Advice wanted re Heat Pumps

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madcarue

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#227446 7-Jan-2018 16:46

Please can anyone give advice on heat pumps, I live on the central plateau and my trusty old night store and wood burner are in a state of repair and being 25+ years old parts are not available, so I am looking at installing a heat pump but will keep the log burner in place in case of power cuts or failure of heat pump to do its job.

Size required varies from 8.2 Kw high wall mtg recommended by Mitsubishi to a general recommendation of 10-12 Kw.

Room size 10x5x2.72m. Ceilings insulated and say 30% of walls are insulated, large bay windows with thermo drapes.

We get a fair few frosts and a few mornings down to – 5deg C.

I was going for a Daiken but have been told that Mitsubishi are just as good and a bit cheaper, price is not the main concern I want performance and reliability and I do need a quite one.

Assuming a morning start of say 6:30 is it best to leave the heater on all night at say 10 deg C as opposed to leaving off over night and setting to come on at 6am at 20deg C.

Thank you.

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#1931773 7-Jan-2018 16:52

Daikin all the way.

I put in a 6kw Panasonic last year and regret not grabbing the Daikin.

vexxxboy

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#1931800 7-Jan-2018 18:08

i would go for the hypercore Mitsubishi with wifi, i have one and they do what they say they do and are also very quiet. You are just wasting power if you leave them on all night if you have good instalation, i set mine to come on 40 minutes before i get up and the house is nice and warm

Common sense is not as common as you think.

Aredwood

3885 posts

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#1931801 7-Jan-2018 18:10

Are you in the TLC lines company area? If so then getting a heatpump would probably increase your lines fees.

If so, consider putting the heatpump on ripple control, and use the fire while the load management is active.

Although if you have electric cooking. Change that to gas. As that would be a bigger reduction in peak demand fees, for only a small amount of gas usage. And you will still be able to cook during powercuts.

Jase2985

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#1931808 7-Jan-2018 19:16

you cant set the heatpump to 10 degrees, most go down to 16-18 as a minimum. its likely cheaper to turn it off at night if the room is unused and turn it on about 30 mins before you get up or get home

timmmay

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#1931820 7-Jan-2018 20:09

If your house gets down to 10 degrees at night you should look at insulation first. A heat pump would hugely increase your bills.

Last year when my wife was home all day we left the heat pump on 5am - 10pm, getting up around 6am. The house felt quite a bit warmer than when we turned it on and off as needed. Even if no-one was here I'd consider keeping it turned on 18 degrees during the day in the depths of winter, then increasing to 21 / 22 just before we need it.

WiFi control from phone would be good, with a decent time that you can do multiple changes per day. My older Daikin works well. The Fujitsu Nocria I have is quite loud, I wouldn't get another. I use a small Broadlink device I got from ebay to control my older heat pumps from my phone.

Batman

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#1931844 7-Jan-2018 20:37

Daikin or Mitsubishi are good.

Always over spec than under spec, you will regret if it's not powerful enough.

And, cheaper than renovating the house.

reven

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#1931877 7-Jan-2018 21:20

my old house (about 150m2, 2.4metre walls) was all powered by a single 11.2kw system... 10kw for one room, seems over kill.

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Sideface

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#1931879 7-Jan-2018 21:34

Batman:

Daikin or Mitsubishi are good.

Always over spec than under spec, you will regret if it's not powerful enough.

And, cheaper than renovating the house.

As above.

Always overspec.

Daiken & Mitsubishi are both excellent - I love the almost complete silence of two Mitsi heat pumps in our Wellington house.

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Geektastic

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#1931881 7-Jan-2018 21:43

Friends down south swear by Daikin claiming better efficiency when the outside temperatures get very low. We have Fujitsu (4) and they do ice up around 5 C and then have to defrost.

We run ours almost every day, cooling or heating, but not overnight in winter unless it's really really chilly.

Technofreak

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#1931884 7-Jan-2018 22:04

We put in a 6 Kw Fujitsu ABTG18LVTA floor console at the start of last winter. We are very happy with it.

We have cathedral ceilings and a lot of window area (floor to ceiling) and due to the catherdral ceilings the windows have no drapes at the top. Downstairs is open plan with no way to stop the heat going upstairs though we can shut the door upstairs. So it's heating well over 50 sqr metres with minimal insulation and high ceilings.

Other than a couple of very cold foggy mornings it never had to stop to defrost and when it did it was for only 15 minutes or so. Prior to this year the inside temperature would go as low as 5 degrees over night as we were only using a oil column heater while we were up and about.

I'd really recommend a floor mount as I think a floor mounted heat pump is more effective for heating.

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richms

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#1931892 7-Jan-2018 22:37

Disagree about the overspecing of them. The inverters will go down to about 10% of the max output from what I have been told. This means when requirements are minimal like a 28 degree outside day in summer or about 16 in winter, that the min output is more than is needed and they will cycle off and on completely, with the noise that brings. I have to have the fan set to low on my bedroom one otherwise it ramps it down and up all the time when the needed output is minimal. Thats with a 3.5 or 3.7kw one in a 11m2 room

Richard rich.ms

Goosey

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#1931922 8-Jan-2018 07:13

Given your location, you need somthing that will have an outdoor operate without a flinch in the winter i.e. run more than happy at -5 for hours.

Technofreak

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#1931926 8-Jan-2018 07:41

richms:

Disagree about the overspecing of them. The inverters will go down to about 10% of the max output from what I have been told. This means when requirements are minimal like a 28 degree outside day in summer or about 16 in winter, that the min output is more than is needed and they will cycle off and on completely, with the noise that brings. I have to have the fan set to low on my bedroom one otherwise it ramps it down and up all the time when the needed output is minimal. Thats with a 3.5 or 3.7kw one in a 11m2 room

That's probably the case if it's really over sized. However it's still way better to be slightly over then be undersized and have the unit struggling all the time and needing constant defrosting. Because then you use a lot of energy and don't get much heat.

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timmmay

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#1931931 8-Jan-2018 08:13

reven:

my old house (about 150m2, 2.4metre walls) was all powered by a single 11.2kw system... 10kw for one room, seems over kill.

I have one Fujitsu Nocria around 10kw or a bit more heating approx 100 square meters of old but well insulated house. I wouldn't want any smaller. Once the house is up to heat it does spend a fair amount of time off now that we're fully insulated and double glazed.

Technofreak:

I'd really recommend a floor mount as I think a floor mounted heat pump is more effective for heating.

If you have space I think they're probably better, and quieter, and less ugly.

madcarue

86 posts

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#1932254 8-Jan-2018 14:59

Thanks to all that responded you have provided a lot to think over and any more info is very welcome, Thanks.

@Aredwood yes I am with TLC and with their new TOU system about to kick in you can guarantee it will be more expensive I emailed them and await an answer

@Vexxxboy I have heard about hypercore but not sure what it is and yes will go for wifi

@Reven Point taken

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