Thread: House Central Heating - Reverse Cycle Aircon

Hi Garrycol,

I'm not sure how it's done here ..... But make sure that whoever you end up selecting, they come around & measure it up properly. Include things like Night zone options & measuring the Return Air flow.

It's all a bit of a pain but you won't enjoy spending 15-20 K to do it all twice if it doesn't work how you want.

You'll have it for a long long time
Richard

Well I went window shopping yesterday to about 6 companies. They all recommended Daiken and depending on model needed cost will be between $8.5 and $11K. The cheaper price is for a 15kw single phase unit and the higher price is for a 20kw 3 phase unit (my current unit is only a 5hp, 5kw 3 phase unit). Prices were basically the same at all installers but obviously I will need quotes.

Interestingly they all said that even though these all have premium inverter technology these units still take a while to provide heat when turned on in very cold consitions - hence they are designed to be on all the time which I do not want.

I don't have gas at the moment but I also asked about it - $5k but a gas unit is a lot more expensive to run and the price of gas is going up - will also have to continue to pay the gas supply and admin fees in summer when the heater and gas is not being used. To get gas to my house would be another $500-$1k.

Looks like it is time to see if I have any personal contributions in my super fund before I freeze - though the little fan heater does a great job.

If anyone has any personal experiences please let me know.

Cheers

Garry

HI Garry,

I think that maybe they weren't explaining it properly .......
The logic behind leaving it on all true time is that the Walls, furniture, Carpet, ceilings etc, etc all "Soak" up heat.
If you leave it running, everything in the zone is eventually heated & de-humidified meaning that it doesn't need to be done again & the Unit isn't working as hard all the time.

You can still choose to switch it on & off manually or even better, you can program the timer & thermostat so it only runs when you're home.
EG start at 15 Deg & turn off at 21 Deg. Start at 17:00 & stop at 06:00 etc.
If you're looking at a unit of that size, I'd go 3 Phase if you can. It'll provide better balance for your power supply Billing.

Richard

I have lived a couple of times in Melbourne both in rented townhouse and own home. The townhouse had a bovis ( spelling ) buffalo underfloor gas heating system which was relatively quiet and very effective.It was run under the floor with outlets in each room. the house had ducted heating via a burner in the ceiling with outlets in each room. This system was marginal as i believe it had been originally installed prior to an extension being done and they may have just bumped the fan airflow.

Both systems were thermostat controlled and we turned it down overnight then up in the morning. main problem was with the ceiling mounted system sounding like a B707 on takoff power when the fan kicked in, usually at 0300 hours.

We also lived in Orange for 3 years with ducted heating in the front of the house and and a wall furnace in the back. both worked well.

Depending on wether you need cooling in summer I would be seriously looking at hydronic heating with a high efficiency boiler. warm and quiet. Electrickery is going to get much more expensive and gas although rising will be better for heating.

don't believe reverse cycle works well below 5C and tends to ice up. positioning of the return air grill is critical both for noise and heat distribution.

If you can score a good wood supply I would go with a Coonara tile fire. Had one in Camden and it was the best solution of the lot. They have a duct available that can draw air from a remote part of the house which is very good for heat distribution with a 3 speed fan. pretty cost effective and just nice to live with.

My preferred solution for a house we were considering near Cooma was for a coal fired boiler and hydronic. Mackenzie boilers in NZ make a very good unit that has been sold into the Bathurst district. They also have a cost comparison model on their website. Coal boilers Dunedin, Coal hoppers manufacturers Christchurch

hope this helps.

Originally Posted by kiwirich

I think that maybe they weren't explaining it properly .......
The logic behind leaving it on all true time is that the Walls, furniture, Carpet, ceilings etc, etc all "Soak" up heat.
If you leave it running, everything in the zone is eventually heated & de-humidified meaning that it doesn't need to be done again & the Unit isn't working as hard all the time.

You can still choose to switch it on & off manually or even better, you can program the timer & thermostat so it only runs when you're home.
EG start at 15 Deg & turn off at 21 Deg. Start at 17:00 & stop at 06:00 etc.
If you're looking at a unit of that size, I'd go 3 Phase if you can. It'll provide better balance for your power supply Billing.

Richard

Thanks Richard - I would leave my current system on overnight but it makes such as racket and it lives (suspended) under my bedroom floor giving me a cheap thrill when it runs.

I know of the issues of a/c in cold - my system has electric boosters but they have been disconnected because of the fire danger. I understood that the new high powered inverter systems were far better - I was just surprised that they took a while to warm up that was all.

Cheers

Garry

I would also look at Mitsubishi electric,we use it in preference to Daikin.

But your temperatures are a lot different than ours here,we only need heating for a few weeks a year.

The modern units are very good,extremely quiet,but as they are full of electronics,make sure you do your best to keep the geckos,rats,etc out of the units or you will have issues that may not be covered by the manufactures 5 yr warranty.

I would also go for the larger 3 phase unit.

Originally Posted by dromader driver

I don't believe reverse cycle works well below 5C and tends to ice up. positioning of the return air grill is critical both for noise and heat distribution.

If you can score a good wood supply I would go with a Coonara tile fire.

hope this helps.

Thanks for all those comments - apparently the new reverse cycle systems work well below zero but just take a while to build up heat.

When I first moved down to Canberra it was impossible to go outside at night in winter and breathe - indeed wood heating is now banned in some suburbs, so wood is definitely not an option.

Thanks for the input - I appreciate it.

Garry

Pretty much all heat pumps are rated at 7c outside in heating mode. They can really plummet in efficiency and capacity add it gets colder.

I am running a 7kw output heat pump upstairs and a fire downstairs. Costing me about $2 a day to power it, averaging around 600w when I look. That's the great part about inverter models, they slow down to suit the load. A few good frosts here so far.