Pool Heater sizing

[mumgoa]

I have seen different calculators but wanted to get an opinion from the experts on pool heater sizing (BTUs)

Looking to replace the one I have (H200 Hayward) with another gas heater

16 X 32 inground gunite
Shallow - 4 feet
Deep - 10 ft
in Michigan (metro Detroit)

Thanks

 

[mas985]

Much like filters, bigger is usually always a better choice especially if you plan on heating "on demand". The larger the heater, the faster it will heat. No downside other than cost.

 

[mumgoa]

Much like filters, bigger is usually always a better choice especially if you plan on heating "on demand". The larger the heater, the faster it will heat. No downside other than cost.

Thanks. Any recommendation on what BTUs size I need to shop around for.

 

[mas985]

450 BTU or larger.

 

[jedigrover]

Natural Gas? Check your supply for sufficient flow (capacity) and pressure to be sure you can support a bigger one. I have a 400k BTU. Heats up the spa pretty quickly. I had to get my meter replaced to run medium pressure & put a regulator right at the heater.

 

[Mayorb]

BTU's are BTUs.
A smaller heater will burn less gas (per minute) for a longer period of time than a larger heater will.
The larger heater will burn more gas (per minute) for a shorter period of time than a smaller heater.
It's up to you how quickly you want the pool/spa at temp. Most people go with a 400k , as the price is only a few hundred dollars more than the smaller ones. And yes, make sure (licensed plumber) your gas meter can supply enough for the heater to run correctly.

 

[1poolman1]

Every time I have had a customer opt for a smaller heater they have regretted it because of the time it takes to heat the pool or spa. Every time. Some have even asked to trade their new heater in on a bigger one. There are no used heater lots for many reasons.
For pool heaters, size matters. The only time a smaller heater might make sense is on a body of water that is continually heated, like a commercial spa.