Looking for a new pool heat pump - anyone know anything about them?

Forums › Home Workshop DIY › Looking for a new pool heat pump - anyone know anything about them?

davecla

61 posts

Master Geek

#317857 21-Nov-2024 13:23

My old pool heat pump has packed up and I've been instructed to get it sorted for this summer.

The old one is 20-odd years old, so not worth repairing, so I'm looking for a replacement.

Current one is rated 28kW, I'll need to replace it with something that size.

I've spend a few hours online looking at what's around, there seems to be a huge number of brands I've never heard of, even some of the "names" some look to be direct Chinese imports with an ANZ skin.

Hayward is supposed to be a well known brand, but their installation manual is obviously translated from Chinese (as some characters remain), these may be great heaters, but worth twice as much as a lesser known brand? - Sunrain for example are half the price, but arn't fronted by a pool company.

I was hoping to spend circa $10k on a new one, but have seen pricing ranging from $8k to $20k (supply only).

I cant tell if this is just massive markup, or if there is significant difference between brands.

Hoping someone here can provide insight, or advise which are the good ones

Cheers

dave

(I've looked at solar in the past, wont work for me here)

dimsim

848 posts

Ultimate Geek

Trusted

Lifetime subscriber

#3311447 21-Nov-2024 14:30

Here's what our pool company quoted us for heating.

$8,670 inc gst - Hot Water Heat Pump Model 7GP11-1 fitted on concrete pad outside pump shed and plumbed in-line. Suit 28°C Oct to April, 2.2kW in, 11kW out

Which I assume is this

They are an established company so suspect it would have been of reasonable quality.

We didn't go ahead with it however as we're only interested in using the pool in summer when it's hot.

EDIT: for reference, the pool is 55k litres and approx 10mx5m

Jase2985

13457 posts

Uber Geek

ID Verified

Lifetime subscriber

#3311448 21-Nov-2024 14:33

Need some more info,

what size pool?(L)
what temperature do you heat to?
what swimming season are you hoping for?
what size power feed do you currently have to the existing heatpump?
do you know the model of the current one?

You may not need as big as you think, as things have gotten more efficient over time.

davecla

61 posts

Master Geek

#3311453 21-Nov-2024 14:41

Jase2985:

Need some more info,

what size pool?(L)
what temperature do you heat to?
what swimming season are you hoping for?
what size power feed do you currently have to the existing heatpump?
do you know the model of the current one?
You may not need as big as you think, as things have gotten more efficient over time.

Hi,

70k litres

26 degrees I guess, warm enough to be pleasant, but not a bath, I'm in Wellington

Mid December - March

Single 1 phase, 40 amp circuit to pool submain

Hot water heat pump HW275

I've got one of the blue bubbly covers, but not a proper thermal blanket

Thanks

HowickDota

423 posts

Ultimate Geek

#3311454 21-Nov-2024 14:41

dimsim:

Here's what our pool company quoted us for heating.

$8,670 inc gst - Hot Water Heat Pump Model 7GP11-1 fitted on concrete pad outside pump shed and plumbed in-line. Suit 28°C Oct to April, 2.2kW in, 11kW out

Which I assume is this

They are an established company so suspect it would have been of reasonable quality.

We didn't go ahead with it however as we're only interested in using the pool in summer when it's hot.

EDIT: for reference, the pool is 55k litres and approx 10mx5m

I mainly work on regular heat pumps but have serviced this model before and it is based off a Temperzone condenser unit which is made in New Zealand with quality and easily serviceable parts. Temperzone also have their own range of magnus pool water heat pumps which might be worth looking into.

Jase2985

13457 posts

Uber Geek

ID Verified

Lifetime subscriber

#3311456 21-Nov-2024 14:53

dimsim:

Here's what our pool company quoted us for heating.

$8,670 inc gst - Hot Water Heat Pump Model 7GP11-1 fitted on concrete pad outside pump shed and plumbed in-line. Suit 28°C Oct to April, 2.2kW in, 11kW out

Which I assume is this

They are an established company so suspect it would have been of reasonable quality.

We didn't go ahead with it however as we're only interested in using the pool in summer when it's hot.

EDIT: for reference, the pool is 55k litres and approx 10mx5m

I have a Hot Water Heat Pump THP12-1 which is similar to what you have posted. Been running it for 3 years now, and we usually get mid-October to ANZAC day out of the pool. Takes about 4-6 days to initially heat it, and at the moment it's taking about 6-7h to keep at temp during the day, In Dec-Feb its hardly on at all. With the pump and heat pump, It's using about 2.8kW/h.

Jase2985

13457 posts

Uber Geek

ID Verified

Lifetime subscriber

#3311460 21-Nov-2024 15:02

davecla:

Jase2985:

Need some more info,

what size pool?(L)
what temperature do you heat to?
what swimming season are you hoping for?
what size power feed do you currently have to the existing heatpump?
do you know the model of the current one?
You may not need as big as you think, as things have gotten more efficient over time.

Hi,

70k litres

26 degrees I guess, warm enough to be pleasant, but not a bath, I'm in Wellington

Mid December - March

Single 1 phase, 40 amp circuit to pool submain

Hot water heat pump HW275

I've got one of the blue bubbly covers, but not a proper thermal blanket

Thanks

Hot Water Heat Pumps LTD rate their heat pumps by surface area, so given your pool is about double mine, I would say ~70m2?

Even something like the 7GP20-1 is rated for Central North Island/South Island residential Surface Area 80m2, for mid-October to mid-April and will easily do 26 degrees. It is single phase 32amp breaker, and would be using about 16 amps when running.

If you wanted to swim for a longer season, I would recommend getting a thermal cover, it really does help keep the heat in.

davecla

61 posts

Master Geek

#3327596 5-Jan-2025 08:02

New HP installed and warm pool = happy wife!

I ended up getting another one from Hot Water Heat Pumps.

My old one was labeled HW275, which I'd assumed meant it was a 27.5kW model, but actually referred to 2.75kW of input power. With an average CoP of just over 4, the manufacturer reckoned it was about 14kW output.

The new one is only slightly larger, about 17kW rated output. It seems to do the job ok, even though this summer in Wellington we are looking at highs of 13 - 14 degrees. It needs to run for 12 - 14 hours a day to keep the temperature at a pleasant 28 degrees.

Interesting convo with the HWHP guys about why they don't use inverter technology in their HP's (because of the huge thermal mass of the water there is no value in it)

It was also interesting to hear that the rated output power is mostly just made up based on best case CoP values, so those numbers are often just marketing fluff.

One things with the HWHP's that was initially a selling point for me, but I now sort of regret is their very basic controller.

It has a simple flow switch, if the water is flowing and it's not up to temp, the HP runs. This means once it's up to temperature, the filter continues to run because it knows, no better.

Other brands have a more complex system (from what I could tell from the brochures) where the HP controls the filter operation via a contactor.

Anyways, I figure I can do better, so I'm going to have a crack at automating it.

Dave

Equinox IT

Cloud spending continues to surge globally, but most organisations haven’t made the changes necessary to maximise the value and cost-efficiency benefits of their cloud investments. Download the whitepaper From Overspend to Advantage now.

tweake

2391 posts

Uber Geek

#3327667 5-Jan-2025 11:08

davecla:

Interesting convo with the HWHP guys about why they don't use inverter technology in their HP's (because of the huge thermal mass of the water there is no value in it)

interesting comment.

i think there answer is over simplified. i would guess its because the units are quite small for the load, the loads don't change a lot and have long run times already. also single stage is the cheapest to make, more value in the profit margin.

variable would still be better, as they can slow down to match the losses and they are more efficient when running slower.

it would be interesting to see what your run times are.

Jase2985

13457 posts

Uber Geek

ID Verified

Lifetime subscriber

#3327842 5-Jan-2025 15:22

tweake:

davecla:

Interesting convo with the HWHP guys about why they don't use inverter technology in their HP's (because of the huge thermal mass of the water there is no value in it)

interesting comment.

i think there answer is over simplified. i would guess its because the units are quite small for the load, the loads don't change a lot and have long run times already. also single stage is the cheapest to make, more value in the profit margin.

variable would still be better, as they can slow down to match the losses and they are more efficient when running slower.

it would be interesting to see what your run times are.

i think you are overanalyzing things there. Most pools are 20,000L or more with a massive thermal load/capacity. They are not hot water cylinders or houses. It would offer very little benefits.

You don't want/need your pool pump running all day/night, that's using power, .75kw or more per hour. When the pump is running, it's generally using chemicals, which is another cost if you don't have a different way of managing that.

It's just easier/more efficient to heat the water as fast as possible, than try to maintain it there, you won't notice the difference between 28 and 27.5 degrees. it also takes about 28kw/h of energy to heat 20,000L from 27–28 degrees, not withstanding any losses. thats a couple of hours with a modest sized heatpump.

My pool looses less than a degree from 1600-1100 the following day (summer night temps, not the 13-14 degrees we have been seeing recently) and takes 2-3h a day to recover, to doesn't need a variable speed heat pump to maintain it given the pump is going to be off overnight. If it looses .3 degrees before the pump turns off for the day, you wouldn't notice that.

tweake

2391 posts

Uber Geek

#3327858 5-Jan-2025 16:06

Jase2985:

i think you are overanalyzing things there. Most pools are 20,000L or more with a massive thermal load/capacity. They are not hot water cylinders or houses. It would offer very little benefits.

You don't want/need your pool pump running all day/night, that's using power, .75kw or more per hour. When the pump is running, it's generally using chemicals, which is another cost if you don't have a different way of managing that.

It's just easier/more efficient to heat the water as fast as possible, than try to maintain it there, you won't notice the difference between 28 and 27.5 degrees. it also takes about 28kw/h of energy to heat 20,000L from 27–28 degrees, not withstanding any losses. thats a couple of hours with a modest sized heatpump.

My pool looses less than a degree from 1600-1100 the following day (summer night temps, not the 13-14 degrees we have been seeing recently) and takes 2-3h a day to recover, to doesn't need a variable speed heat pump to maintain it given the pump is going to be off overnight. If it looses .3 degrees before the pump turns off for the day, you wouldn't notice that.

there is a some incorrect statements in that.

they are effectively hot water cylinders or houses. its the exact same job. heat up to a temp. hot water cyl has mass. houses have mass. the amount is different but the operation is the same.

reheating it back up after letting it go cold is actual LESS efficient. heating it up as fast as possible is LESS efficient. a variable heat pump maintaining temp operates more efficient than it does at full speed reheating. the efficiency specs for them are for partial speed not full speed. just like in good homes, heat pumps work best and most efficiently when they are constantly running. (the problem there is most kiwis don't have good homes)

the pool pump, thats quite correct. but there are ways around that.

you mention taking 2-3 hrs to recover temp, with a variable that would be maybe 5-6 hours but with less energy used. with the amount of power used that can be a decent saving in power cost, especially given i saw a few variable heat pump pool units for about the same price as a single stage.

the main thing is how its used. if people turn the system off over night etc (eg for noise reasons), then that tends to make variables less useful.

Jase2985

13457 posts

Uber Geek

ID Verified

Lifetime subscriber

#3327866 5-Jan-2025 17:16

tweake:

Jase2985:

i think you are overanalyzing things there. Most pools are 20,000L or more with a massive thermal load/capacity. They are not hot water cylinders or houses. It would offer very little benefits.

You don't want/need your pool pump running all day/night, that's using power, .75kw or more per hour. When the pump is running, it's generally using chemicals, which is another cost if you don't have a different way of managing that.

It's just easier/more efficient to heat the water as fast as possible, than try to maintain it there, you won't notice the difference between 28 and 27.5 degrees. it also takes about 28kw/h of energy to heat 20,000L from 27–28 degrees, not withstanding any losses. thats a couple of hours with a modest sized heatpump.

My pool looses less than a degree from 1600-1100 the following day (summer night temps, not the 13-14 degrees we have been seeing recently) and takes 2-3h a day to recover, to doesn't need a variable speed heat pump to maintain it given the pump is going to be off overnight. If it looses .3 degrees before the pump turns off for the day, you wouldn't notice that.

there is a some incorrect statements in that.

they are effectively hot water cylinders or houses. its the exact same job. heat up to a temp. hot water cyl has mass. houses have mass. the amount is different but the operation is the same.

reheating it back up after letting it go cold is actual LESS efficient. heating it up as fast as possible is LESS efficient. a variable heat pump maintaining temp operates more efficient than it does at full speed reheating. the efficiency specs for them are for partial speed not full speed. just like in good homes, heat pumps work best and most efficiently when they are constantly running. (the problem there is most kiwis don't have good homes)

the pool pump, thats quite correct. but there are ways around that.

you mention taking 2-3 hrs to recover temp, with a variable that would be maybe 5-6 hours but with less energy used. with the amount of power used that can be a decent saving in power cost, especially given i saw a few variable heat pump pool units for about the same price as a single stage.

the main thing is how its used. if people turn the system off over night etc (eg for noise reasons), then that tends to make variables less useful.

Most people turn them off overnight as, 1, its noisy, 2, it uses more power and 3, it uses more chemicals.

A house, a hot water cylinder and a swimming pool, while all requiring heating, have a massive difference in the thermal mass and energy contained in them. That is why a pool doesn't really need s variable speed heat pump because it takes so long to cool down and you don't feel the difference. Bit different with a hot water cylinder or your house. You notice the difference straight away when the heat pump stops, unless you're in an ultra efficient house. Hot water it doesn't take long to feel the difference in the hot tap on a smaller hot water cylinder.

They really aren't needed in pools due to the way people use them, and the other things that go along with using the heat pump, which has been mentioned before.

dimsim

848 posts

Ultimate Geek

Trusted

Lifetime subscriber

#3327893 5-Jan-2025 18:43

i love this place, fantastic insights and discussions.

@davecla - what is the make/model of your new pump, what was the approx cost and what are the other "smarter" options you are aware of.

As @Jase2985 mentions above, and as a pool owner (specifically with a salt-water chlorinator or UV etc), we only want/need the pump to run for a specific amount of time, given the volume and conditions, to keep the water sanitised and filtered and also to reduce noise. my thoughts regarding how heating operates is that if the pool doesn't meet a particular setting during it's standard daily filtering cycles then it heats or doesn't heat. Possibly if it requires longer to reach a set temperature, the filter/heating cycle is extended.

If it's only taking 3-4 hours of heating to maintain a temp then that would be within my two daily filtering cycles so would this be how a simple or more complex system works?

tweake

2391 posts

Uber Geek

#3327901 5-Jan-2025 19:19

Jase2985:

Most people turn them off overnight as, 1, its noisy, 2, it uses more power and 3, it uses more chemicals.

A house, a hot water cylinder and a swimming pool, while all requiring heating, have a massive difference in the thermal mass and energy contained in them. That is why a pool doesn't really need s variable speed heat pump because it takes so long to cool down and you don't feel the difference. Bit different with a hot water cylinder or your house. You notice the difference straight away when the heat pump stops, unless you're in an ultra efficient house. Hot water it doesn't take long to feel the difference in the hot tap on a smaller hot water cylinder.

They really aren't needed in pools due to the way people use them, and the other things that go along with using the heat pump, which has been mentioned before.

fair enough

tho that makes me wonder what the programming is like and what split they run. a house heatpump is often around 2-3 degrees before setpoint where it starts dropping speed. thats its most efficient usage range where you don't notice much difference but its rolled back the speed and gains efficiency.

"You notice the difference straight away when the heat pump stops, unless you're in an ultra efficient house." thats actually not true. sorry i'm a home performance fanboy and that drives me nuts. the reason you notice the difference when it stops is because the house is not heated up. a properly insulated (but not ultra efficient) house can be heated up properly. however the cause of that is because "due to the way people use them". people turn off the heat pump to save costs due to the house being badly insulated (most kiwi homes). thats kinda where we get the misinformation that turning off heat pumps is "more efficient".