storm. I read that somewhere else and it wasn't clear if the lightning needed to strike your house or what. Anyway once the heater is placed I will have the line installed.
Thank you for the information. All of the plumbers mentioned that i needed to have my meter changed to a high capacity meter and that they would have to install 3/4" piping.Hi Karenyn,
You need to be sure you have the properly sized supply line coming into the home from the street (or wherever the source) and you need to be sure that your meter can handle the demand your home will place on it. Your utility company should have a worksheet that basically calculates your gas demand based on what you'll be running (probably a grill, stove, and pool heater in the summer). Overall it may use the same amount of gas as a smaller heater over time but the amount of gas to feed a 400k heater is larger and a supply line of x inches for a 250k heat may not be large enough for a 400k heater. If the supply line can't feed the heater the required volume & flow of gas the heater won't operate. I'm not a plumber but when they explain it to you it will make sense. Hopefully they took this into consideration & I wrote this for nothing
Happy to hear you are on top of things. We were just worried that you could have a big cost that you were not prepared for.