Pool heat pump - How many BTUs?

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I'm thinking of installing a heat pump for my 15x30 pool.
I'm told that the correct unit for my needs (an Aquacal TropiCal) puts out 112,000 BTUs (40 amps/5.8 KW). I'm thinking that a larger unit that puts o ut 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and require le ss time on, thus use, in theory, less electricity - but it's about $500 mor e expensive than the small unit. We'll probably only use the pool on the w eekends. Not sure how long it will take to break even on this with running it for only a couple days per week.
Anybody have any thoughts or opinions about this? Is my thinking skewed? Is it worth the extra cost?
Thanks!
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On 5/22/2013 6:46 PM, snipped-for-privacy@gmail.com wrote:

112,000 BTUs (40 amps/5.8 KW). I'm thinking that a larger unit that puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and require less time on, thus use, in theory, less electricity - but it's about $500 more expensive than the small unit. We'll probably only use the pool on the weekends. Not sure how long it will take to break even on this with running it for only a couple days per week.

Also think about an insulated cover for the pool.
Paul
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On Wed, 22 May 2013 19:16:40 -0700, Paul Drahn

112,000 BTUs (40 amps/5.8 KW). I'm thinking that a larger unit that puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and require less time on, thus use, in theory, less electricity - but it's about $500 more expensive than the small unit. We'll probably only use the pool on the weekends. Not sure how long it will take to break even on this with running it for only a couple days per week.

If you don't have a cover, forget about heat. I have a 330,000 BTU gas heater that won't keep a pool that size warm overnight without the cover.
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On May 22, 9:46 pm, snipped-for-privacy@gmail.com wrote:

t 112,000 BTUs (40 amps/5.8 KW).  I'm thinking that a larger unit that pu ts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and requir e less time on, thus use, in theory, less electricity - but it's about $500 more expensive than the small unit.  We'll probably only use the pool on the weekends.  Not sure how long it will take to break even on this with running it for only a couple days per week.

d?  Is it worth the extra cost?

get a natural gas heater or propane if its available.
electric will be the slowest and most expensive and definetely get pool cover.
if you live in the desert southwest get a solar pool heater.
the higher the BTUs the faster the warm up time, up to the limit of your main electric service
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On May 23, 2:46 am, snipped-for-privacy@gmail.com wrote:

t 112,000 BTUs (40 amps/5.8 KW).  I'm thinking that a larger unit that pu ts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and requir e less time on, thus use, in theory, less electricity - but it's about $500 more expensive than the small unit.  We'll probably only use the pool on the weekends.  Not sure how long it will take to break even on this with running it for only a couple days per week.

d?  Is it worth the extra cost?

You would be better getting some sort of solar heater.
Running a swimming pool is always going to be expensive. Gas would be far cheaper than electricity. Electricity is the worst possible option. If your pool is near the house you may be able to use the home heating furnace if you have a wet system. You need a good insulated pool cover. Ideally there should be insulation between the pool and the ground too.
The economics of turning a pool heating off are very dodgy as it takes days for the pool to reheat. Reducing temperature may be an option.
Your incoming power supply may not be big enough in any event. You may need a three phase supply.
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On Thu, 23 May 2013 00:12:12 -0700 (PDT), harry

112,000 BTUs (40 amps/5.8 KW).  I'm thinking that a larger unit that puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and require less time on, thus use, in theory, less electricity - but it's about $500 more expensive than the small unit.  We'll probably only use the pool on the weekends.  Not sure how long it will take to break even on this with running it for only a couple days per week.

Harry is right, solar is the way to go but if you are very far north, that may still not be enough.
Most of the pools in my neighborhood (SW Fla) are solar heated. The practical limit for an uncovered pool is really only about 10 degrees above the average daily ambient temp. You may end up with 80 degree water in the afternoon on a 70 degree day but by morning that will be back down in the low 70s. A cover makes a huge difference in that. My neighbor across the street has more collector area than pool surface and they can hold 86 or higher most of the winter (45-50f at night) When it gets much colder than that, they don't do as well.
I have less collector than pool area and no cover. The only thing solar does for me in knock the chill off in the spring and fall. I changed the plumbing so I can switch over to the spa. THAT is a heluva deal. When the solars are useless on the pool, I can still get the spa up in the high 80s or low 90s before I kick on the heater. In the spring and fall, I can get all the heat I need from the solars in the day and only need the heater to maintain the heat until I am done with it We do not heat the spa with the heater unless we are in it.
Typically the only controller on a solar pool heater is a timer on the pump. I am going to tie the spa solar into the thermostat tho because this spring I caught it at 120 ;-)
Harry You virtually never see 3 phase at a residence but we do see 400 amp single phase service on a big house.
As gee whiz info, my wife's country club has 7 heated pools, uncovered. They can't hold the temp with 10 ton heat pumps on the small pools if we have a cold snap. The big pool has 30 tons
I will try to get the cost, they are all on separate meters.
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On May 23, 1:12 pm, snipped-for-privacy@aol.com wrote:

LOL give harry a break. He sees the 3 phase service at the nut house he's been committed to and thinks it's a house.....
It's not an electric resistance heater, it's a heat pump. A unit in the size the OP is talking about runs on 240V 50 to 60A circuit.
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On May 23, 6:12 pm, snipped-for-privacy@aol.com wrote:

out 112,000 BTUs (40 amps/5.8 KW).  I'm thinking that a larger unit that puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and req uire less time on, thus use, in theory, less electricity - but it's about $ 500 more expensive than the small

w long it will take to break even on this with running it for only a couple days per week.

ewed?  Is it worth the extra cost?

Most houses here have electricity here is at 230volts/single phase/ 100A. There is no 120 volts except on construction sites when step down transformers are used.
However if you have more than say 15Kw continuous heating, you will be expected to get three phase (depending on location).
Electric heating of swimming pools is virtually unheard of due to cost, there is a gas supply to 99% of places.
Outdoor pools are uncommon here, there's probably only ten days/year warm enough to use one.
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On Thu, 23 May 2013 22:04:24 -0700 (PDT), harry

You are there and we are here. Different all the way around.
Nobody gets 3 phase in a dwelling unless you are Al Gore. They don't even have a 3 phase primaries on most residential streets We also have one transformer per every 2 or 3 houses. UK does that differently. I know a few UK electricians and inspectors. On our contractor BB we have separate forums because very little actually translates. The topology of the wiring is different (no rings here), the overcurrent protection scheme is different (no fused plugs), the voltage and frequency is different, ground fault protection is different (GFCIs on each circuit, not a RCD on the feeders) and the color codes are different.
Electric heaters are heat pumps and compared to propane, they are usually cheaper. Natural gas is probably cheaper than either, depending on where you are.
We both agree solar is the way to go. I have a gas heater, I think we have used it 2 or 3 times in 4 years. I have even migrated my spa to solar ... an excellent deal.
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ts out 112,000 BTUs (40 amps/5.8 KW).  I'm thinking that a larger unit th at puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and r equire less time on, thus use, in theory, less electricity - but it's about $500 more expensive than the small

how long it will take to break even on this with running it for only a coup le days per week.

skewed?  Is it worth the extra cost?

I'm sorry for you harry. If true, just another sign of the inadequacy of the Britts.
 There is no 120 volts except on construction sites when step

Who cares? The pool heat pumps all run on 240V.

That's just 62 amps. What exactly is the problem with having a 150A service that makes 3 phase necessary? 150A services are very common here, the min pretty much that's put in today for a house. 200A are very common too. A friend has 300A. All those are done using single phase, nothing unusual at all.

It's not really electric heating. That terms is typically used to refer to resistance heating. The pools use heat pumps, which are referred to as heat pumps. If gas is the only viable option in the UK, how do you explain this:
http://www.dreamheatpumps.co.uk/
http://www.ebay.co.uk/itm/350793470032
http://www.lighthousepools.co.uk/
Like I said, if they let you out of the nuthouse at least once in a while, maybe you'd see some stuff.

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wrote:

puts out 112,000 BTUs (40 amps/5.8 KW).  I'm thinking that a larger unit that puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and require less time on, thus use, in theory, less electricity - but it's abo ut $500 more expensive than the small

e how long it will take to break even on this with running it for only a co uple days per week.

g skewed?  Is it worth the extra cost?

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A 15Kw three phase system here is just 22 A/phase as the voltage is 410v. Putting loads like this on a single phase system causes voltages to appear on the neutral which can upset RCD devices.
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) puts out 112,000 BTUs (40 amps/5.8 KW).  I'm thinking that a larger uni t that puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker a nd require less time on, thus use, in theory, less electricity - but it's a bout $500 more expensive than the small

ure how long it will take to break even on this with running it for only a couple days per week.

ing skewed?  Is it worth the extra cost?

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Only if the single phase system is half-assed. Apparently that must be the case. And all this time I thought you Britts were so superior. Most houses only have a 100A service and if you need more you have to go to 3 phase. Must be a grand place. Or, more likely, your're just BSing as usual.
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wrote:

al) puts out 112,000 BTUs (40 amps/5.8 KW).  I'm thinking that a larger u nit that puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and require less time on, thus use, in theory, less electricity - but it's about $500 more expensive than the small

sure how long it will take to break even on this with running it for only a couple days per week.

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A 100A supply is 23Kw. here. Why would you need more than that?
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On Fri, 24 May 2013 23:17:08 -0700 (PDT), harry

puts out 112,000 BTUs (40 amps/5.8 KW).  I'm thinking that a larger unit that puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and require less time on, thus use, in theory, less electricity - but it's about $500 more expensive than the small

how long it will take to break even on this with running it for only a couple days per week.

Oh, things like electric ovens, air conditioners (or heat pumps), electric water heaters, clothes dryers. Any number of things that makes life comfortable, which you Brits obviously haven't heard of.
Like I said in another post, I have two 150s (72kW). In my other house it's only a single 200A (48kW) entrance.
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On May 25, 3:10 pm, snipped-for-privacy@attt.bizz wrote:

piCal) puts out 112,000 BTUs (40 amps/5.8 KW). I'm thinking that a larger u nit that puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and require less time on, thus use, in theory, less electricity - but it's about $500 more expensive than the small

re how long it will take to break even on this with running it for only a c ouple days per week.

nking skewed? Is it worth the extra cost?

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You never heard of diversity factor? If you had 20Kw of electrical appliances turned on the house would be uninhabitable in a couple of hours.
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On Sat, 25 May 2013 11:24:04 -0700 (PDT), harry

TropiCal) puts out 112,000 BTUs (40 amps/5.8 KW). I'm thinking that a larger unit that puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and require less time on, thus use, in theory, less electricity - but it's about $500 more expensive than the small

how long it will take to break even on this with running it for only a couple days per week.

Sounds like a leftist plot.
Yet you ask why someone would need more than 100A. Moron!

Idiot. Much of the year, if my "20kW electrical appliances" *AREN'T* turned on, the house would be uninhabitable in a couple of hours.
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On 5/25/2013 11:24 AM, harry wrote:

puts out 112,000 BTUs (40 amps/5.8 KW). I'm thinking that a larger unit that puts out 141,000 BTUs (50 amps/6.4KW), would heat the pool quicker and require less time on, thus use, in theory, less electricity - but it's about $500 more expensive than the small

long it will take to break even on this with running it for only a couple days per week.

location. location. location.
i have an 8kw ceramics kiln, and 10.5 tons of a/c on my house. they frequently are all on at the same time, and my wife can still turn on the stove. i can't imagine being limited to 100a in today's day and age, and would never buy a house that didn't have at least 200a. my next house will probably have at least 300a.
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On Fri, 24 May 2013 23:17:08 -0700 (PDT), harry
11 WK spa heater, 15KW of residential heat, 5.5kw water heater, 8kw range, 4.8 kw electric dryer and then you have your other loads.
It adds up pretty fast.
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On May 25, 3:35 pm, snipped-for-privacy@aol.com wrote:

We have gas for all heating loads in 99% of homes. All of the above would be gas fired here.
No-one uses electricity for heating unless there is absolutely no other option. And then is would be night time electricity on a cheaper rate. Even then it would be more expensive than gas.
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What you have or don't have has no impact on what the rest of the world, like the USA. You already told us that England is soscrewed up that you can't get more than a 100A service unless you go to three phase. Not that I'm buying that, but if it's true, it really is a screwy place indeed.

Yawn.... The same tired canard. "Electricity" for heating implies ordinary resistance heating. "Heat pumps" are what is being discussed here.
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