cfherrman
TFP Guide
I get more sun than Ohio, and it would take a couple of days of full sun to go from 77 to 80
Tankless Water Heater to Heat My Pool
- Thread starter stewbets
- Start date
Out of curiosity, how much are you invested in this setup including plumbing, pumps, the heater, etc.
Great experiment btw!
Great experiment btw!
Just to add to how much energy the SUN adds to the pool here is what I get. I track it daily. I get full sun from sunrise to 3:00PM, and then shade starts to hit and becomes 75% shaded by 6:30PM. I generally go up 4-5 degrees on the best days 6AM until 7PM. I typically lose 2 degrees at night. That is based on 60 LOW temp and 80 HIGH temp. I am at 43 degrees latitude.
If you want to do more calculations - you can use a weather underground PWS (Personal weather station near you or maybe add one in your backyard) and track INSOLATION (Incoming Solar Radiation) to calculate how much heat is gained from the sun. This is mine - PWS Dashboard | Weather Underground
I do not start purposely cooling my pool until it hits 90 degrees, which almost never happens. MY purposely cooling I mean keeping the cover off, and letting it free cool. My pool has never been more than 91. 86 is its normal temperature. I
If you want to do more calculations - you can use a weather underground PWS (Personal weather station near you or maybe add one in your backyard) and track INSOLATION (Incoming Solar Radiation) to calculate how much heat is gained from the sun. This is mine - PWS Dashboard | Weather Underground
I do not start purposely cooling my pool until it hits 90 degrees, which almost never happens. MY purposely cooling I mean keeping the cover off, and letting it free cool. My pool has never been more than 91. 86 is its normal temperature. I
Thanks for the info! I'll have to look into that. I tried to keep the heater off today to get a baseline, but I knew I wanted to swim in the evening and caved. I watched the temp from 8:00 AM till noon and it stayed steady at 77 degrees. That's when I turned on the heater. The water was 86 degrees when I got home at 5:00 PM. I've mentioned before that the resolution of my WiFi thermometer isn't the greatest, but it was reporting 86 and I verified it to be accurate with an analog thermometer.
$80 - heater
$40 - gas pipe and fittings
$30 - pump
$15 - vent stack and cap
$14 - timer outlet
$12 - wifi thermostat and temperature probe
$10 - pvc pipe and fittings
That puts me at just about $200 exactly. There could be a few random things I forgot, but that's pretty much it.
I shot a video of my setup tonight if anyone's interested:
OK, I've got some more data to share. The past 2 days were similar. Both were mostly sunny. Tuesday had a high of 84 and Wednesday a high of 89. On Tuesday, my pool temp started at 77 and ended at 86 with 5 hours of heater run time. On Wednesday, the pool temp started at 81 and ended at 86 with no heater. So, on Tuesday I'm going to conclude that the sun added the majority of the heat (5 degrees) and the heater added the rest (4 degrees). It's easy to trick yourself into thinking that sometimes the heater can produce better results, but it's always adding a fixed amount of energy to the pool, with or without the help of the sun and other factors. The results from these 2 days make sense when comparing them to my measured gas usage and the BTU's represented vs. the 8,000 gallons of water in my pool.
Thought I'd post a little update. Obviously the heater hasn't been used too much these past couple months, but it's still working great when we need it. It ends up getting used mostly when we night swim. I like the water to be around 86 degrees during the day, but while swimming at night we get chilled a lot more quickly, so I bump it up to 90 degrees for those occasions. Some may think that's way too hot, but we love it. My favorite part about this setup is the ability to control it from anywhere with my phone. It ends up getting used more because of the convenience.
Probably the only thing I'm not crazy about this setup is the rust coming from our heater pump. It a very cheap pump and I came across other reviews that mention the fact that it rusts internally. If I leave the heater off for several days, the rust seizes the pump and it needs to be manually rotated a couple turns to break it loose. Because of this, I setup a schedule to run the pump for a couple minutes everyday. Anyhow, there is a cloud of brown water that enters the pool for 5 to 10 seconds everytime the pump is turned on. I'm wondering if this is going to lead to an iron problem in the pool at some point. Has anyone experienced this issue before?
Probably the only thing I'm not crazy about this setup is the rust coming from our heater pump. It a very cheap pump and I came across other reviews that mention the fact that it rusts internally. If I leave the heater off for several days, the rust seizes the pump and it needs to be manually rotated a couple turns to break it loose. Because of this, I setup a schedule to run the pump for a couple minutes everyday. Anyhow, there is a cloud of brown water that enters the pool for 5 to 10 seconds everytime the pump is turned on. I'm wondering if this is going to lead to an iron problem in the pool at some point. Has anyone experienced this issue before?
Flying Tivo
TFP Guide
- Jan 24, 2017
- 2,926
- Pool Size
- 7500
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Just take a water sample to PS to get tested for iron so you can keep tracks. I'll suspect it will take a long time for it to be a problem with the water. On the other hand the stains if the rust is left sitting on your vinyl is the problem.
Thanks for the response. Monitoring the iron level makes perfect sense. There have been no rust spots on the liner anywhere that I've seen.
We haven't used the pool all that much this past month, but we fired up the heater last weekend for some night swimming. It's still working great.
It looks like today is going to be the last day of swimming for us this year. The forecast is calling for much cooler weather over the next 10 days. And even though this week has been hot, the shorter days and cooler nights have kept the water temperature under 80 degrees. I scheduled the heater to turn on this morning at 5:00am and the water went from 77 to 86 in 10 hours. And after solar energy is removed from the equation, I'm still getting the same .7 degree/hour rise from this heater as I did in May. The two D batteries that power the ignition have held up. This system has been more hands off than I thought it would. And controlling and monitoring it with my phone is my favorite part.
I still think it's absurd that this thread is in the "Agree to Disagree" part of the "All Things Not Pool Related" section on this forum. That's quite a disservice to so many people who would benefit from the things learned with this setup. It's not only viable, but I'd say it's advisable to anyone who's handy. If money doesn't grow on trees where you live and you don't own 3 vacation houses, or you bought a cheap pool and aren't about to spend twice that on a heater for it, why not give this a shot?
I still think it's absurd that this thread is in the "Agree to Disagree" part of the "All Things Not Pool Related" section on this forum. That's quite a disservice to so many people who would benefit from the things learned with this setup. It's not only viable, but I'd say it's advisable to anyone who's handy. If money doesn't grow on trees where you live and you don't own 3 vacation houses, or you bought a cheap pool and aren't about to spend twice that on a heater for it, why not give this a shot?
I would make one recommendation to your amazing project. Rather then running the pool water through the heat exchanger of the heater, run the heated water through shell tube heat exchanger made for pool water. So you'll need 2 pumps. One to circulate from and to the heater and the other pump for the pool water. The two waters remain separate.
Yes, I remember that it was relocated from the pool equipment category of the forums.
Yes, I remember the post being relocated from the pool equipment forum category. I jumped into my 76 deg water yesterday afternoon for the last time this season (SE Pennsylvania); I started thinking about your experiment. I had to come back to the website to check on the progress...Well Done !
Yes, I remember the post being relocated from the pool equipment forum category. I jumped into my 76 deg water yesterday afternoon for the last time this season (SE Pennsylvania); I started thinking about your experiment. I had to come back to the website to check on the progress...Well Done !
I gave a lot of thought to that setup, but could not source a heat exchanger cheaply enough to make it feasible for me. Additionally, part of this experiment is a torture test of the water heater since so many people assume that pool water will destroy its heat exchanger in short order. And I certainly don't disagree with that hypothesis, but it is just that, a hypothesis, until tests like this are conducted. And with this water heater costing $80, it's fairly disposible should the pool water prevail against it. Obviously a second exchanger (and pump) would also add running costs and complexities to the system, and until I'm convinced it's necessary, I'll continue with the current, simpler setup.
cfherrman
TFP Guide
Yes, it costs $.25/hour (gas and electricity combined) and achieves a .7 degree/hour rise in my 8,000-gallon pool.