Help me choose a heat pump [Archive]

Scaredy Cat

31st January 2005, 12:34

Hi,

We are currently renovating our lounge/kitchen at the moment and we are looking at getting a heat pump.

This is where I need some help, could those of you who have a heat pump/know about heat pumps give me your opinions of the ones you own/have worked with. This would include the pain of installation, price, reliability, noise both inside and outside, warranty problems, temperatures they work till etc.

The problem I have is that everytime I see a professional about it they claim that their one is the best. After some searching I found that Fujitsu have recently brought out a new version that works down to -15 degrees which is good for Dunedin winters:)

Anyway any help would be greatly appreciated. Thanks.

Hitcher

31st January 2005, 12:46

The most important thing to note about heat pumps is their location in the room. They blow air around and create a draft. If you don't like sitting down or sleeping in a breeze, then you could be in for some problems.

Otherwise heat pumps are magnificent and I am unsure why they haven't caught on more in New Zealand. Any form of heating/cooling that is 150-500% efficient has got to be good value.

Deano

31st January 2005, 12:47

Hi,

noise both inside and outside, .

Ive never measured internal noise but it would need to be insulated from the dwelling to prevent structure borne sound.

Be careful where you site it - Ive monitored three different brands of heat pump (Fujitsu included) that were located within 2 metres of the property boundary, and they did not comply with District Plan or NZ Standard recommended noise levels. (You can check your city's District Plan at the Council)

The noise output specified on the pump ranged between 40 and 60dBA from memory.

Depending on the background noise levels, you may be required to achieve as low as 35dBA at the boundary, possibly even lower.

Locate the pump as far away from your neighbours as possible. The ones I have monitored have all had to carry out some form of shielding, or relocate the pump.

sels1

31st January 2005, 13:59

Hi,
The problem I have is that everytime I see a professional about it they claim that their one is the best. .

Like many things these days they all come out of the same factory ( well 3 or 4 factories) with just cosmetic differences. Any of the major brands will do the job. There are some brands coming out of China that are cheaper...but you get what you pay for. (although some of the main brands are manufactured there now.)

After some searching I found that Fujitsu have recently brought out a new version that works down to -15 degrees which is good for Dunedin winters:).

Good feature - heat pumps were originally just adapted (with reversing valve fitted) air conditioners that were designed for warm climates and they struggled to produce much heat when the ambient temp dropped below around 5deg( some even had electic booster heaters) however modern units have overcome this to a large extent with improved coil and compressor design.
Fujitsu are a good recognised brand and if they are rating that model in that temp range then it could be your best option, considering Dn's climate. I recommend buying from a refrigeration/air cond company that can service what they sell, as opposed to appliance stores or power companies that just contract their installations out (sometimes to cowboys!)

Scaredy Cat

31st January 2005, 14:21

Thanks for all your help so far.

I contacted the DCC regarding noise and they said it would have to be 30 dBA or less at the boundary line to take into account the heat pump going at night. Now the heat pump pamphlet reckons that the noise level at the outside unit is 47 dBA at 1 m away. Luckily the heat pump would be right in the middle of both our neighbours about 4 - 5 m away from both boundary lines and would be facing the road which is very wide so the neighbours way across the street wouldn't be able to hear it (it doesn't matter anyway cause those neighbours have a lawnmowing fettish, they mow the lawns every 2 - 3 days and drives us nuts). The DCC said they could check the noise levels for us once the pump is in but if its not up to standard they could tell us to shield it or remove it which would be a waste of money putting it in the first place.

The internal noise is rated at 43 dBA at 1 m which is alot louder than mitsubishi which say 21 dBA for their units. But with the TV/stereo going hopefully it will drown the sound out.

Regarding a breeze in the room with the heat pump going, it doesn't really bother me as longs as its warm air. We are hopefully planning on going with a air conditioning company, my uncle is a plumber and has some friends so I will chat to him about it. I don't really want to buy it from applicance shops, we went into one and the salesperson said "what's a heat pump"?

Spin

1st February 2005, 00:22

Hey Scaredy Cat

We used to live in Dunners and had three separate heatpumps - two of them were actually inverters (more efficient)

The first one we had was a Fujitsu - worked fine but had more down time that the Daikens that we had subsequently - the two Daikens we had were great - and the installers were the best

We had the big ones - cost about $4500 - 7.7kw I think - you need the big ones for Dunners -..

Noise of things were no problem - either outside or inside - the old ones used to be noisy

We had the floor mounted ones - seemed to make the most sense to us - heat rising and all - but if you have kids they could be a problem with little fingers breaking bits off etc

Where you install it is crucial - as is the layout of the house - trust in your comon sense

Good luck - we think they are the only way to heat a house - clean, healthy, cheap to run, and amazingly convenient

Deano

1st February 2005, 08:29

I contacted the DCC regarding noise and they said it would have to be 30 dBA or less at the boundary line to take into account the heat pump going at night. Now the heat pump pamphlet reckons that the noise level at the outside unit is 47 dBA at 1 m away. Luckily the heat pump would be right in the middle of both our neighbours about 4 - 5 m away from both boundary lines

47dBA @ 1m will equate approximately to 37dBA at 4m and 32dBA @ 8m, so be wary about meeting the 30dBA limit.

Insist from the pump installer/seller, that the operation of the pump will meet all relevant rules and regulations, particularly noise. Then if someone complains and remedial work is required, you can put the onus back on the pump company. This happened with a job I was working on and the company paid to have a shield installed - basically a 12mm plywood tunnel (to allow airflow) lined with carpet underlay.

In another example, a different company were reluctant to use a similar tunnel as they said it would decrease the efficiency of the pump, and so they lined the boundary fence with Hardies board instead. This closed up all the gaps in the fence but I don't think it has yet acheived a "reasonable" noise level. This job still ongoing.

pete376403

1st February 2005, 15:47

Heat pumps are something I've been thinking about as well. Anyone have any opinions on the units offered by this outfit?
http://www.trade-me.co.nz/House-garden/Heating-cooling/Air-conditioners/auction-21937405.htm

geoffm

1st February 2005, 18:55

I can't help you with installers in the Deep South (there are a few in Auckland I wouldn't touch...) but get a proper air conditioning co to install it, otherwise the compressor warrenty is void. You should purge the lines with nitrogen before brazing to stop lumpy bits being sucked into the compressor from the oxidised copper pipe.
There are limitations on line size, length and vertical rise of the connecting pipes between the indoor and out door units. RTFM. You will also need provision for a condensate drain from the indoor unit, so consider where this is going to run.
Get the company to do a heat load calc on the house to make sure you get the right size for your house. If they won't do it/ give you a blank look, go elsewhere.
Geoff

Kickaha

1st February 2005, 19:10

I have a Panasonic CS-G123KE 3.45kw cooling/4.80kw heating ,when I first got it I found the noise fron the inside unit intrusive but after a few days I didn't even notice it any more,air flow direction can be directed by the unit using the remote control

As for the outside unit I suppose it makes some but I haven't ever heard it

In winter in Rangiora the ouside unit wll shut down to defrost if it gets to cold and this sometimes takes 10-15 minutes and the room temperature will drop noticably in that time,I've been told the Daikin are better in that respect

It makes a difference of about $30 a month to the power bill through winter with it being used for about 5 hours a day,the only thing I dont like about it is that you can only set it to turn on and off once per day instead of turning on before you get up and off when you leave for work and coming on before you get home again

gav

1st February 2005, 19:31

We installed a Mitsubishi MSH-18RV and have found it to be bloody marvelous. Real good in summer as a cooling aid too.
Best thing is maybe ask for a free quote, and they can measure size of room and recommend what size unit is suitable for your living area. Once you know what you need you can then shop around for what is going to do the job.

Scaredy Cat

2nd February 2005, 07:54

47dBA @ 1m will equate approximately to 37dBA at 4m and 32dBA @ 8m, so be wary about meeting the 30dBA limit.

Insist from the pump installer/seller, that the operation of the pump will meet all relevant rules and regulations, particularly noise. Then if someone complains and remedial work is required, you can put the onus back on the pump company. This happened with a job I was working on and the company paid to have a shield installed - basically a 12mm plywood tunnel (to allow airflow) lined with carpet underlay.

In another example, a different company were reluctant to use a similar tunnel as they said it would decrease the efficiency of the pump, and so they lined the boundary fence with Hardies board instead. This closed up all the gaps in the fence but I don't think it has yet acheived a "reasonable" noise level. This job still ongoing.

Thanks for that, more to think about I guess. Here is another question, if the fan etc of the heat pump are not pointing at either boundary but parallel to them would that make a difference in terms of noise?

Deano

2nd February 2005, 08:19

Thanks for that, more to think about I guess. Here is another question, if the fan etc of the heat pump are not pointing at either boundary but parallel to them would that make a difference in terms of noise?

I vaguely recall checking that out and from memory it was a very small difference - perhaps 1 or 2 dBA but I can't be sure sorry.

Skunk

2nd February 2005, 09:14

I was told to bypass heat pumps and go for a HRV system. Anyone got comments (the Poms maybe... I was told they are popular over there :bleh: )

pete376403

2nd February 2005, 10:19

I was considering putting the outside unit up on the roof (odd shape house, where I want the interior unit is close to the centre of the house). The guy advertising the units on trade-me (earlier post) said this is do-able. Would also get the fan further from the boundary.

sels1

2nd February 2005, 12:08

I was told to bypass heat pumps and go for a HRV system. Anyone got comments (the Poms maybe... I was told they are popular over there :bleh: )

Heat pumps use a mechanical refrigeration process to deliver low cost heating in winter and cooling in summer as well as air filtration and circulation. The amount of circulation depends on type of system - ducted or freestanding split-system.

HRV will not give you all these features - you get what you pay for. But it is really up to what you want and what your application is. (And how much you want to spend)

And perhaps the poms dont require any real cooling in their summers :)

Skunk

2nd February 2005, 12:22

HRV will not give you all these features - you get what you pay for. But it is really up to what you want and what your application is. (And how much you want to spend)Umm, yeah I know the mechanical differences, it's the real world differences I want to know.
Cheers for the reply (I should be clearer - but I know what I mean) :lol:

thermodix

25th February 2009, 04:57

I think if you doesn't care with the mechanical things then just with the prices.... take a look at here guys.... http://www.heat-pump-reviews.com/heat-pump-prices.html some heap pump reviews guys... jope this help you a little guys....

_________________
Programmable Thermostats (http://www.prothermostats.com/)

98tls

25th February 2009, 05:24

Have a Panasonic 6.5 best thing ive ever done,most important to get the right size,to small just causes endless problems.

JacksColdSweat

25th February 2009, 08:23

I was told to bypass heat pumps and go for a HRV system. Anyone got comments (the Poms maybe... I was told they are popular over there :bleh: )

I have an answer to this below...

We have a Mitsi 6.5KW in our 90sqm and it warms the entire house because we placed it right

We set it to 20 degrees in winter and it warms the lounge to 20 and the bedrooms to 19.

Our house has Pink Batts 3.2s in the ceiling and nothing in the walls. Nothing under the floor

More important than noise is the lowest operating temperature and where you place the outside units. If you place it on the Southern side of the house it will be colder than the outside temperature and your unit will turn off regularly to defrost itself - especially in the morning

Our unit works down to -15C but a LOT of them don't - some don't work below +10C - so your heat pump will spend a lot of time on the coldest days defrosting itself - and when it's defrosting it can't heat

Check the lowest operating temperature.

The noise is about as loud as a fan on medium setting when the heat pump is pumping full speed - doesn't bother us at all

HRVs and the like only work:
1) If you have a north facing house
2) You have a BIG roof cavity with suitable materials on the roof for containing heat within
3) you are prone to damp and mildew

I don't recommend them - they are not even close to the league a heat pump is in

We got the 6.5Kw from Hometech www.hometech.co.nz - I totally recommend them - they were excellent and did a nice install - very discreet and properly weather proofed since they have to drill thru your wall

it cost $3300 for a 6.5KW Mitsi - we're delighted - best money ever spent

Our house was 4 degrees inside the day it was installed - 1.5 hours later it was 16 degrees everywhere - when we added the pink batts a year later we can now keep it at an even 19 and the air is dry

Heat Pumps are the ducks nuts!

yungatart

25th February 2009, 08:24

We have a Daikin. It is brilliant. Quick clean and quiet, both inside and out. We never hear it.
Get advice from a specialist as to the best size and location for your needs.

Dooly

25th February 2009, 08:28

We have a Daiken unit. Can't recall the size but we went to a bigger unit than was needed. More is better!!!

Its great as I programme it to come on about 2pm in Winter so the house is warm when we walk in after work.

I use the fire in the weekend when home but the heat pump is good for quick heat.

JacksColdSweat

25th February 2009, 08:29

They (Heat Pumps) are not cheap to run

The marketing bollocks of "$4 heating for $1 power" is marketing hype which is intended to mislead you

The cost of our power went up 4 times in one year so it's hard for me to know exactly what it cost (I don't count units) but I would estimate we spend around $65 more per month in winter to warm the house

We were spending around $30 on gas heating which only warmed a section of the lounge - so I really don't care about the extra expenditure since the house is now dry and warm

I really don't care about the extra cost - I just can't believe how well these things work and I'm delighted with the result - I never knew a NZ house could be so warm...

Tank

25th February 2009, 09:23

We put one in last week.

Its a Dakin.

The level of professionalism between Dakin and Fujitsi / Mitsi was worlds apart.

Couldn't recommend them strongly enough.

Very quite, 6kw unit in lounge, $4.5k (harder then norm install)

Finn

25th February 2009, 09:43

I was told to bypass heat pumps and go for a HRV system. Anyone got comments (the Poms maybe... I was told they are popular over there :bleh: )

HRV systems take advantage of poorly built NZ homes by exchanging air between paper thin walls and shanty town roofs. Sure, it can change the temperature by a degree or two and the same time circulate moisture and mold, but in short, nothing will beat a heat pump.

Max Preload

25th February 2009, 14:41

HRVs and the like only work:
1) If you have a north facing house
2) You have a BIG roof cavity with suitable materials on the roof for containing heat within
3) you are prone to damp and mildew

I don't recommend them - they are not even close to the league a heat pump is in.

Except maybe in capital cost... :msn-wink:

The marketing bollocks of "$4 heating for $1 power" is marketing hype which is intended to mislead you.

When is marketing ever anything but? "15-50% off everything in store!" ring a bell? How about "Up to 50% cheaper than other brands!"?

But you're correct. The advertised CoP of a heat pump is difficult to achieve in anything but ideal conditions. One of the key conditions for ideal operation are a lowest temperature differential between inside and outside.

That said, they're never going to be anywhere near as bad as an electric heater which works in the high 90% range of efficiency. You mentioned you're now maintaining a steady temperature in your home - to do that with other methods of heating would cost you a hell of a lot more.

Winston001

25th February 2009, 15:16

HRV systems take advantage of poorly built NZ homes by exchanging air between paper thin walls and shanty town roofs. Sure, it can change the temperature by a degree or two and and the same time circulate moisture and mold, but in short, nothing will beat a heat pump.

Agreed. My parents installed an HRV despite my misgivings and it made no noticeable difference at all. Tile roof with lots of air circulation, there was never going to be much warm air to pump back into the house. Even the addition of a heater in the ducting made no difference.

An HRV will work properly in the right type of house but the sellers don't care about that.

Heatpump beats it hands down.

JacksColdSweat

25th February 2009, 20:13

Except maybe in capital cost... :msn-wink:

...

That said, they're never going to be anywhere near as bad as an electric heater which works in the high 90% range of efficiency. You mentioned you're now maintaining a steady temperature in your home - to do that with other methods of heating would cost you a hell of a lot more.

Actually my point around the heat pump and HRVs still stands

An HRV is cheaper to install - but it doesn't (really) heat your home - it dries it - hence my saying they are not in the same league

You get a degree or two more warmth - not the change we got from 4 degrees inside one morning to 16 an hour and a half later (yes, I'm so anal I watched the thermometer)

I agree with you totally - traditional resistance heaters are SHOCKINGLY expensive for no real gain and gas heaters just pump more moisture in

As I said before - ours costs us around $65 per month in winter and I have no regrets - the whole house is warm and dry - and it's a crappy 1979 New Zealand masterpiece of thin fibrelite, corrugated iron and MDF floors...

Skyryder

25th February 2009, 22:23

Mitsibishi.

Skyryder

Burtha

26th February 2009, 11:37

Hiya
When we bought our place there was already a new fujistu in it. We're in Nelson and although pump only goes down to 18 degrees thats low enough for me and I quite a fussy pots so 15 would be ample.

Ours is big, isnt too loud, outside is well inside boundary so no probs there, inside is quite breezy but we can set fan direction, hot / cold, humidity, etc. Although we have it on auto most of the time having a full range of options is usefull esp if the house gets steamy, or your trying to dry clothes & stuff.

Tis also VERY economical.

vifferman

26th February 2009, 12:09

Mitsibishi.

Skyryder
Didja mean "Mitsubishi"?
If so, which - Mitsubishu Electric, or Mitsubishi Heavy Industries?
According to our installer, the latter has more experience and is a bigger player in the market (especially commercial), and most of it's R&D is passed on to its sibling, Mitsubishi Electric, who deal more with home appliances.
At his recommendation, we opted for the Mitsubishi Heavy Industries models (we have two), as they rated marginally better on the specs for energy consumption and noise output.

My in-laws bought two Panasonic units - they're smaller and less obtrusive than ours, but noticeably less effective (despite their house being newer and better insulated than ours). They bought Panasonic mainly because they were the only company to offer a unit with a self-cleaning filter. Unfortunately, because NZ gets whatever models Australia decides are best, and Aussies go for performance and value-for-money over features, by the time my father-in-law got around to ordering his, they weren't available any more.

Max Preload

26th February 2009, 16:12

Actually my point around the heat pump and HRVs still stands

An HRV is cheaper to install - but it doesn't (really) heat your home - it dries it - hence my saying they are not in the same league

You get a degree or two more warmth - not the change we got from 4 degrees inside one morning to 16 an hour and a half later (yes, I'm so anal I watched the thermometer)

I agree with you totally - traditional resistance heaters are SHOCKINGLY expensive for no real gain and gas heaters just pump more moisture in

As I said before - ours costs us around $65 per month in winter and I have no regrets - the whole house is warm and dry - and it's a crappy 1979 New Zealand masterpiece of thin fibrelite, corrugated iron and MDF floors...

I was commenting on them being in the same league price wise - last time I checked the HRV wasn't far off the price to a heat pump and they're certainly not in the same league performance wise.

As a side note, people often make claims about excessive power consumption from oil column heaters and they won't listen to the fact that they use no more power for the same heating effect as a fan, panel or bar heater i.e. their efficiency is the same. But oil column heaters have to be used differently to get the same result. The heat that remains in a oil column heater is not utilised if you switch it off just as you go to bed - they should be turned on about an hour before they're actually needed and turned off about an hour before the time they're no longer needed as their effect is not immediate - it lags due to the need to heat the oil before the heat is felt in the room.

vifferman

26th February 2009, 16:22

As a side note, people often make claims about excessive power consumption from oil column heaters and they won't listen to the fact that they use no more power for the same heating effect as a fan, panel or bar heater i.e. their efficiency is the same. But oil column heaters have to be used differently to get the same result.
I think part of it is that oil column heaters have been hyped up to be more economical and safer than other heaters. The problem is they take longer to give out heat, and they don't circulate the heat at all.

HRV is similar in that sales seem to have been driven by some hype and exaggeration of the effectiveness of the units. My beef is that for what they are, they should be cheaper, and for what they cost, you're far better off spending a bit extra and getting a heat pump.

Before we had aircon installed, we had a large firebox in our lounge. We ripped it out because of the mess from ash and smoke (if it was a gusty night, smoke would puff out of the firebox or flue into the lounge). Also, I was the only one who took care of lighting it, cleaning out the ash, cutting up wood, etc etc.
We ripped it out, and were going to install a gas heater (had them in three other homes) when we realised if we got a heat pump instead we could use it in the summer as well. One of the better decisions we've made.

Fatjim

26th February 2009, 16:57

Actually oil coolumn heaters make you feel warmer than a fan heater for the same heat output. They also maintain a steady heat in the room.

But 1kw of heat is still 1kw of heat.

Max Preload

26th February 2009, 17:50

I think part of it is that oil column heaters have been hyped up to be more economical and safer than other heaters. The problem is they take longer to give out heat, and they don't circulate the heat at all.

I've never seen any such claims of better economy. They're certainly safer around children and pets as the surface temperatures are considerably lower than that of a bar heater. They circulate heat but most by convection so you do get uneven temperature across the room.

HRV is similar in that sales seem to have been driven by some hype and exaggeration of the effectiveness of the units. My beef is that for what they are, they should be cheaper, and for what they cost, you're far better off spending a bit extra and getting a heat pump.

Absolutely. HRV & DVS systems should be much cheaper. Heat pumps are priced about right for the return in savings.

Actually oil column heaters make you feel warmer than a fan heater for the same heat output.

Only because of the fan - if you're not sitting directly in front of a fan heater it'll feel similar and heat the room more evenly.

Lias

27th February 2009, 08:32

It should also be worth noting that if you have asthmatics or allergy sufferers in the house, the best brand is a Fujitsu for their plasma filters.

Fatjim

27th February 2009, 08:46

Absolutely. HRV & DVS systems should be much cheaper. Heat pumps are priced about right for the return in savings.

This pisses me off in two ways. Firstly the people that get ripped off for a DVS system thats a $50 fan and a bit of tubing. The most expensive bit is th controller, but you pay extra for that!

Secondly, why should stuff be solely priced on what it saves you, why bother buying something for $5000 to line the pockets of someone when it only saves you $500 over 10 years. This is the case in heat pump hot water systems. I think they are a great idea, but why spend an extra $3000 getting one? This is one area where I think the gummint needs to step in. Although I'm not sure what they could do.

Kiwi Graham

27th February 2009, 08:47

I've got three....Fujitsu's. There quiet and do exactly what there supposed to. You get a six year warrenty with them as well.
Careful siting is important but the consultant will help you with that, their multi directional anyway.
In this current climate you should be able to do a deal on price!

vifferman

27th February 2009, 09:28

Actually oil coolumn heaters make you feel warmer than a fan heater for the same heat output.
You're not supposed to sit on them, y'know... :confused:

BMWST?

27th February 2009, 10:03

despite the hype,and misleading names,HRV is only a ventilation system,that takes advatage of warmer air in the roof space.They are not a heating system.
A heat pump is very efficient in that it is not "making" heat,it transfres heat from outside to inside(or visa versa) in exactly the same way a fridge transfers heat from inside to outside
If you are considering heating in Dunedin,have you considered a pellet burner.?

Max Preload

27th February 2009, 10:23

...why should stuff be solely priced on what it saves you, why bother buying something for $5000 to line the pockets of someone when it only saves you $500 over 10 years. This is the case in heat pump hot water systems. I think they are a great idea, but why spend an extra $3000 getting one? This is one area where I think the gummint needs to step in. Although I'm not sure what they could do.

You lost me here. As far as I'm concerned that is the primary criteria - no point in it costing more than it's going to save you in its useful life. That's not to say I would object to it costing less and the payback time being less.

vifferman

27th February 2009, 11:14

You lost me here. As far as I'm concerned that is the primary criteria - no point in it costing more than it's going to save you in its useful life. That's not to say I would object to it costing less and the payback time being less.
?
Now you've lost me.
My primary criteria was to get some heating for the lounge. When I realised I could cool the lounge in winter as well, I changed from a gas heater to aircon, and got it for the basement as well. Being more cost-effective than any other form of heating was just an added benefit/incentive, not the primary one. It's not making money - it's a straight cost, albeit less than any other form of heating. However (but!) that's kinda negated by using it to cool the house in summer, as if I'd got some other form of heating there'd by no costs in the summertime.

Frankly, I don't really care. I just have to accept I have three parasites that cost me lots of money: each month I fork out $300 for power, $200+ for teh Interdweeb, and about $1500 for food and drink. I've given up trying to actually save any money. :blank:

0lddog

17th April 2009, 06:49

HRV is similar in that sales seem to have been driven by some hype and exaggeration of the effectiveness of the units. My beef is that for what they are, they should be cheaper, and for what they cost, you're far better off spending a bit extra and getting a heat pump..

Top of the morning from the Emerald Isle,

Its not really a case of HRV replacing a heat pump

HRV requires an air tight building that is very insulated. Otherwise its a waste of time ( er, thats money that I mean )

Most of the heat pump makers also offer HRV units that integrate into the their heat pump duct indoor units.

Mitsi have the losnay ( loosnay ? ) Daiken have one too

In the case of mitsi they have a 7 day controller that you can set up to control both the heat pump and HRV.

Does Dunedin really go down to -15C in winter ?

davereid

17th April 2009, 08:50

Do they save much money ?

Say 5 kw conventional heater, using 5 kw power for 5 hours a day @$0.20 kw/hr. $5 day running cost or $450 per year if you heat every day of winter.

Heat pump will cost possibly as little as 1/4 of that amount, but likely closer to 1/3, say $150 per year.

This saves $300 per year.

If your heat pump cost $4000 installed, you will break even after 13.3 years.

If you still own the house, and the heat pump is still going well, and hasn't required any repairs that is.

Of course, if you use the heat pump more, or for longer you will have a shorter rate of return, and if you use it less, a much longer period will be required before it can be considered a good investment.

On the other hand, if you chucked the $4000 in bonus bonds, and managed a real 4% return you would earn $160 a year in payouts. Which if they went on your power bill, would give the heat pump a 27 year break even point.

Winston001

18th April 2009, 21:37

Does Dunedin really go down to -15C in winter ?

Sure and its fine to be hearing from the land of the Little People. :clap: As for Dunedin.....15 degrees of frost? No.

It certainly gets cold and damp in the bottom of the valleys but not -15.

Do they save much money ?

Say 5 kw conventional heater, using 5 kw power for 5 hours a day @$0.20 kw/hr. $5 day running cost or $450 per year if you heat every day of winter.

Heat pump will cost possibly as little as 1/4 of that amount, but likely closer to 1/3, say $150 per year.

This saves $300 per year.

If your heat pump cost $4000 installed, you will break even after 13.3 years.

If you still own the house, and the heat pump is still going well, and hasn't required any repairs that is.

Of course, if you use the heat pump more, or for longer you will have a shorter rate of return, and if you use it less, a much longer period will be required before it can be considered a good investment.

On the other hand, if you chucked the $4000 in bonus bonds, and managed a real 4% return you would earn $160 a year in payouts. Which if they went on your power bill, would give the heat pump a 27 year break even point.

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.

Never mind. People who install heatpumps say their power bills don't change, in fact may rise a little, but the vast improvement in warmth and dryness of the house is worth every cent. Marvellous.

normajeane

18th April 2009, 22:48

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.:clap:

Max Preload

19th April 2009, 00:31

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

........... 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. :clap: