When to heat?

[shane4]

There can be 3-4 days in a row without anyone in my family using my pool as we are at school and work and in the evening the kids have their organized activities( soccer, gymnastics,etc). I have been in the habit of simply turning off the heater for days on end as natural gas is getting costly.

Now the kids are off school and will be around much much more. We live in southern Ontario (Canada) and so far, summer temperatures suck!!!!!!!

We keep our pool at 84 F. At the end of the day, I turn off the heater for the night. In the morning the pool can drop to as low as 74 F. My 266k BTU heater is over sized for the pool so it gets back up to 84 F fairly quick. Nice and comfortable for the late morning and into the evening.

Pool store installed a new Pentair Superflo VS pump and they had it set to at an rpm high enough to filter and heat over night. They suggested it is more efficient to maintain the water temp overnight despite plunging air temperature than bringing the water up 10+ degrees all in one shot.

No doubt, it is a cost savings to shut off the heater for days on end when not in use, but for regular use what experiences do you have?

Run heater over night or just when needed?

I do not use a blanket at night for several reasons (awkward shape pool, expense of the roller, not wanting to fight with one every day, etc)

 

[mas985]

I do not use a blanket at night for several reasons (awkward shape pool, expense of the roller, not wanting to fight with one every day, etc)

That's your problem. But there are solutions. Here is what I ended up and it is very easy to take off and not to bad putting back on: DIY Solar Cover Roller

Without a cover, you lose so much heat every night as you can see (~10F). With a cover you would reduce that heat loss to 2-4F. So you would save close to 70% in energy costs.

 

[Swampwoman]

Shane, I don't cover my pool at night in West Michigan (similar climate to yours) due to footprint and limited space and I can attest it is more efficient even in this circumstance and at 88 in my pool to just leave the heater (and ergo pump) on rather than to come back 10 degrees each day.

I did that for one season and hubby pointed out even with low night temps he felt we'd do tester with constant incremental heat and our energy bills essentially proved him right. The bonus is the ability to take a warm water swim first thing in am

Ps...most report no success but I use Cover Free and it does cut down on the heat loss...nowhere near a over, but it makes enough of a difference to use it.

 

[JVTrain]

When to heat when not covering the pool at night? NEVER? Sounds pretty wasteful to me.

 

[Swampwoman]

What's more wasteful? Having the sunk cost of a pool that you can operate from May to October and use and enjoy every day, or to have the sunk cost of a pool that you might only enjoy on a weekend in July and August?

Its a personal decision for each family and family budget.

His question, however, was whether it would take more therms to move the water 10 degrees each day in a single session, or to leave the heater on overnight. My belief according to my own experiment is that it is slightly more efficient to leave the heat on, with the side benefit of early morning use.

Efficient, of course, is relevant. No, its not comparatively efficient to using a cover But he wasn't asking if he should use a cover

 

[borjis]

If you get a lighter 5 mil cover it's fairly easy to deal with one person.

I guess if my gas bill was going high I would do that.

The solar panels i have work so well I only need them running on weekends.
But with the heat wave we had the pool was getting too warm!

I have not used the cover or solar for two weeks and it has maintained 82 degrees.

 

[ps0303]

Wow losing 10 degrees at night. I guess since you don't want to cover the pool it really doesn't matter when you heat it.

Enjoy!

 

[carveitup]

I'm going to offer a counterpoint to those suggesting that leaving the heater on is the most efficient. Heat transfer theory shows that rate of heat transfer is dependant on the difference in temperature. By this logic, colder water will heat faster than warmer water. By the same token, on a cool day of night, warmer water will lose more heat than cool water. Based on this, it should be more efficient to heat it up when you want to use it and leave it cool when you don't.
Here in Burlington, we also have time of day electrical rates so it is about half the cost to run the pump at night. So from an electrical use perspective, run the pump and heat the water during the night.

Even around here, I know a few people who have had great results with solar heat and a relatively quick payback. It may be something to consider in your case where a solar cover isn't a desirable option.

 

[shane4]

Thank you Swampwoman! Yes, our climates will be the same so your testimony seems realistic. I guess as long as the sun is shining and the ground can stay a somewhat constant temperature, heat loss during the day should not be that bad. Plus, electricity rates are higher. I will save on pump time at night, but was not sure where the best savings on gas would be. I will try your way and compare usage and see if I get the same results as you. Plus my wife likes the idea of the morning swims, so I think I dont have a choice (happy wife happy life )I have used coverfree but dont seem to notice a difference. With the old one speed Super pump I could not see how the ripples from the jets could maintain an unbroken "film" on the surface. Now that I can get slower speeds maybe I will give it a go again. As you pointed out, although I was not inquiring about covers, I must admit the hone made version detailed by Mas985I is intriguing........

Carveitup, I have thought about solar but the upfront costs will put that idea on the back burner for now since the big buy this season was the new pump. I have excellent sun on my southerly roof so it is an option. As you know, our summer temperatures are not too impressive, so it`s hard to figure out that most efficient operation. Curious, I see by your signature you are heating. How do you manage your heat process. I have to admit the heat loss factor/theory boggles my mind. Like another post I started about pump speed and heaters, I assumed a slower flow would mean hotter water with the same amount of gas, so better efficiency. But that is not right is it?????
I also see by your signature you use TF-100 test kit. Where did you get it from?

 

[danpik]

I have to admit the heat loss factor/theory boggles my mind. Like another post I started about pump speed and heaters, I assumed a slower flow would mean hotter water with the same amount of gas, so better efficiency. But that is not right is it?????

No, it is a little hard to get your mind around but, the faster you can put water thru the heater the more efficient it is. (up to a point) colder water pick up heat faster than warm water and is able to pick up more of it. Instead of thinking of the heater warming the water, think of the water trying to keep the heater cool. Would it be easier to keep the heater cool by flowing cold water thru it slower or faster. At a fast rate it can carry the heat away quicker

 

[JVTrain]

I also see by your signature you use TF-100 test kit. Where did you get it from?

tftestkits.net The best home owner test kit money can buy.



# Sent from mobile device. Beware of brevity and spelling errors!

 

[MirellaJoe]

here is another canadian in ontario, actually in aurora and i agree the temps suck here....i just purchased a pentair propane pool heater which is being installed next tuesday since the propane guy can only come then grr anyways i'm trying to figure this out too, when the perfect time to heat the pool is, kids are home for the summer and honestly i would like the pool warm all the time so i guess i need to turn it on at night? but i agree using a cover does help to keep the heat in, the past weekend was cool and rainy and usually my pool temp in the morning is 75 but since 2 days of coolness it dropped to 65. On those sunny days and not to hot i can get the pool up to 81 which for me is still cold but i do use the solar cover at night.


So should i use my pool heater at night, through out the night because that's when it usually cools down or during the day when we want to use the pool?

 

[danpik]

My take on this is...If you are going to keep the pool warm for each day then you might as well keep the heater on all the time and let the thermostat handle it. Lets say, for example, we have a pool with 80,000 lbs of water the water temp drops 10 deg each night. If we have a 200,000 BTu heater (80% efficient), it will take 5 hours of run time to bring the water temp back up in the morning. If we leave the heater on all night, or all the time, it will still run approximately the same amount of time to keep the water at that temp considering the demand load will be the same. There are some physics that get in the way of this, but for the sake of simplicity we won't get too deep into that.

 

[carveitup]

I got my test kit from tftestkits.net and had it shipped to a friend in the US. The Taylor equivalent is incredibly expensive in Canada.

I only heat very occasionally. With my solar cover, the pool will usually stay around 82 although with the two inches of rain we just got, it went down to 75.

The theory I spouted should give you the best efficiency from a gas use perspective. Running the pump on high would also be best but may be overcome by added electrical cost. I think from a practical perspective, keep it warm when you are using it regularly. If you're only using it sporadically like when the weather is bad, let it stay cool until you want to use it.

 

[shane4]

If you're only using it sporadically like when the weather is bad, let it stay cool until you want to use it.

seems logical as my family can go days without the pool. My daughter is the heavy user, but at 10yrs old she has no temperature feeling anyways. HAHAHAHAHHA

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here is another canadian in ontario, actually in aurora and i agree the temps suck here....

Hi neighbour! I am in Newmarket

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tftestkits.net The best home owner test kit money can buy.

Thanks, but they dont seem to ship to Canada

Curious, how many tests on average can one get from a TF100 kit?

 

[MirellaJoe]

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Hi neighbour! I am in Newmarket

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heyyyyyyy!!! wow i'm actually happy i found someone close by!!! cool

as for the test kits i bought my last year thank god since i bought them the store online closed down but i found someone who sales them taylor test but not cheap. No one will ship those tests here in Canada, so Richard is who helped me find the supplier for the taylor tests Lowry and Associates - Pool, Spa and Industrial Testing Products and they are in newmarket too!! but they arent cheap so just keep ur eyes open and hope someone else starts selling them.

 

[Swampwoman]

^lowrys has an exclusive distributorship in Canada ... Hence the ability to charge what they do.

Shane, if you have any friends or relatives, say in Buffalo, the TFP100 would be a great "gift" for them to bring to you I just took one to a buddy in Sarnia for a birthday gift

I haven't lived in Ontario since 2003, so I don't know your gas and electric rates comparatively. When I started "clocking" by pool heat use the first year (in 2012, new house) I gathered up the usage info from historical Aprils (when the pool wasn't open but the boiler generally off) as a baseline, and read my meter for a while (eg startup run time on the meter, versus constant heat). At that time, I was afraid of the cost, so was trying to gauge what I was spending

In my particular house, my overall seasonal usage to heat the pool is roughly the same as heating the home in winter via boiler, with "constant heat" now 2 degrees higher than last year (88 vs 86) meaning about a 10% boost over last year. We just kind of decided that we really like swimming late at night and early in the morning through the week since we work long hours, so it felt worth it. Does wonders for my arthritis...which is worth something to me at least

That said, if you can figure out a cover and are willing, by all means do it. At some future date I'll have to renovate the pool. At that time, an auto cover will likely be a worthwhile investment if I can make the footprint work. I need a button I can just press in the dark before going to bed, and press again in the morning

 

[shane4]

ooooooo, an auto cover, now that would be cool.
That is one thing I have realized, is that the pool heater is using about the same as the house furnace, so cost is relatively constant all year. Eh, it's only money right...... I'll just keep playing those lotteries

have you seen this sick display of money...... a deck that hides a pool below
Amazing Secret / Hidden Swimming Pool - A Creative Engineering By AGOR - YouTube

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Shane, if you have any friends or relatives, say in Buffalo, the TFP100 would be a great "gift" for them to bring to you I just took one to a buddy in Sarnia for a birthday gift

I assume you had no issues at the border????

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Lowry and Associates - Pool, Spa and Industrial Testing Products [/url] and they are in newmarket too!! but they arent cheap.

I sent them an email as I could not get their catalog to download. The fact their prices are not online tells me it is gonna hurt $$$$$

As they never replied, do you remember what they charged?

 

[JVTrain]

I'd love an auto cover too. But... on the neighbor's new pool (IG 40x20 steel wall, vinyl) it was about $11K with integrated rail!

# Sent from mobile device. Beware of brevity and spelling errors!

 

[jrguzmanr]

I don't understand how the auto-covers would work. I have a friend who has one and the rails are on the deck so the cover never touches the water so no heat transfer during the day and it's a mesh cover so air travels through it without a problem so I would think you still lose temperature overnight. Am I missing something here?