New House: Should We Do Heatpump HWC or Panel Type or Traditional? Also - Indoor HWC Vs Outdoor HWC

mickey9876 on 02/10/2024 - 12:41

Building new house in Chch so winter power usage can get fairly high and hot water cylinder is the major power hog.
Also, trying not to go too over board as this might be our home for about 4-6 years and then probably will move to Nelson or somewhere warmer for work so this house we may be forced to rent it out depending on the market or sell.

Options currently that we are toying with:
1. Heatpump hot water cylinder (expensive-ish but most efficient apparently and will be outdoor, so added bonus of saving indoor storage space)
2. Panel type ones (not solar because apparently solar is heavily outdated now but new panel type: cons will be super expensive)
3. Traditional HWC - cheaper install cost but more expensive to run. Best option if we decide to move in the short term.

General Discussion

Comments

  • Wakrak on 02/10/2024 - 12:53

    Might be worth posting on Geekzone too

    • mickey9876 on 02/10/2024 - 15:04

      I'll do a search first and see if there is already something there before posting!

  • FiveFeetUnder on 02/10/2024 - 13:47

    Heat Pump hot water won't pay for itself with savings over 5yrs (due to the much higher price), more like 8-10yrs when I last looked.

    We ended up going for a standard mains pressure electric HWC with dual elements, and then hooked the bottom element up to a timer to run on the Contact 3hrs of Free Power each night from 9-midnight. This saves us 3kwh x 3hrs per night, which is like $700 per year

    • mickey9876 on 02/10/2024 - 15:05

      Interesting as from my limited research, it says HeatPump-HWC saves 50-75% of the traditional HWC cost. And if we assume 30-50% of power costs is from HWC, wouldn't this savings be much higher?

  • tomb98 on 02/10/2024 - 16:48

    The issue with heat pump HWC is that they cost around $7-8k to install vs $1-2k for a traditional. The rated lifespan of them are about the same (10-15 years), though I suspect they can go a lot further. So the question really is if you think you'll save at least $1000 a year in hot water electricity over conventional. Personally, having a heat pump HWC installed myself and going from a traditional HWC, I can say the savings are somewhat exaggerated. I think optimistically, I'm maybe saving about 20% using the heat pump one at most? Also, the heat loss and running cost even if you don't use the cylinder much is quite large. On a 300L cylinder, I use about 10-15kw (at least) per day even with minimal use.

  • mickey9876 on 02/10/2024 - 21:26

    So this page is good but only compares heat pump HWC to gas. I wonder how it compares to traditional HWC- https://genless.govt.nz/for-everyone/at-home/energy-saving-a…

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