Heat pump versus air conditioner

happymullen, Jul 5, 8:28am
My unit in Mount Maunganui gets really really hot in the summer, has tinted windows, curtains and sun filter blinds, but the nights are too hot to sleep. Any suggestions on what would be the better appliance to install? I am wondering if you can put small air conditioner units just in the bedrooms, to use at night. Thanks for any comments.

mm12345, Jul 5, 9:58pm
"Heat pump" is a common NZ term for what's just called an air conditioner (perhaps "reverse cycle" AC) in many other countries.
Yes - sure you can put a small heat pump/air cond unit in a bedroom. You might want to make sure that the outdoor unit is mounted away from the bedroom a bit, on something solid (good thick concrete pad etc) and fitted with anti-vibration mounts. When the sales folks talk about how quiet their models are, they're referring to the indoor unit fans etc. The noise of an outdoor unit isn't usually a problem during daytime when there's always other noise in a house, but in the dead of night, the vibration / hum of it might be very annoying.

vivac, Jul 5, 10:00pm
Basically what mm12345 is saying is that a heat pump both heats and cools.

lissie, Jul 6, 5:03am
My completely useless heat pump (for heating) is an excelent air conditioner- however living in Wgtn that makes it useful about 3 days a year- you're get much better use !

jonners2013, Jul 6, 5:26am
have a look at multi-unit split systems, which are just like a normal heat pump but you can have more than one inside unit running off the one outside unit. sometimes they work out significantly more expensive than just having a number of individual ones, but sometimes it's worth it just so you don't end up with heaps of ugly outdoor units.

if you're flush with cash, also just look at going for a fully ducted system.

happymullen, Jul 6, 6:03am
Thanks for your comments, much appreciated. Hadn't thought about the vibration noise either, especially important to consider as my unit is located in a open village type situation, and I need to consider the neighbours. Is it the air con that makes vibrations? Do heat pumps do the same? Thanks

t_naki, Jul 7, 4:23am
heat pumps and air conditioners are basically the same thing. The only difference is an air conditioner doesn't have the reverse cycle and so cannot be used for heating. You will have to go exceptionally out of your way to find an air conditioner only, all systems you see marketed will do both. The outdoor unit will have a compressor and a fan, a cheaper model will make a bit of noise. If you go for an inverter model then the compressor will bu much quieter than a straight compressor model. The only thing is that the speed drives on some for the cheaper inverter models makes a high pitched whine that you won't notice till the dead of night. If you stick with the main manufacturers you will be pretty right and they will all state their inside and outside noise levels.

gedc, Jul 9, 8:53am
I personally can't vouch for a fully ducted system although your mileage may vary. We just put one in as the luxury part of renovations. $22K and that was a good deal through a friend compared to 3 other firms. Two zones in the house. 2 massive outdoor units each pumping out 11kw heat. Installed by a reputable firm. 9 weeks later and 19 visits including several by Fujitus they are about to remove one of the systems and we are going to put in a split hi-wall in the living rooms. They just don't heat the house very well ( in our experience ) and seem to try and defy the laws of physics i.e pump hot air out at ceiling level and suck it back in at ceiling level yet will still heat the room allegedly. On one day alone our electricitiy bill was $47 ! It's a VERY slow convection conversion of the cold in the room at body and feet level. It was taking rooms 3 hours to come to temp and some rooms just never made it past 18 - even after hours and hours. AND they aren't quite as silent as they make out to be - especially if the main air handling unit upstairs is above the living area as the ducted runs can't be more than 6 metres due to static pressures. They have tried pretty much everything possible and have agreed they can't get it to do " what it should". I can however vouch for normal hi wall or floor level heatpump consoles.

sailor13, Jul 9, 9:16am
We have got a Daikan realy good at heating and cooling we do not hear it much at all inside or out we are very happy with it we got it from All seasons Air Tauranga so easy to deal with.

jonners2013, Jul 9, 6:03pm
Gedc - if you don't like a ducted system because the air intake is at ceiling level, where do you think the intake is on a high mount split system?

The issue isn't the theory or design of the ducted system, the issue is that either they've installed the wrong units for your house and they are inadequate, or there is a problem with them or they just aren't very good.

happymullen, Jul 9, 7:32pm
Sailor13, do you use the air conditioner much? I have heard good things about the company you mentioned, so might pop in and see them.

vivac, Jul 10, 6:49am
Daiken are a Gree with a different outer plastic case and a bigger price tag.

sailor13, Jul 11, 9:19am
yes we do in hotter months all the time that was the main reason for putting it in plus in winter set on low and on auto keeps the house lovely and warm love it would not like to be with out its my best friend inside unit on the wall is plastic & the out side unit is a metal case I did not think it was any more to buy than others except the cheapys we have had it in since feb 2011 and not any problems.We clean the filters regularly.

paix1, Jul 12, 8:16am
. yep! And I have had 2 Fujitsu HP's and never ever again. Nothing but problems with both of them. Daikin and/or Mitsubishi Electric all the way now for me! (although don't need one in current house as have very efficient woodburner)

timbo69, Jul 12, 7:03pm
Interesting, my 12k ducted heat pump is now just an expensive heat transfer system for my fireplace.

timbo69, Jul 12, 7:12pm
I agree with him, I cant explain why but my system dont work very well either. I have a 14kw ducted system in my 104sq/m house - I was told to leave it on 24/7 to be most efficient - its too loud and cost me about $350 for the first month, subsequently I ran it for about 4 hours in the evening which took the edge off and cost me about $100-150 p/m. if it was cold in the morning I didnt even bother.

After 3 years I gave up and went back to fireplace - here are my temps this morning:


Stick your heat pump Id say.

velenski, Jul 13, 1:04am
-3.8 here this morning house warm 18.4 heatpump is great !

timbo69, Jul 13, 5:23am
Sounds way better than my POS heatpump but to be honest with young children I prefer to keep house at about 22 which was impossible/expensive with heatpump but easy with fireplace.

schnauzer11, Nov 24, 6:52am
Yuss! With you there paix. In the house I bought last July we have the king of all log-burners, and no need of other heating.Heaps of hot water, too. In the previous house, post-quakes, we had both, but only used the Daikin on occasional hot nights, to take the temp-down.We did not move because of the quakes, just a long-planned down-size. A key-seller for our next house was a log-burner, and we got a beaut!