I read somewhere (consumer?) that unless you use a lot of hot water the payback period may not make sense, given the high initial costs.

timmmay:

 

I read somewhere (consumer?) that unless you use a lot of hot water the payback period may not make sense, given the high initial costs.

 

That's just saying that it's much the same situation as heat pump heating. Most people don't get heat pumps based on payback because it is common for heat pump users to use more heating so their power bills don't actually go down. I think that hot water use would also increase but probably not to the same extent.

As hot water heating is the largest power cost for the large majority of households, we also have the biggest opportunity to benefit from the efficiency of heat pumps.

I think space heating heat pumps tend to be used because of their high output and low running costs, and yes power bills probably go up along with comfort factors. Hot water is 1/3 of the bill, home heating is probably similar or even more in winter, so heat pumps make more sense. For a couple with no kids who shower daily, with a well insulated cylinder, there may be no gain. For a 5 person household with teenagers or people who take lots of baths there's probably a big gain. Combine it with Flick electric and try to defer some of the heating until 3am and you'd get a double whammy.

I didn't consider a heat pump water heater when we replaced our cylinder a couple of years back, mostly because we don't use that much water, but also because we don't really have anywhere we can put an outdoor cylinder. Do they do split systems yet?

timmmay:

 

I read somewhere (consumer?) that unless you use a lot of hot water the payback period may not make sense, given the high initial costs.

 

When I did the numbers - it was better pay back than solar so far the savings have been quite significant on our power bill so its paying itself off faster than I calculated but definitely right given the cost not something that you want to invest in for the short term.

timmmay:

 

I think space heating heat pumps tend to be used because of their high output and low running costs, and yes power bills probably go up along with comfort factors. Hot water is 1/3 of the bill, home heating is probably similar or even more in winter, so heat pumps make more sense. For a couple with no kids who shower daily, with a well insulated cylinder, there may be no gain. For a 5 person household with teenagers or people who take lots of baths there's probably a big gain. Combine it with Flick electric and try to defer some of the heating until 3am and you'd get a double whammy.

 

I didn't consider a heat pump water heater when we replaced our cylinder a couple of years back, mostly because we don't use that much water, but also because we don't really have anywhere we can put an outdoor cylinder. Do they do split systems yet?

 

Seems most of the quotes I had were for split systems.  When I went into it I wanted an integrated system to be honest but now like the fact its split - also it being split gives redundancy if the hotwater heatpump ever plays up I can just switch on the heating element on the normal hot water cylinder and use that till I get the heatpump looked into.

You can also use hot water for underfloor heating which bolsters the economic case.

Underfloor heating is the main source of split systems for heating water in NZ.

rphenix: When I did the numbers - it was better pay back than solar so far the savings have been quite significant on our power bill so its paying itself off faster than I calculated but definitely right given the cost not something that you want to invest in for the short term.

 

Yeah I bet it's better than solar, solar is still a super long payback time. A friend spent $14K on solar, his savings are only a little more than I saved moving to Flick.

while 510mm may be an odd size they actually do larger cylinders that are smaller in diameter. you can get a 177L one thats 480mm in diameter

Kickinbac: I have an old 80's 135 litre hot water cylinder. It warms our hot water cupboard well so know its leaking heat so needs replacing. The cylinder can't be wrapped as its too tight in the cupboard. It's an odd size (510mm) so can't fit a larger cylinder for the extra storage required for split hot water heat pump or solar. Which leaves me looking at an external cylinder with heat pump.

Can you not put a cylinder under the roof? Having the cylinders inside significantly reduces heat losses.

You can get custom made low-pressure cylinders - not sure about mains pressure cylinders. Is there space to fit a taller cylinder in the same cupboard? One issue with doing this is that solar has additional water pipes which need space too.

If you went solar then it is worthwhile having two cylinders with solar used for preheating a larger tank to feed the tank you draw the hot water from.

I put my hot water cylinder up in the ceiling cavity, which is huge in this old house. We went from low to high pressure at the time. I put a wrap around it because I had one lying around, but it doesn't get that warm under the wrap. It works well and freed up heaps of cupboard space.

We are getting a HWHP installed in our new home. We haven't confirmed which one yet though. We were originally going with the Bosch AIO, but decided it was fugly. So we are going with a split unit. Either the Econergy or Exceed.

When we renovated our place, we took out the hot water cylinder and installed an outdoor hot water heat pump. It's great... We gained some space back inside the house, we don't use the main water reservoir in roof and we have hot water most the time.

chiefie:

 

When we renovated our place, we took out the hot water cylinder and installed an outdoor hot water heat pump. It's great... We gained some space back inside the house, we don't use the main water reservoir in roof and we have hot water most the time.

 

"Most of the time"?