Heat Pump Water Heaters

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vince

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#106805 31-Jul-2012 21:27

Hi all,

Does anyone here have a Heat Pump Water Heater ?
Looking for advice on split-type units, and efficiency during winter and summer months.
Hoping especially to hear from people in Christchurch.

The ones reviewed in consumer org are 3 years old, and there's only 1 split type
http://www.consumer.org.nz/reports/heat-pump-water-heaters

There was a 10-unit trial of Exceed-branded units in Burnham Military Camp but i can't seem to find the actual result.
http://www.eeca.govt.nz/node/5960

Thanks !

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#665097 1-Aug-2012 06:10

Their cost in NZ is a bit high, not worth the power saving. Years ago there was a very nice model on TradeMe but it was taken off. I suspect it did not have local approval. But was a very nice unit for half the price of the subsidised retail units.

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langers1972

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#665102 1-Aug-2012 06:51

Niel: Their cost in NZ is a bit high, not worth the power saving. Years ago there was a very nice model on TradeMe but it was taken off. I suspect it did not have local approval. But was a very nice unit for half the price of the subsidised retail units.

Of course they're 'worth' the power saving because they're more efficient to run albeit with a higher up front cost.

It seems to be the Kiwi way to only do something if there's something in it for them. Why can't people see the bigger picture in that if we all do something to reduce consumption then in the end we ALL benefit.

Note this isn't a personal attack but a vent of frustration at the general apathy here in terms of efficiency.

timmmay

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#665111 1-Aug-2012 07:36

There's efficiency with money as well as with energy. According to consumer the payback period is too long to bother with unless you use a lot of hot water, and it takes resources to build them too.

I expect them to be more worthwhile in a few years, but not yet, they're still new in NZ.

langers1972

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#665121 1-Aug-2012 08:10

It's this obsession with payback period that stagnates the kiwi building industry, that's why you're only just starting to use double glazing (and even then only because the building code has been changed). Everyone uses pink batts even though you can get products that have double the r value but still fitting in the standard 90mm framing.

Until more people commit to helping the majority instead of the rather selfish 'what's in it for me' approach these superior products will remain out of reach for the majority as greater demand equals lower prices.

Jaxson

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#665122 1-Aug-2012 08:17

I think enforcement is the only way you're going to see this situation change. Fundamentally, it's bad business practise to purchase equipment that costs far more up front than you're ever going to save by using it. That additional money could be in a bank earning interest for the life of the product instead of being sunk into a low energy device that's not really low energy enough.

Like it or not, that's the society we live in. There's low cost and low energy consumption, and they're not the necessarily the same thing. Heat pumps are the flavour of the day, but they do have downsides that don't appear to be acknowledged enough currently. There are concerns regarding defrost cycle frequency in temperate winter locations, and the power factor/back effect on the supply grid by using more Aircon units etc.

If we as a society did chose to value low energy consumption (which we should, as this reduces the need for more power stations, not all of which are 'nice' on the environment) then we need some form of enforcement or incentive scheme to promote the use of these devices. Just to be clear, I'm all for this, as I think we trade on the 'Clean and Green' banner despite not doing enough to ensure that is sustainable. I feel we're clean and green due to our location and not yet stuffing it up, rather than much we're actively doing to ensure this situation continues.

timmmay

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#665125 1-Aug-2012 08:23

langers1972: It's this obsession with payback period that stagnates the kiwi building industry, that's why you're only just starting to use double glazing (and even then only because the building code has been changed). Everyone uses pink batts even though you can get products that have double the r value but still fitting in the standard 90mm framing.

Until more people commit to helping the majority instead of the rather selfish 'what's in it for me' approach these superior products will remain out of reach for the majority as greater demand equals lower prices.

I agree, to a point. Insulation and double glazing have huge benefits, save a lot of energy and reduce condensation making a home more liveable, and aren't that much more expensive than single glazing or no insulation. When something has more costs than benefits though I would tend to disagree.

Which insulation has double the R value of pink batts?

You could always move to a socialist country...

langers1972

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#665160 1-Aug-2012 09:00

timmmay: Which insulation has double the R value of pink batts?

PIR board which is basic standard in most of Europe, see http://www.celotex.co.uk/products/celotex-products/celotex-ga4000 Can get it here for $52/sqm which is double R2.8 batts but it's twice as effective and ought to be the go to product here.

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kiwitrc

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#665169 1-Aug-2012 09:13

langers1972:
timmmay: Which insulation has double the R value of pink batts?

PIR board which is basic standard in most of Europe, see http://www.celotex.co.uk/products/celotex-products/celotex-ga4000 Can get it here for $52/sqm which is double R2.8 batts but it's twice as effective and ought to be the go to product here.

Good grief I have to fill out my life history to get a F#$king data sheet. Looks like a great product though as I guess it wont compress like pink batts either. I hate pink batts.

langers1972

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#665177 1-Aug-2012 09:25

Poor formatting but this gives you an idea (I can't attach the PDF)

Product Code Thickness (mm) R-value (m?K/W) Weight (kg/m?)
GA4050 50 2.25 1.55
GA4055 55 2.50 1.74
GA4060 60 2.70 1.90
GA4065 65 2.95 2.05
GA4070 70 3.15 2.19
GA4075 75 3.40 2.34
GA4080 80 3.60 2.48
GA4085 85 3.85 2.62
GA4090 90 4.05 2.76
GA4095 95 4.30 2.90
GA4100 100 4.50 3.27

These guys import it into NZ and are very knowledgeable http://www.composite-nz.co.nz/dynamicpage.asp?pageid=1

Jaxson

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#665194 1-Aug-2012 09:37

kiwitrc: . I hate pink batts.

Especially the blown approach.

I had blown rockwool and blown pink batts in my roof, and they had all subsequently been blown to one end of the roof. 30cm deep over one end of my lounge and bare gib board ceiling over the wind facing rooms....

timmmay

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#665198 1-Aug-2012 09:40

Why's there so much wind in your ceiling?

Jaxson

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#665201 1-Aug-2012 09:46

timmmay: Why's there so much wind in your ceiling?

Ha, true! I suspect the bulk of that thickness was from the actual install process but definitely it was thinner towards the wind facing side of the house. Natural leaks I guess, coupled with the standard roof vents. In addition there were some very unfortunate bracing beams near that same wind facing side which would have prevented the insulation from being able to be blown into that area as well.

I quite like the wide blanket approach, it's supposed to result in a better overall 'system' r value than laying the same r value insulation down between the ceiling beams. Must be a nightmare to work in the ceilings afterwards though, as you'd not be able to see the beams/cables underneath any more.

Sorry, none of this relates to heat pump hot water heaters.

chiefie

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#665214 1-Aug-2012 10:05

We have it. And works brilliantly well. This is our model: http://www.rheem.co.nz/heat-pump-water-heaters/product/A551310/

We have the single unit one - saved us some indoor space by putting the water tank and the heating unit outside. It worked well through the 2011 and 2012 snow storms. We installed it back in later 2010.

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timmmay

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#665248 1-Aug-2012 10:48

Did your power bill drop significantly when you got it chiefie?

chiefie

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#665258 1-Aug-2012 10:57

timmmay: Did your power bill drop significantly when you got it chiefie?

Seems to have, but then we don't actually actively "conserve" the power usage. We're with Powershop as well but this year, we haven't "stock up" for winter.

Regardless, we enjoy having the HPWH as it heats up water quicker and seems to have unlimited hot water for 4 people, twice a day shower and hot water dish washing. The heating cycles happen throughout the day when the temperature is below a certain threshold and it spins up and heat for short period then spin down.

It takes a bit to get use with a very low rumbling noise - as with any heat pump - soon slowly it just become ambient noise that you won't notice so much of. We didn't have any heat pump unit so it was pretty obvious to us at the very start.

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