Help me choose a heat pump

**normajeane** · 18th April 2009, 22:48

Originally Posted by Scaredy Cat

Thanks for all your help so far.
.

Regarding a breeze in the room with the heat pump going, it doesn't really bother me as longs as its warm air.

Ahhhh, the breeze. Ours is a wall attachment and I thought like you that as long as it is WARM, well during the warm cycles it does blow cool - depending on your set temp. At the mo it is on 19 warm and the flow is curling around my feet from the wall and it is COOL. So, I would recommend a Floor mounted job that does not force itself down around your feet/neck and draught the cool parts over you! Otherwise it is the best thing since sliced bread.

**Max Preload** · 19th April 2009, 00:31

Originally Posted by Winston001

Good calculations which seem pretty accurate, although I understood that maximum efficiency was 1:3 ie. 1kw electricity produces 3kw of heat. When the ambient temperature is close to or below zero, the efficiency is less - just when you use it most.

Their CoP (co-efficient of performance, which is NOT to be confused with efficiency which cannot exceed 100%) varies greatly with the temperature differential between ambient outside and room temperature. The higher that difference, the lower the CoP. Also heat pumps use a little more power at lower temperatures because they're operating closer to dewpoint so have to use energy to defrost the evaporator.

0lddog · 19th April 2009, 01:55

Originally Posted by Max Preload

........... Also heat pumps use a little more power at lower temperatures because they're operating closer to dewpoint so have to use energy to defrost the evaporator............

The COP figure is based on a standard outside temperature ( think its 7C W.B. - but would have to look it up to be sure )

With most heat pumps the COP figure changes significantly as the outside temperature changes. Manufacturers publish graphs of the variation ( at least Mitsi, Daiken and Toshiba do )

As the outside temperatire falls so the COP falls

This is of course a shame as its not untill its very cold outside that you really need inside heat !

**Laxi** · 19th April 2009, 02:12

got a cheap one from te whare about 4 years ago, weve got an old ex housing corp up stairs, down stairs, its in the lounge downstairs and warms the whole upstairs too, never had a problem with it

**munterk6** · 19th April 2009, 14:41

I have an HRV and a 4.5kw Panasonic heatpump. I have insulated the ceiling and underfloor in my 55 year old weatherboard and concrete rooftiled house...90 sqmtrs. The HRV made a real difference to the general humidity and dry air is a lot easier and cheaper to heat than damp air. Its like the heatpump is on steroids now with the HRV doin' its thing.
The temp has never gone below 16 degC and the humidity hovers around 40 to 50%. And this is WITHOUT the heatpump on!
I paid $2600 for the HRV and I reckon my $$$ were well spent..I'm happy.
The heatpump was s/h and was $1600 installed. Never had a problem with it after 2 years. In case of power outage, I have retained the chip burner in the kitchen.

**Disco Dan** · 19th April 2009, 15:23

Anyone seen the mitsubishi heat pump advert? The one with the 'thermal camera' ?

The one that shows all the colours - the heat around the room ?

The one that shows a COLD BLOODED GOLDFISH in a COLD WATER tank as HOT?

Cracked me up when i saw it... sad that people will actually believe them.

**Trouser** · 19th April 2009, 15:40

That has probably been in that room soaking up the heat so it is now ambient. Do you think people refrigerate goldfish tanks then?

**Disco Dan** · 19th April 2009, 16:06

Originally Posted by Trouser

That has probably been in that room soaking up the heat so it is now ambient. Do you think people refrigerate goldfish tanks then?

A cold blooded fish remains the same temperature as the water it is in.

The advert showed the fish as red while the water stayed 'white'. Indicating that the fish was just as hot as a human being.

Obviously impossible.

**Ocean1** · 21st April 2009, 19:06

Originally Posted by davereid

Do they save much money ?
If your heat pump cost $4000 installed, you will break even after 13.3 years.

Or more, as you say.

Other advantages they've got are the timer function and the quiet(er) fan circulation.

So, are there any direct electric heaters in the upper size range out there that, (while costing twice as much to run) match those features?

**eldog** · 23rd July 2016, 19:49

Ok, looking at getting a heat pump system(s)

getting either Daiken or Mitsi system

So far had 2 people look at house (don't think I need more, unless someone knows otherwise)

Waiting for the Mitsi quote...... The guy is well know local business.

Both seem to do/look at the same system ideas.

Currently the Daiken one is offering 2 off split systems (1x2 areas and 1x3)with a energy recovering unit as I asked if we could also add some outside air to the rooms-also to help air flow. I can use the air from the roof for heat exchange but don't want to use it as part of incoming air because of musty smell from rodents etc. so HRV and DVS are currently off the radar.
(had a HRV salesman here pleasant enough but tried to scare me about mould etc - which I have gotten rid of - was much easier than I though, use a microfibre cloth and Move-it dilute with warm water and gently wipe the area)

All the whizz bang ones they show for the internal units are unavailable for split systems and seem to be only for 1 internal/external combination.

They haven't been all that convincing about what I am getting apart from jotting down a few part names (some of which were the wrong ones)

Wondering if I should go for bigger units and individual vs split - as I feel temps are rising.

and I will have to ask about noise for neighbours who have a door slamming fetish

and if WIFI control is worth it.
Any comments?

**Drew** · 23rd July 2016, 20:00

Are you talking about a 'multi'? One outdoor and a few indoor units.

Or ducted units?

**Voltaire** · 23rd July 2016, 20:12

In the 5 years I was installing heat pumps, only ever did one multi. It was a headache as one of the solenoids on the outdoor unit passed when

one of the indoor units was off and you could hear it. Probably better now.

I've got WiFi on my Mitsi in the lounge, used it once. Cheap enough for it as an extra but how much shit do you want to run off your phone

See a lot of HRV units, seem to rely on a good Salesman as they are nothing magic. Filters are expensive. Fit a Smartvent or something

without one sole point of sale.

Noise was an issue with R22 units years ago, less so with VSD compressors and low noise fans. Cheap ones have VSD noise which is annoying.

You probably would not want the outdoor unit facing the neighbours bedroom.

**Drew** · 23rd July 2016, 20:17

Originally Posted by Voltaire

In the 5 years I was installing heat pumps, only ever did one multi. It was a headache as one of the solenoids on the outdoor unit passed when

one of the indoor units was off and you could hear it. Probably better now.

I've got WiFi on my Mitsi in the lounge, used it once. Cheap enough for it as an extra but how much shit do you want to run off your phone

See a lot of HRV units, seem to rely on a good Salesman as they are nothing magic. Filters are expensive. Fit a Smartvent or something

without one sole point of sale.

Noise was an issue with R22 units years ago, less so with VSD compressors and low noise fans. Cheap ones have VSD noise which is annoying.

You probably would not want the outdoor unit facing the neighbours bedroom.

Done quite a few multis. Haven't had any issues with them. They're fucken expensive though.

The outdoor capacity is usually pretty high, so they can make a bit of a din if all the indoors are being asked to go hard at once.

**eldog** · 23rd July 2016, 20:19

Originally Posted by Drew

Are you talking about a 'multi'? One outdoor and a few indoor units.

Or ducted units?

From what I understand it's the following Daiken models
2 off Multi units
1 outdoor unit 3MXS68 supplying 2x indoor ones FFQ50 + FTXS25KVMA
1 outdoor unit 3MXS68 supplying 3x indoor ones FQ20 + FFQ25 + FFQ35
with
outside air being filtered and blown into rooms (low rate) after passing through a heat recovery ERS170 (heat exchanger) and some air sucked out of the hallway

less than 20 K installed, $190 per year annual service

After looking at the house initially thought a cassette unit would be better as it could drain away the condensate with out a pump (they don't want to install a pump)
the above part numbers will change as they may all be std wall units, if we can find a way to drain the condensate, without a pump.

I thought wrongly that I could use the 'latest' indoor units with the outdoor units but apparently I can't. from the inference I got it could be technical or just the supplier won't sell them with the multi one.

Going to change lights from mostly recessed to dim able LED so I can reinsulate the roof to Sth Is specs

going to see them again this week (so I can get a better understanding) and check out what happened to the Mitsi agent so I can compare apples and apples

and I can ask about the noise for the neighbours bedroom (who's hot!!!)

**Voltaire** · 23rd July 2016, 20:23

Originally Posted by Drew

Done quite a few multis. Haven't had any issues with them. They're fucken expensive though.

The outdoor capacity is usually pretty high, so they can make a bit of a din if all the indoors are being asked to go hard at once.

I only did one and supplier were unhelpful as I purchased it off one of their customers and it all got a bit messy....lessons learned

It was about 9KW and as you say was pretty loud at full load.