FAQ: Cheaply Keeping a Pool Hot -- 90F,95F,100F -- How we ran till Jan 11th in Canada

[Swampwoman]

Hey mdre, come open my pool We just had a ridiculous dump of snow last night, and candyarse that I am we're not opening til the 18th when it will supposedly be spring again

But I will think of the fun you're having while I watch my wintery scene from the hot tub this morning!

I have a friend near Sarnia who just finally got himself a pool heater a year or so ago. I'll have to take a screenshot of your gas bill and opening. I already tease him that he opens so late

 

[mdrejhon]

Today was a pleasant swim in relatively warm 18C/65F sunny weather and an 87F pool (95F tomorrow) but check out our swim in a blizzard last Sunday:

Snow accumulating in my hair!

Who sez you can't swim in a snowstorm!?

We even built a poolside mini-snowman while in the pool, as the snow was accumulating fast within reach.

It was just like a Nordic spa, but in our backyard!
(They have large near-pool-size hottubs too, that they run even while it is snowing).

The poolside snowman melted the next day though!... Now today it's finally spring weather.

 

[mdrejhon]

Looks like within 1-2 years we'll begin pulling out a pool dome instead of a pool-closing winterization cover....

 

[mdrejhon]

Also bumping this thread to mention that my old LAARS LITE 2 heater is going to be replaced with what is probably Hayward ED2 heater (H250BTU). The inlets/outlets threads are currently leaky and is generating one bucket of water an hour, would cost 500 dollars to replace. So we're replacing the whole heater.

Incidentally, our pump is a very old fixed-speed 1.5HP pump, so we'll replace it with a new modern electronically-controllable variable speed pump -- probably a Hayward pump too.

Incidentially, both the heater and pump we're considering, are supposedly compatible with Hayward automation add-on products (apparently this future-proofing costs only $100 extra for the pump, via "ProLogic" compatibility), so we have the option of buying additional autmoation products later, to allow being able to turn on/off the heating/pump simultaneously more easily by remote control (iPad, iPhone).

I am open to other ideas of a pump-heater combo, but let me know within 48 hours before we commit to automatable Hayward products... (approx $4K CDN budget ballpark)

According to local pool stores.... We are slowly probably going to become the first Hamilton lower city residence to run their full-size outdoor pool yearround. They know of nobody else local running their outdoor pool the way we do!

 

[Swampwoman]

Hi there! No doubt you're the first on the winter operation front

I just noticed you said "ED2" for the Hayward Heater. Do they still sell that model in Canada? My old heater was an ED2 and lasted for 15 years, which is outstanding...but another poster here says the newest Hayward line (HFD series I think is what they're selling here) have more things that can go wrong, and likes Raypak for trouble-free operation.

Here's a link to my thread on that, where I ultimately purchased a 266btu Raypak with cupronckel from Swimming Pool Supplies, Pool Safety Cover, Swimming Pool Covers, Swimming Pool Pumps, Pool Pump Parts - INYOPools.com
- it was a good experience. Troubleshooting 15 y/o Hayward H 200 Leak/IF code

However, with automation in play, you may be better off sticking with Hayward. Plus, with indoor operation (believe you said previously yours was in a pool house or utility shed?) I think it extends life/reduces problems.

Can't wait til you get YOUR dome so I can get heating-bill-reduction tips from you
To that end, I've just made an "in-pool" solar roller system thanks to TFP DIY ingenuity over on another thread: DIY Solar Cover Roller - Page 6

My "2-part-toilet-paper-roll" design variation is to allow me to easily roll up 1/2 in pool and move it out of the way during physio in wintry air conditions inside dome

Last night I used your "still water" logic and turned off my heater just to see how many degrees I'd lose overnight...was at 89 when I shut down, and am now at 87ish, so not bad! Then again, wasn't much lower than 50 outside...

I've got to wait another 3-4 weeks before my dome arrives so I'm trying to conserve energy since I'm not closing the pool.

 

[mdrejhon]

Good to hear! Yes, the stationary water does cool down noticeably slower, doesn't it!

Just make sure you stir it up a bit (10-15mins, pump run, preferably heated to prevent cooling effect occuring) before making a good start-temperature reading.

Sometimes it is 87 on top surface and 80 at bottom of the pool. So if deciding how many hours you need to run heater to reach a target temperature, you need a stirred (average) reading...

 

[Swampwoman]

Hello again. While my dome is being born, I mean, made, I'm chewing on some other wintry issues. I may post a separate thread, but thought it made sense to ask you here.

1. I know your equipment is indoors. Is any f your PVC exposed on its run to the pool?
(Mine is and I'm wondering how long I can have pump shut off with hot water in pipes before I risk freezing.)

2. When you "closed down" for a few months, did you blow the lines - maybe I just need to go back and read again

Here's the pipes I'm stewing about..,thinking about either insulating and adding pipe warmer then boxing it....but hubby is not in love with me using heat tape due o fire concerns and pipe heat tape is meant for indoor use...it does have a thermostat and only heats to 45 I think )

 

[mdrejhon]

Yeah, you really don't want to turn off the pump in freezing weather with those exposed pipes... You'll have to either fix that or give up efficiency (pay more per month...)

1. I know your equipment is indoors. Is any f your PVC exposed on its run to the pool?

All pipes are all underground, so it's not a problem for me.

Yes (for now) we blew the lines during pool closing. We will again this winter. It's not fun when outdoors is snowing & freezing, though! We are considering not blowing the lines once we skip the pool-closing ceremony, but running automatic intermittent bursts of heater during freezing weather to prevent pipe freeze, as well as occasional low-speed pump operation. I read a post where someone in Oakville didn't even bother closing their pool through the winter... You definitely can't do that comfortably with exposed pipes though... Freezing can occur quick (in a matter of an hour) with exposed pipes like that, with no ground for insulative effect.

For underground pipes, we only need to run intermittent bursts of heating to preserve the pipes, since the warmed-up ground acts as insulation. We're not yet sure how often, but it probably needs only a few 15-minute burst a day for survival through a -25C freezing spell, if the pool is being maintained between-weekends >70F.

Here's the pipes I'm stewing about..,thinking about either insulating and adding pipe warmer then boxing it....but hubby is not in love with me using heat tape due o fire concerns and pipe heat tape is meant for indoor use...it does have a thermostat and only heats to 45 I think )

Definitely warrants a little bit of insulation for efficiency if you want hot-tub temperatues while those pipes are covered in snow.

-- Inefficient: These uninsulated pipes are going to act as a refrigerator for flowing water in winter, reducing your heater efficiency.
-- Bad: These uninsulated pipes will freeze quickly when you stop the pump during subzero temperatures.

Heating wire (roof de-icing wire / pipe heating wire) -- laid parallel to pipes -- is another technique of keeping pipes from freezing
So it's in your favour to solve this if you plan to hottub a swimming pool during winter. Could be a housing cover and some plain insulation (fiberglass? homemade wood with built-in Tyvek panels? Etc). Cover it up may actually be preferable to wrapping the pipes, since a cover can be designed as removable to satisfy your husband. It could even be a (possibly removable) shelter/cover for that breakout mess, with a simple heater, like heating wire, (or similar) inside to keep the pipes from freezing.

Basically you could rig a separate thermostat to control the heater wire, put the thermostat sensor inside the interior of your pipe-shelter (but away from the heating wire) and use the thermostat maintain the inside of the pipe shelter to say, 40F just for freeze-prevention -- it keeps your electricity bills low, gas bills low, prevents frozen pipes, and greatly reduces refrigration effects. Run the heater wire along the pipe. Put the thermostat temperature sensor at the coldest part of the pipes, perhaps opposite away from the heater wire. (You could buy a cheap Kill-A-Watt to monitor if it's cycling-on-off properly). The heater wire would never operate unless temperatues next to the pipes fell below 40F or so (like stationary water during subzero temperatues). Cheap. But it is a lot of work to build a minishelter for your pipes, and install pipe heating via a run of roof de-icing wire parallel to the pipe. Even unheated shelter would be better than nothing, too.

Simple shelter like a large semi-circle plastic cylinder cut lengthwise & put on top of the pipes as a protective dome for the pipes -- could be easier than insulating every single pipe. Very simple shelter, no insulation, inside of shelter heated only by heating wire. You can easily put heating wire is reasonably cheap, easy, and you should run them along the pipe lengthwise. Also Make sure you use GFCI for safety's sake.

You could also just redo the pipes to run underground too, but that's a lot more work than any option (insulation, and/or shelter for pipe run, and/or heating wire).

How long is your above-ground pipes?

 

[Swampwoman]

Just the width of the sidewalk, then they go underground. The polebarn (reno'd to pool house) and sidewalks were here long before the pool, I suspect, and locating the equipment indoors meant not breaking the cement slab it was built upon, or a least that's my guess.

Hubby and I discussed further today plans to build a shelter next week.

I used a fireproof insulation foam board called Thermax by Dow a few years back to re insulate our crawl space...I'm thinking I'd use that to line the inside of the pipe shelter...super high r-value but can handle hot pipes nearby (both sides are foil-covered and it passes spec for same.) The outlet next to the pipes is GFCI, so with a thermostat-controlled pipe heat wire rated for PVC, I could clamp same to pipes.

If we find the dome inoperable/impractical in Jan/Feb, dome mfg recommends just dropping heat to 40 and deflating, letting same float on water and sing cover pump or snowmelt. So I probably wouldn't dare actually turn heater off completely unless I was going to blow out the lines.

The next thing to think about is what to do (besides pray) in a power outage

 

[mdrejhon]

Since our pool season is now 10 months long....

...I am deciding whether we'll skip pool closing this year. (chlorine still maintained & pumped, with intermittent heat boosts to prevent pipe freeze).

I am wondering if anyone of you have any experience skipping the pool closing/opening through the winter in a climate that can reach below zero (-30C).

We don't have a pool dome yet. But our pipes are underground and the pool has never frozen over, even in the coldest -30C freezing spells. So we only need minor daily heating boosts (15 minutes per day) to maintain the pool at maybe 35-40F. This can be done automatically on a schedule or thermostatting (if new heater thermostat can go that low) If we skip it together and simply maintain the pool at ~35-40F temperature (using small daily heating boosts lasting 15 minutes a day) to survive February unused, we can skip the pool closing and pool opening, and rapidly take advantage of warm weather forecasts (like above-zero weekends).

- Pool shed is heatable and will have a freeze-protection electric heater installed this winter. It will allow thermostatting the room to, say, 40-45F (~5C). Also, pool heater tends to heat up the room too. It's also a workshop room and a smoking room (guests...I'm a nonsmoker) so it has a need to be heated up in the winter; the pool heater provides bonus heat above-and-beyond.
- Variable speed pump will be already installed; it can run at minimum speed operations to keep pipes from freezing.
- New heater will be already installed; it can run 15 minutes a day during the coldest part of winter to maintain a range of 35-40F.

Given this scenario, pool would be put into maintenance "statsis" in January when it feels 'expensive' to hottub a pool (e.g. sustained freezing days). Winter cover might be put on for safety's sake, but no draining and clearing up pipes, and possibly skip the pool closing chemicals. Maintain chlorine through the winter once a week testing water via the skimmer. Pool would be heated right back up in March when daytime temperatures started going above zero again. Our experience was that it was a relatively easy pool vaccuuming after the winter, as pictured above. This would reduce effort, and possibly stretch our pool season even further (say, up to about 10.5 months) without the need for a pool dome yet.

We have not decided yet, keep tuned.

 

[Swampwoman]

I think the trick will be to never let it lose enough heat to be in the 30s...so you'd need a strong sense of degree loss by temperature in the event of a power outage (unless you have a whole house generator). And then add a buffer of temp. But essentially, by not closing, you'll have a smallish daily cost to boost to cover your daily loss wherever you draw the line at dropping...eg I'm thinking in your shoes I just might maintain at 50 or 60 to have room for error.

As you know, this buffer is occupying my mind at the moment for when the dome comes

Right now I'm charting degrees/therms or CCF used without dome but with cover etc to get a sense of winter bills. Last night was 37 degrees but much warmer during day. So I really only lost 6 degrees in a 15 hr period of still water, meaning I fired up the heater at midnight to get back to 95 for physio this morning.

Currently, 6 degrees takes roughly 6 hours with my 266k btu 80% efficient heater for a useage in my 24,000 gallon pool of about 200,000 btu/hr, so my night heat up cost will be about 12 CCF x .70 cents per CCF or $8.40. We'll see how much I lose and how long it takes to recover when the temps are solidly below zero, but I know my hourly heat cost can't really exceed 2.12 therms per hour (which in my case, is a little over $1.40) because that's what the heater is rated for.

So, the majority, eg 70 percent of heat loss is evaporation, handled mostly by cover. According to the link I'll post, the balance is conducted loss. If you knew how long it took your pool to drop from 95 to about 50, you'd have a sense of rate against which to heat, and buffer if you lost power for a few days.

Here's a cool heat cost calculator you and those reading your thread might enjoy... SWIMMING POOL ENERGY TEMPERATURE CALCULATOR | Neil Anderson

 

[Mickey Moose]

I don't heat my pool all Winter but I do heat it to 95F for a couple-few weeks at a time when I do. Your post has me thinking and I'm curious now. I wonder how much it costs me though I can't say my bill ever increased enough that I thought twice about it.

Thanks for sharing.

 

[mdrejhon]

We opted to keep the pool heater route, not the boiler.
-- Raypak Digital 266 is installed.
-- Tristar VS Pump is installed.
Took a lot longer than expected, being without the pool for over 2 months, so it's good to swim again.

Poolside snowman time!

December 11th, 2016
Temperature of 95F (actual water temp from thermometer in water) and 100F (displayed on Raypak thermostat)

I now have modified pool operations. During below freezing I have to prevent pipes from freezing, so I run the new Hayward Tristar VS pump at 1000rpm minimum speed (appears to move less than a pound of water per second; and consumes only 50 watts) -- to prevent pipes from freezing. Slowly trickle the water through the pipes without cooling down the pool too much.

We calculate we can overwinter (2-3 months of electricity/gas) for less than the cost of a serviced pool store closing
We are possibly going to attempt skipping the pool closing this year -- we will decide by Christmas/New Year.
-- We'll keep the pool mostly unused at babysitting temperature of 65F (or 40F during cold spells), but "ready to fire up for a weekend" to 95F
-- Pool maintained but have the winter cover on. Two covers in use concurrently (bubble foam cover underneath)
-- We'll flip over the winter cover halfway during warm winter weekends, and have half the pool open for mid-winter swimming (once or two weekends a month, at about $75 natgas to boost to 95F during milder winter weekends)
-- Soil thermometer will allow us to monitor whether it's safe to stop the pump to preserve the heat in the pool. But we'll have to pump without heater during longer freezing spells
-- Between weekendsm heater maintaining ~60F and trickling the water through at super low speed (50 watts power consumption) to prevent pipe freeze
-- If there's a long cold spell, we'll let the pool temp fall to around ~40F and keep pumping 24/7 at trickle (1000rpm). Both covers on at same time (bubble wrap cover on water, and winter cover hovering above).
-- There is darn near zero chlorine consumption in the pool below 50F. Chlorine remainend 5ppm for 2 weeks. Chemical costs will be fairly negligible.

In 1-2 years we'll have to get the inflatable dome, but we have determined it's economically viable to skip the pool closing / pool winterization.
-- $200 to maintain the pool (minimal 50W electricity / minimal natgas) for 3 months before next pool season
-- $500 to maintain the pool AND have a few pool-size-hottub weekends (cost of natgas + cost of electricity)
These are our estimated costs of attempting to overwinter our pool without closing it.

Professional pool closing cost about ~$300 where I live, so this is a homer simpson nobrainer for us (unless we actually want to attempt an uncomfortable pool closing mid-winter).

Final GO/NOGO decision soon.
Keep tuned...PoolMath

 

[Swampwoman]

I was just thinking about you yesterday during our snowstorm

We've gotten more than 8" but given pace of it, the dome did not go down. I lost 4 degrees in 12 hours with the heater off, so recovered it pretty easily

My only suggestion for your set up would be to give yourself enough temp buffer to account for a power outage by tracking cooling rate in seriously subzero temps. Or do you have a generator that can run the poolhouse? (We just got one and are awaiting electrician to install interlock kit.)

Formula I came across is temp differential in F Degrees times surface area SF of pool times 5 btu per hour.

In my case it takes about 200,000 btu with my raypak 266 in 24,000 gallons to get one degree in ideal condition (mine is cupronickel exchanger which only gets me 240,000 input).

So with 30 degree weather were it not for dome differential in air temp, from 95 would be 65x600x5=195,000 btu or the equivalent of a degree an hour.

However, with cover and dome, my average has been less than 1/3rd of a degree...but air dome interior temps haven't been lower than 40s yet and more frequently 50s and up.

That may change this week since it will get down to 5 degrees tomorrow then 0 degrees the next night. So even if the air temp inside dome stays, lets say 25 degrees warmer (have seen differential this high) I will still be at the degree-an-hour loss rate. Am hopeful that the cover will interrupt that by a good 70% but we'll see In essence, I hope to not run heater more than 50% of the time, which would be about $16.80/day.

I wish I had a vs or 2 speed pump, as for saftety sake I am running pump 24/7 given above ground pipe section. Yesterday during storm the sensor inside the insulated box still read 65 degrees...heat is from the water temp circulating.

At any rate, enjoy! If it helps you decide, I will report back on my own heatloss rate during cold snap!

 

[mdrejhon]

We are still running the pool through the recent snowstorms and figuring out best double-cover operations. I think we are trying to figure out what has best efficiencies (e.g. 1750 RPM at 200W electricity but less natgas heating efficiency, versus 3200 RPM at 1000W electricity but better natgas efficiency) as we have TOU electric rates. I may jerryrig an automation system in a hurry, but maybe not just yet.

About your dome...
The dome probably makes vaccuuming easy, I still have to vaccuum debris, so winter cover will eventually go over it.

For your pool dome, how are the chloramines (super strong chlorine-like smells) in an enclosed space? (Asthma flare ups). That is where an ultraviolet disinfection unit plays wonders in making an inflatable dome more comfortably breathable for problematic pools amd large numbers of swimmers. As that breaks down chloramines far faster than chlorine, if your ventilitation is kept to minimum to keep air inside the dome from becoming cold. Thats what I heard from several sources and from a public pool that used inflatable dome...

 

[mdrejhon]

BTW.....

Water resistant battery powered app-color-programmable Christmas Lights unreeled while I am inside the pool!



The string is a USB plug but the rest is IP65-rated and perfectly fine for the pool edge at low 5 volts. Just get a USB power bank (portable USB battery used to charge tablets and phones on the go)m plug the lights in, and then ziptie the USB battery in a sandwich bag. Battery powered lights lining the pool for cheap compared to commercial pool products!

 

[Swampwoman]

Cool! Something new to play with

Re:

For your pool dome, how are the chloramines (super strong chlorine-like smells) in an enclosed space? (Asthma flare ups).

I've been surprised on this front as there really don't seem to be any, at least that i can detect. However, in our installation, the blower is circulating air at least 50% of the time, eg every minute. That's likely in part because on our custom shape there are lots of bends where minute amounts of air escape (the vinyl flap does not necessarily "seal"). This means in theory that we may be on the higher end of the scale in terms of electric use for the blower, which is a 7 amp draw, but I did the Calc at even at 100% it wouldn't be more than $80/mo here, so I don't worry about it. I don't know if short cycling that that is great for the blower, but time will tell.

The other reason for non-chloramines air, I suspect, is that I do still run at TFP max, eg for my swg at cya 80 stay around 6, and most days I am the lone swimmer, not using body products, not wearing a suit, and with no contamination from external debris...so I don't think there's a lot of material with which to produce ccs. My bubble cover is transparent and I do get sun, amplified in fact, through the clear sides of the dome in the early part of the day in its location.

So your future mileage may vary, but climate inside the dome here is pretty nice. I was worried it would smell like a hotel hot tub, and that's not the case at all.

 

[Uavmx]

Super helpful thread! I just got my heater working, new solar cover coming in this weekend, so I'm going to try this for the first time ever over the holiday as I have friends/family coming to visit.

First question: When doing the initial 24-48 hour increase (I think need to move it from 50-95) is it best to run it 24 hours into the cold night? Or shut it down at night and only run it during the daytime hours. Let's assume I have plenty of time (4-5 days) to heat up the pool if I want to.

Secondly: Do you run your pump at full speed? I have a VSP, currently it needs to be running full to get the heater to see the pressure (but I think I can fix it if needed) is there value in trying to run it a little slower?

 

[Swampwoman]

Hopefully mdr/Mark will pop in with his experience on the run up - as my methods are not presently in open air, though I did run open through very low temps before installing the dome.

How many BTU is your heater? If your temps are above freezing, which they sound like they are, I'd run the heater on max until you get to your desired temp...with pump on full if your heater needs the pressure to operate (low flow causes problems in heaters). The key is to NOT thermostat on the run up...run full to max.

While night means the ambient air is colder, and your temp gain might be a bit slower, I've not noticed a huge differential -- here where its below freezing, I actually run the heater only at night to gain back the 5-6 degrees I might lose during the day. In my case, I run at night because I want it to therapy temp for the am (95 degrees) but can still comfortably swim during the day without the heater on as I only lose 1/3 to 40% of a degree an hour depending on how far below freezing I am. As a result, my heating time and ergo cost can be as low as 5 hours up to the most I've needed in bitter cold of around 10 hours.

Once you're at desired temp, leaving the water covered and still until use seems to preserve heat the best. But in my case I keep the pump running to operate my air blower warmer that uses the pool water...and to avoid any pipe problems in an area exposed that comes out from the pool house. In your shoes if I had the option, my daytime, non-heating hours would be run on low speed. But i only have a single speed pump.

Best wishes for an awesome swim holiday

 

[Rollercoastr]

For your pool dome, how are the chloramines (super strong chlorine-like smells) in an enclosed space? (Asthma flare ups).

The "hotel pool smell" / chloramines was my #1 concern, even before I found TFP or had ever heard the word chloramine. (the pool is the center of my home) Odor is 99% a non-issue for me, and it would be 100% if I weren't still somewhere along the TFP learning curve.

Last month I was in the midst of showing-off my TF100 kit and the condition of the pool in general to a guest when I proudly walked him over to the pool and mentioned the lack of odor. He agreed and said, "yeah, I can barely smell it at all!" I nodded and tried to disguise the cold panic I was feeling about his use of "barely". I had stopped testing for CC's because the results were so predictable: none without a swim load, and under .5 after swimming. I keep the pool covered whenever it's not in-use, but I realized that it needs to regularly breathe. Sometimes I only peel back part of the cover and briefly exchange some air. It seems to be doing the trick - no-one has used "barely" since.

I shut-off the heater 2.5 weeks ago because of wkd commitments and in preparation of heavy usage over the holidays. It bottomed-out at 66°, FC leveled impressively and CC's have been of course 0. Pump runtime has been at 2.5 hours per day. I was tempted to dial that back even further since the pool was cool and clean, but I chickened out.

I've missed swimming! I fired-up the aging heater last night and set the stat and the pump to full-bore. I would like a slightly bigger heater and a 2 speed pump, but I hadn't considered the issue of low-speed not satisfying the pressure requirement of the heater. That's good to know.