[zardell]

I've found a problem with our heat pump and wonder if any of you have had the same experience.

Now, call me stupid, but I want to put on the heat pump when it's cold and believe me, there have been some bone chillingly cold nights and early mornings lately.

Now, we live in a brand spanking new single story home with good insulation - no double glazing though.

Anyway, now the weather has turned really quite cold, our heat pump is only blowing out warmish air and no matter what we do, we can't get it any hotter. So we called in 'The Man', in fact we called in a few men to get varied opinions.

They all came up with the same conclusion : yes, our heat pump is big enough to do what we are asking of it, but apparently, because (like all heat pumps) it draws in cold air from the outside then warms up said air as it passes through the unit and then blows it into the room, it will only blow out really hot air if the outside air isn't too cold !!!!!!!!

The 'Man' that came to look at it this morning confirmed it yet again by saying 'Oh, it's frosty this morning, so the air from the pump won't get hot.'

Just going out now to buy a gas fire - we have mains gas so I can buy one of those Rennai flue-less heaters - oh and then (apparently) I'll have to turn the dehumidifier up too - happy days.

Julie

xx

[CjChris]

I had a heat pump for years. It blew out hot air in the winter no matter what the temp was outside. If I set the thermostat on a hotter temp, it got the house toasty warm and kept it at that temp until I lowered the thermostat.

What's the point in having one of those things for heat if you only "sort of" get the house warm?

Sorry, I'm no help, really, but I don't understand why your heat pump is acting this way, either!! What a pain!:wah

[zardell]

If I set the thermostat on a hotter temp, it got the house toasty warm and kept it at that temp until I lowered the thermostat.



Tried running it as hot as it will allow (30 deg) and it makes no difference.

Utterly useless thing !!

Julie

xx

[hball]

I understand that a heat pump sucks in cool air from inside the house, sends it through it's heating system (situated outside the house) and then blows the warm air back into the house. Then it gathers the cooling air and does it again. Ours works on a thermostat so the temperature is maintained.

I was also told that the colder it is outside the more effective the unit is supposed to be.

Mind you I'm no expert!!!

[Joanne100]

Dont know how it works but ive been told the same, if its really cold outside it wont heat up the same..............strange hey!
Sorry im no help at all :p

[hball]

:confused: Sudden thought -

...Just remembered, heard recently of a similar situation to yours and the problem was that the unit needed re-gassing. Once that was done there was no problem!

[BaldyBeardyBloke]

Does that mean that in the summer the air will be too hot outside for the pump to cool it properly ? This doesn't sound right to me, but I aint no heat pump expert, so who knows.

Take it outside and hit with something heavy. It won't make it work any better, but it'll make you feel great and might even warm you up too :laugh

[martinp]

Heat pumps warm the air indoors by pulling heat from the outside air by attempting to cool it. So when you need warmth the most, the unit attempts to cool down the outside air which is already quite low, so it's hard work for the unit which if not operating at top efficiency may show reduced performance

We had a frost this morning, so around 0 deg's outside but our heat pump was powering hot air out.

In the summer it works in reverse, and the pump attempts to heat the outside air while cooling the inside, so if it is very hot outside, a similar lowering of performance can sometimes occur.

Most modern heat pump are designed to work with outside temperatures of between -10 and +40 degs C, but you may want to check the spec on yours.

Heat pumps don't actually heat the air indoors they just transfer the heat from outside. Some heat pumps for use in very cold areas have secondary heaters which kick in when the outside temperature drops below a certain level.

The suggestion it may need re-gassing is worth following up and I am surprised none of the experts suggested this.

[katandbob]

Julie, we had one in the rental - I wouldn't get one in our house if I was given one! it did the same, if it was freezing it would go into defrost mode to defrost off the ice on it outside,... it also made a big puddle underneath - which would freeze to make a nice booby trap for an unsuspecting visitor LOL

it blew the gas line out in the end (*cheap china model) but we left before we had any more cold days to try the replacement in the winter.

Good luck with the fire - I need to get a dehumidifier too.

Kat

[zardell]

The suggestion it may need re-gassing is worth following up and I am surprised none of the experts suggested this.



What does re-gassing mean?

Also, this is a brand new pump and the man who came to inspect it on the suppliers behalf said it was working fine, hence we got in other 'men'.

You're right Martin - we need an expert.

Thanks for all your replies..........:nice1

Julie

xx

[kanatakiwi]

I'm not sure but is there a difference between a heat pump in north america and NZ? because all the heat pumps I knew about in North America were able to belt out the heat no matter what the weather outside, but here I have heard from many that they dont really heat the house in the winter because of this taking cold air from outside. seems like a heat pump should be able to heat!! a heat pump here (NZ) sounds more like an air re-circulator to me.

[olivia]

Our heatpump which is only a couple of months old has the defrost function that Kat mentioned. For the 10 minutes when it is defrosting no air is pumped at all but the rest of the time we are 'roasty toasty'.
What make have you got? ours is Fujitsu.

Hope you get it sorted.

Olivia

[martinp]

What does re-gassing mean?


Hi Julie,

A heat pump forces a refrigerant gas around a closed system extracting heat from the outside air and transferring it indoors. This is like a fridge where the inside of the cabinet is made cold, yet to do that the back of the fridge is warm. Imagine your indoor unit is the back of the fridge with fans that blow air over it to transfer the heat into the room.

If the gas is low in volume it will not work efficiently.

When a heat pump is installed, it has to be gassed, or charged as it may be called. The inside unit, and the outside compressor, are fitted wherever and then piped together. it is then charged up.

Maybe yours wasn't properly charged up at install.

What sort of outside temperature did you get to notice this poor performance?

[zardell]

What sort of outside temperature did you get to notice this poor performance?



-1. Although having said that, even in warmer temps it has never sent out hot air, always been more like warm air.

All I can tell you is that it is a Panasonic and it can be used as an air conditioner in summer.

Julie

xx

[auskiwi]

Heat pumps in NZ are quite different to the ones in the U.S. Here they are little thingys that are attached to your wall (inside your house) and blow warm air out of the actual unit. What we are used to in the U.S seems to be referred to exclusively as 'central heating' here in NZ.

Amy.

[BaldyBeardyBloke]

Now this could get really confusing. Central heating is something quite different again to someone from the UK.

To my completely untrained mind if it will never blow hot then it aint working properly. Sounds from what has been said thus far that the re-gassing option is well worth a bit more investigation.

[martinp]

All I can tell you is that it is a Panasonic and it can be used as an air conditioner in summer.
I think you need to get someone in recommended by Panasonic to look at it. Unless it is a very small unit, this really is not how it should be working at -1 C.

Try contacting Panasonic NZ and complain about the poor performance. In my experience every NZ supplier I have contacted has been more than helpful to resolve any problems.

[Sam B]

We have very similar units at my office in Tokoroa. Today it blew luke warm air in to the office until about 11am, then as it got hotter outside, the air got hotter until the office was stifling. Great (not).

[zardell]

then as it got hotter outside, the air got hotter until the office was stifling.


Stifling sounds good to me right now......:laugh

Thanks everybody for all your comments. It's much appreciated.

:nice1

We'll get it sorted, but in the meantime I refuse to be cold, so I went out today and bought a (mains) gas heater. It's being delivered tomorrow so watch this space.......

Julie

xx

[Carol]

I'm sitting writing this under a wonderful blast of hot air from my central heating.

I would never buy another house in New Zealand without central heating.
I didnt move half way around the world to put up with a freezing cold house. Your quality of life is meant to be better here - not worse.


Crank that fire up Julie!
You go girl!
:clap
And if I was you I'd have the useless object returned and my money refunded.

(Feeling particularly bolshy today I am! ;))

[ellenmelon]

i cant remember what show it was on, but they were talking about how there was an assumption that heat pumps would emit constantly hot air...as others have said it depends on the outside temperature/roof space temp as to what temperature it ends up being in your house.
its sposed to be good for keeping your house dry though..

[Croft]

From reading around the net I've found:

Not so good in low temperatures

Extracting heat from outdoor air gets more difficult as the temperature drops. Sometimes, especially on frosty mornings, exterior heat pump units freeze-up and have to stop working for several minutes while they defrost. This can happen to all heat pumps but some do a better job of cold-weather performance than others. A heat pump will not operate very efficiently if the temperature regularly gets down to around -10°C. In fact it may be no better than a plug-in heater. Ask suppliers for the heat output figures at an external temperature of 2°C. The higher the figure the better.

http://www.trademe.co.nz/Partners/Content.aspx?id=73

and

Very cold weather forces the heat pump to work harder to extract heat from the cold air. This causes the compressor to operate longer. A heat pump can have as much as 15 kilowatts of supplemental electric resistance heating strips to provide heat during very cold weather. When these strips are in use, the hourly cost of operation rises dramatically.

http://www.sdge.com/forms/heatpumps.pdf

and

Heat pumps work very efficiently when the outdoor temperature is in the 50 F range. As the outdoor temperature drops, the heat loss of a home is greater and the heat pump needs to operate for longer periods of time to maintain a constant indoor temperature. Around 37 F many heat pumps reach what is called the balance point. At or near this temperature the heat pump needs to run constantly to produce enough heat to maintain a comfortable indoor temperature.

As the outdoor temperature continues to drop, the heat pump needs help from traditional electric resistance heat coils. These coils resemble the glowing wires inside your toaster and consume vast amounts of electricity as they burn to keep you warm. Your thermostat will most probably have a light that comes on when this happens. It is usually labeled as emergency or auxiliary heat. If this light is on whenever your heat pump is working, you should have a professional service your system.

http://www.askthebuilder.com/294_Heat_Pumps_-_How_Well_Do_They_Work_.shtml

[Croft]

Just found this from an NZ Government website.

http://www.eeca.govt.nz/labelling-and-standards/heating-and-cooling/air-con-label.htm

You get star ratings for heating and cooling efficiency - a full explanation here:

http://www.eeca.govt.nz/labelling-and-standards/heating-and-cooling/choosing-a-smart-heat-pump.html

You can also compare products at this Australian Government website:

http://www.energyrating.gov.au/appsearch/air_srch.asp

Not so good if you've already got one, but good resources for those in the market.

[zardell]

Thanks for all the links Croft.

Now, when I talk heat pumps to the powers that be, I will have a much better understanding of what's going on.

Thanks one and all.

Julie

xx

[Andy-Dee]

Carol - you said CENTRAL HEATING - pray tell do you mean Central Heating or is that a Kiwi'ism for sort of Central Heating - that really isn't!!!!!!!

I hate to labour the point or hi jack Julie's thread but its the first time I've heard the magic words uttered from someone in NZ.

If you've got it, where do you get it from and how much does it cost?? Actually don't care how much it costs.

[clg]

"central heating" in NZ means some sort of heating for each room in the house with a thermostat. It most often is gas ducted, which has a duct blowing hot air into each room. There are also radiant heat systems around as well but gas ducting is more common. We have a radiant system which we installed after we bought our house which works fine. You can also do very well heating a house with a wood burner and DVS, our neighbours have a setup like that and it keeps almost all of their house warm.

[hball]

We have 'central heating' too! Ours is in the slab and warms the floors, so warm and toasty when you walk on it with bare feet even when it is FREEZING outside! It is thermostatically controlled so that we can adjust different rooms to suit.

We also have minimal carpeting and maximum hard floor (slate in our case) and have positioned the house to maximize the suns energy which then reduces our need for the CH!!!

Couldn't, wouldn't live without it!

[aberdian]

How do they compare to ground flow heat pumps? - we nearly installed one here in the UK but would had to rip up our newly laid floors. Wasn't meant to be.....

[Super_BQ]

IMO, Heat pumps work better as cold air conditioners than hot air. If the system was ever proven effective enough, the we would see air conditioners in cars that work in inverse mode (pump out heat).

The heat pump installed where we live in Christchurch also doesn't work that well near 0°C. As mentioned before, the efficiency is pretty much close to 0% when operating below freezing point. The rating of heat pumps is also controversial in NZ. At freezing point, the most heat you would get is simply the amount of kW power drawn from the house's electrical supply. Being single phase 240 volt, the heat pump won't draw much more than 3000 watts continuously. Unless your house is poorly insulated and the rooms are not air tight, 3Kw of power should be more than plenty to heat a bedroom.
The question is how fast do you want to warm up the room? The faster you want heat, the more power is required. Another problem with heat pumps is latency. You won't get instant heat at turn on like you do with a portable electric heater.

I'm a big fan on oversizing or over-engineering. The reasons why N. American heat pumps manage to extract heat even at below 0°C is because of the size of their heat pump units. There is no doubt that a bigger heat pump exchange (the unit that sits outside) will do a better job than a small unit. In fact, many of the heat pump units installed in NZ are not suitable for N. American climates. The only heat pumps that interest me are the ones that are the size of a kitchen refridgerator or specifically made "cold heat pumps" that are designed to extract heat from cold cold air (dual stage design).

[nickydwuk]

If a property states heat pump - will it have a heat pump in every room or just one in the main room? Is there a way of circulating the heat around the house if just one pump?

[peebles16]

Just one room Nicky maybe two if you open all the doors and haven't come across one that is pumped into other rooms as yet :( Although I believe you can duct them through if installing new ones but someone else may be along to tell you more :yes To be honest as stand-alone heating source they are not great in my opinion unless like me you like sitting underneath them :laugh

Karenx

[nickydwuk]

So apart from getting central heating (to radiators) installed what is the best method of heating? I thought heat pumps were a step up from log burners.

[Philip10]

They all came up with the same conclusion : yes, our heat pump is big enough to do what we are asking of it, but apparently, because (like all heat pumps) it draws in cold air from the outside then warms up said air as it passes through the unit and then blows it into the room, it will only blow out really hot air if the outside air isn't too cold !!!!!!!!


Julie

xx

Sounds like a heater I had in 20 year old Land Rover. :laugh :laugh :laugh Don't know why I'm laughing, due to hit NZ for a Southland winter. :uhoh where it's warmer in the kitchen fridge then the front room.

[IanW99]

So apart from getting central heating (to radiators) installed what is the best method of heating? I thought heat pumps were a step up from log burners.

Heat pumps are one of the most efficient forms of heating with electricity which is why they are quite common. But converting electricity to heat is very inefficient method anyway.

With heat pumps or log burners you can get ducted systems which can take the heat from one room and disperse it to other rooms. This actually works well with log burners which tend to make one room too hot and all the others too cold. Not so good for heat pumps as they are specced for the volume of air they have to heat e.g. the size of the room that they are in, so you need a bigger one if you want to heat more rooms with it.

Another method used which is 'central heating' is gas ducted heating system where gas is burnt to produce heat which is ducted to the various living areas, these seem to be very common in new houses.

Ian

[peebles16]

I have to say that anything I post relating to keeping warm should be taken with a big pinch of salt as am complete wuss and hate being even a wee bit cold :no This morning for instance I had several layers on whilst OH was in shorts and t-shirt and wee one in a pair of socks (that's 3 year old boys for you :D )

Our rental is practically brand new with insulation and double glazing and one heat pump. It doesn't heat the whole house but if it was our house I would put another one near the back of the house and think that would be good enough :yes

Karenx

[zardell]

Just to say that this thread has been resurrected from 12 months ago and as you probably know by now we've moved, but nevertheless, I'll tell you the end result.

It transpired that the heat pump was not big enough to do the job. It was a 4.(something) and an 8.(something) was the required size.

You can tell I understand these things can't you !!!!!!!

Anyhow, we ended up buying a gas fire and it was fantastic.

I have to say and this is purely from a personal perspective, that IMO any form of 'hot air' heating is OK whilst it's running. The second it goes off the room begins to feel colder.

Nothing to do with the lack of insulation in our case, although lets face it, double glazing would be advantageous in any house, but even with the gas ducted 'central heating' we have now, albeit lovely and toasty warm, I don't find it as efficient at maintaining the heat in the rooms as I believe I would if there were radiators.

And I miss my fireplace!!

Julie

xx

[suebeenz]

Hi Julie,

Glad you're keeping warm! Makes sense that heat smaller heat pump wouldn't have done the job right. I recently got a heat pump installed, and love it so far. Decided to go with the ducted approach, so there are vents in every room. Depending how cold your climate is where you live, gas could actually be the most cost effective choice. I've read about heating solutions that use gas when it's cold, and switch to the heat pump once outside warms up enough. Cool!

Btw, personally i like the idea of forced air heating (whether be from gas or heat pump), just to get the air moving around the house. Think it's good for moisture reasons. Having said that, I like the idea of heated floors for the next house. :-)

[suebeenz]

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