Looking at things rather simplistically, it takes the same number of BTUs to heat a volume of water from one temp to another. The difference in heaters will be the length of time it takes to heat the water. Again, theoretically, a 400kBTU heater will heat the water in half the time a 200kBTU would take to heat the water.

For a larger pool, I generally advocate using a 400k heater. When you want heat, it'll give you heat. If you heaat your water full time, or most of the time, then a lower BTU heater can maintain a temp fairly easily. It'll just run longer while doing so.

As to which brand, I prefer Raypak, as they are well built and easy to DIY install, maintain and repair. You'll find that installers in your area may be beholden to one brand or another, so that may sway your choice.I had issues with my old Pentair heater, the electronics in it just seemed too finicky and temperamental.

Pool pump? I truly believe a variable speed is the way to go. My old single-speed 1-1/2HP Pentair WhisperFlo would run 10-12 hours a day, using over 2000 watts as it ran.

A couple of years ago I replaced it with a Pentair variable speed pump. After a bit of trial and error, I run this pump at 1400rpm, which uses less than 200watts as it runs. Roughly 1/10th the electrical consumption of my old pump. When I put the cleaner in, I press the "quick Clean" button on the pump and the speed ramps up so the floor cleaner has enough flow to clean well. The pump paid for itself in just about one season. Beyond that it's been pure savings.

It's easy to program the pump for any schedule; run it at a certain rpm for filtration most of the time, with an occasional bump in speed for a floor cleaning cycle, for example.

How to find someone? Ask friends? Neighbors? You can find installers through manufacturer's websites, though not all seem to give complete referrals. You can call pool companies and see what they have to say. If there is a gas company in your area, you can call and ask if they install heaters.

Just one pool owner's opinion.

Good luck!

Good info, Thank you! I've been pretty satisfied with being able to flip the heater on high in the morning and have the water comfortable by afternoon so will probably look for about the same size.

Just how long does it take for a professional installer to put one in? Our pool company that opens/closes our pool quoted $2900 for a Raypak, nickel heat exchanger. My husband found one from Fl he could order for 1600 (maybe 1500) and free shipping). Pool guy admitted he included a markup on price. Is this customary?

Am looking for a pool heater- was already thinking about Raypak, but now I have no doubt- so that decision is made! Thanks MongoCT! And maybe I am looking for a variable speed pump too

I'm not sure on your location, but I have a solar pool heater. Very economical, and it heats all day long (as long as there is sun). You might even get a tax credit for it. I second the variable speed pump. My pool guy installed it this year, about $1500. Got a big rebate from my utility, and I literally save $500/year in electric cost over the old one. It's also a Pentair.

Ordered a Raypak at a savings of $1200 over quote from our pool guy (but we checked with him on make and model and he said it was a good deal). Installed it this week but waiting on them to send someone out to hook up the gas since the connections didn't line up. Will let you know how it all comes out :)

Had our old pool heater guy, on verge of retirement, look at the heater - he advised against a 399/ 4000 k BTU heater as it needs a larger gas line than what we currently have, and it needs a larger stack/ chimney diameter (10" viz 9" for current model) So he recommended the 366 K BTU Raypak - will order it this week sometime

First, to learn how to properly size a pool heater for your pool read this article: Pool Heater Reviews & Sizing

If you have a 260kBTU heater then you can surely replace it with something of similar size and you will notice that it operates more efficiently. While you could explore a 3200k BTU heater the problem is that 250k BTU heaters are the most common on the pool market. So much so that 200k BTU heaters are often the same price or even slightly more than the 250k models.

As for pool pumps you are absolutely right that a variable speed pump will save you on your electrical costs. Many areas are now requiring variable speed pumps by law on all new and renovated pools because they are that much of a efficiency improvement on pools. If you want to see which are the most popular VS pumps and how to choose the right one for your pool you can read this article: Variable speed pool pump reviews

Old thread! again!