I have a 27' above ground pool that is about 17,000 gallons. The wife found a used Hayward H100ID on Craigslist for $250 and it seems like a good price but it seems small for my pool. I live in Northwest IN about 30 minutes south of Chicago and we use a solar blanket and right now the temp of the water in the morning is in the low 70s and she would like to be in the mid to high 80s. I would like to do solar but I don't have a good spot except for the roof which is two stories up and I don't think the HOA would approve. What is the minim size heater that would be good for my size pool?

Thanks, Wade

There are a couple of things to understand about heaters. First they are fantastically expensive to use. Swimming pools need way more heat than even an entire large residential house uses in mid-winter. Many people think they are going to heat their pool but give up after the first month or two of utility bills. This is the huge advantage of going solar, minimal ongoing costs.

Second there are two ways to use a heater, which have very different requirements. Some people swim all the time and want the pool kept warm all the time. This can be done with a fairly small heater and a heat pump is often a good choice in this situation. Other people only heat the pool for the occasional weekend, and care mostly about getting the pool to go from cold to swimmable as quickly as possible. For that you need the largest heater you can possibly get (usually 400,000 BTU) and gas is really your only choice. Even with a huge heater it can take many hours, even more than a day in some cases, to bring the pool up to swimming temperature in the spring and fall.

I did some reading online it if the what I read was correct that it would take 14 hours to raise the pool temp 10 degrees with a 100k btu heater.

That is under ideal conditions with no heat loss of any kind. In reality it could easily be twice that long and in some weather conditions it would never go up 10 degrees because the pool is capable of losing more than 100,000 BTU per hour in some situations.

I have a 240,000 BTU heater and a slightly larger pool. During the day I can sometimes get 2 degrees an hour, though 1 degree an hour is more common. But at night in the early spring and late fall I often simply hold the current temperature despite the heater running constantly.

Now I have to convince my wife of that.

That is a 100,000BTU heater. A quick calculation of your pool size says that your pool would gain 0.69* per hour with that heater at 100% heat transfer. However, the 100,000 BTU is the input rate, not the output. That heater is probably more like an 80% output which would put the temp rise closer to 1/2* per hour.

It just keeps getting worse and by time I pay for a gas line to my heater I'll have about $600 invested in something that won't work. Now I'll have to talk her out of it and convince her that it won't work.

Also remember you are taking a chance on a "used" piece of equipment. It could work today but not tomorrow.

Also, if you went with a heat pump you have to run a dedicated 240v line for it. So don't forget to include that cost if you are considering a heat pump.

Yeah I know buying used is a bit of a gamble but I really can't afford right now to spend $1500 to $2000 on a heater and I was looking for an affordable solution to keep the wife happy. I'll checking Craigslist and look for a deal sometimes you never know what will pop up.

For a pool that size you should look for a 300,000 BTU heater to get a roughly 2* temp rise per hour. Agai, a lot of factors will come into play here such as heat loss dependent on ambient air temp, solar cover, etc. For example, on a 85* day a pool of 85* water will not lose any heat

Don't rule out solar panels yet my friend! Indiana HOAs don't have much of a leg to stand on regarding installation of solar panels. They may SAY they do, but Indiana Law says otherwise. Read this to get a feel for your rights --> http://www.in.gov/legislative/ic/code/t ... 7/ch2.html You'll easily get a payback in a few years over using gas. Solar panels PLUS a blanket = extended swimming season!

Best of Luck to you

I was thinking of using 4 2x10 panels to start. With them being smaller it would be easier to use them on the ground behind the pool. I am really against putting them on the roof. If I had a single story I would consider it but having them two stories in the air is something I don't want to mess with. Not to mention the wife thinks they are ugly but I have I have not completely ruled them out I'm just trying to get creative with the install. The back of the pool faces south.

To give you a feel for appearance, here's a pic of my roof solar at my former home. The panels are Heliocol and notice how they conform to the roof vent protrusions. Those panels faced dead-on south and I had other panels on the west facing side.

It looks good but I am going to install this myself and I really don't want to install on the roof. By the way I would like to thank everyone for the all the helpful information.

Are the solar panels listed on eBay all about the same quality or should I be looking somewhere else? I am going to start off with three 4x10 panels and see how that works. I am just going to lay them on the ground behind the pool.