All the info for an AGP heater. Natural Gas


Silver Supporter
Apr 21, 2015
Waterford, MI
We are considering a heater for out AGP. I want to plan it and price it out to see if its in a budget we can afford.

Stats on the pool are in my signature.We are in Michigan. The has meter is currently 175 cubic ft. per hour. Nothing in my home is gas except the furnace and the home is small. The distance from the meter to the pool is 140'

I understand many people say go with a 400 BTU heater (Looking on Craiglist all the used stuff only seems to be only 150 BTU). I also understand I will most likely need to call my gas company and get a larger meter.

My questions are ...
1. What size heater should I go with?
2. What size underground gas line do I run?
3. What size gas meter do I need? (
4. What else am I forgetting and do I need to know.



Silver Supporter
Apr 21, 2015
Waterford, MI
I found this chart.

Looks like at 150' I get, 324 BTU with 1 1/4" pipe
486 BTU with 1 1/2" pipe.

I found 1 1/4" pipe very easily. 1 1/2" seems to be much harder to find.

Cost is about $150 for the 1 1/4" pipe and another $250 for a couple risers. Misc fittings is probably another $50 in fittings. Reamer tool, probably another $50.

Sounds like $500 in material, plus the heater.


TFP Expert
Apr 29, 2016
Quaker Hill, CT
You probably don't need a 400k if a 1.25 inch pipe gets you over 300k that size heater is plenty for you pool.

I would suggest contacting a gas company they will be able to run flexible stainless pipe for you. They will also know all the local codes and permits required​. I'm all for DIY but you need to get it right the first time with gas lines.


TFP Expert
LifeTime Supporter
Apr 27, 2012
Grand Rapids, MI
Trick, I am in Michigan and am running a 24,000 gal pool on a 266 BTU Raypak, which will get me a little over a degree an hour.

I chose this size to avoid a meter upgrade and need to upsize my long run which also goes through my large, attached office that I didn't want to disrupt.

While its important not to under-feed a gas boiler, I've not had any trouble at all even running simultaneous with the house boiler and various NG appliances (I operate in he winter with an air-inflated dome, which is how I know this ;))

I'm thinking that if a 266 btu handles my pool IN WINTER, you'd be all set, and likely get more like 2+ degrees an hour or more, with a 266 ;)

In my pool, with efficiency in the Calc, I use about 2 CCF an hour when heating, which at our rate with all taxes and surcharges in, is about $1.54. Remember that a 400k btu unit will use twice that an hour. While sometimes it can be more efficient to heat fast, frequent cycles of dramatic fast heating can also end up being more expensive that a "dedicated heat retention plan" with scheduled, incremental warm ups. Its worth experimenting to see what works in your situation.

Before getting the dome, I ran 24/7 to 88 degrees May through mid-Oct, uncovered but using Cover Free to reduce evaporation. I did discover that in my case, wanting warm morning water for a swim, Thermostatting cost about the same as run-ups, making Thermostatting preferable because the pool was always the temp I wanted.

Since getting the winter dome this year and being highly motivated to keep my energy costs within a comfortable realm, I'm actually keeping 95 degree water 24/7 for less than my previous May bill most months ;) (January excepted.)

So make sure you have a good solar cover for our dramatically cooler nights, and or use an evaporate barrier like Cover Free to keep you NG bill down ;)


LifeTime Supporter
Jun 11, 2009
Exton, PA
You forgot about where to place the heater. I'm having one installed and the town has no code. They said refer to the manufacture's manual.

From Raypak: For windows and doors, 4 feet seems like the magic number. Air intake for the home is 10 feet.

• For U.S. installations, the point from where the flue
products exit the heater must be a minimum of 4 ft
(1.2m) below, 4 ft (1.2m) horizontally from, or 1 ft
(0.3m) above any door, window or gravity inlet into
any building. The top surface of the heater shall be at
least 3 ft (0.9m) above any forced air inlet, or intake
ducts located within 10 ft (3m) horizontally. See