Browse Forums Heating, Cooling & Insulation 1 May 17, 2011 9:27 pm Hi, I am about to build a new 2 storey 330 sqm house in sydney. Where tempereatures go above 40c and lowest is about 5c. I have thought about getting the actron reverse cycle ducted aircon, or brivis gas ducted heating with addon cooling unit. With the skyrocketing power bills, is it worth getting the brivis system, or is the actron reverse cycle sufficient. I know the brivis solution will cost more but is more cheaper to run. But is the outlay "worth it", since sydney doesn't really get that cold but does get a lot hotter. I have always rented in sydney and am unsure which solution is better in the long run? Also... if I decide to go down the reverse cycle solution, and later discover that I really need the gas heater to lower the bills, can I simply replace the reverse cycle unit with a gas blower and use the ducts already there? Or will I need to replace all the ducts? My plans have been thrown array because the govt has gotten rid of the solar rebates etc... and now confused and unsure which route to go down... Re: gas ducted heating / reverse cycle aircon 2May 18, 2011 9:16 pm I see a few people reading this thread, but no responses... So I'll post my research and decision in case anyone else comes afterwards wondering that same question. I've decided to stick with actron ducted reverse cycle cooling. Reason: 1) According to a discussion with the manufacturer, the efficiencies of inverter means it is quite cheap to run. The amount of power going to it way less than the cooling / heating power coming out of it., ie 4 kw input equals about 16 kw cooling / heating output. These numbers are rough.... but the efficiency is substantial and not just something like 30%. This efficiency is again improved with upgrades to the ESP and ESP+ series. 2) I will only need 1 unit for both cooling and heating. 3) Actron allows me to upgrade to 8 zones, so I can heat / cool 1 room only. Handy for big houses. 4) According to the numbers at monoair: http://www.monaroair.com.au/product/rev ... ditioning/ 15KW Electric Heater Nominal Heating Capacity - 15KW Nominal Cooling Capacity - N/A Nominal Power Input on Heating - 15KW Running Cost at 15Kw heating capacity per Hour - $2.10 Model - LG B48AWYU362 Reverse Cycle Ducted Air Conditioner Nominal Heating Capacity - 15.8KW Nominal Cooling Capacity - 14.1KW Nominal Power Input on Heating - 4.8KW Running Cost at 15Kw heating capacity per Hour - 63¢ Model - Bonaire 5 star B15 Ducted Gas Heater Nominal Heating Capacity - 15KW Nominal Cooling Capacity - N/A Nominal Gas Input - 60 Mj/H Nominal power input - 0.5KW GAS Running Cost at 15Kw heating capacity per Hour - $1.14 Electric fan running Cost per Hour - 7¢ Running Cost total at 15Kw heating capacity per Hour - $1.21 The calculations are based on ActewAGL energy cost 2010 with Natural Gas at 1.9 ¢ Mj and Electricity at 14 ¢ per KW/h. With regards to the ducts be suitable for gas heating and cooling. No, the ducts are not the same. You will need to tell the gas installers to upgrade the ducts. So yes, natural gas is cheaper... and may heat a big house quicker... but the efficiencies of the inverter make reverse cycle running costs cheaper. I am not an expert in heating or cooling or represent any company. Just a sydney sider who managed to eat baked beans long enough to afford a house and wanted to get the most for my money. If have erred anywhere in my understanding, could any of the experts on here please correct me... Re: gas ducted heating / reverse cycle aircon 3May 18, 2011 9:45 pm well given the above calculation are only based on 14cents per kwatt we are not far off the mark. Also on my last bill I was paying 1.4 cents a Mj (which will probably go up for winter).
Re: gas ducted heating / reverse cycle aircon 6May 20, 2011 4:55 pm I am in the same position as you, deciding heating and cooling for my new place. I was thinking about going for GAS heating and add on reverse cycle cooling but reading this thread is making me want to get just the cooling unit which can do electric heating. But being in cold VIC, I will be using my heater MUCH more then my air cond. Also electricity prices are more like 19-20c per kwh down my way. Thanks for posting this up, let us know what you decide with. Re: gas ducted heating / reverse cycle aircon 7May 20, 2011 5:08 pm Hi we're in cold old Vic too. We're building a 2 storey house with living upstairs and we're going for a Daikin reverse cycle ducted inverter system. That's what was recommended to us as the inverter allows the system to fluctuate it's power according to its needs therefore reducing the overall running costs as this allows it run efficiently. Re: gas ducted heating / reverse cycle aircon 8May 25, 2011 10:41 pm I've decided that I will stick to RCAC because in sydney I would not be using the heater for longs periods of time. It is warmer here in sydney than in melbourne. I guess if you live in melbourne and will be leaving the heater on for long periods of time, then gas might be for you. You need to also weigh up the efficiencies of the unit, does gas allow you to variably set heater and blower speed to keep tempereatures constant? How many zones does it allow you to have? How many sensors will it have? Will you leaving it on most of the time to warm all the house only only certain parts of the house? I stuck with ACTRON RCAC because I will be upgrading it to support 8 zones and 8 sensors, so I can have it warm only 1 room. It will allow me to have different tempereatures for each room and vary the amount of heat / cooling going to each zone. I like this flexibilty. There are also questions about the type of heat genereated from gas and RCAC. Will the gas heater be in the roof, does it have a flue? Do you care? Also how efficient are the cooler add on units? Re: gas ducted heating / reverse cycle aircon 9May 26, 2011 10:31 pm The ever evolving question - which way to go.... Many, many options guys. Pick your priority (heat / cool or both) choose how much of your house you want to run at once (ultimately determines unit size) do this for both heating and cooling - if they are the same your options open up a little. If they are not then this will limit your choices. If you have a large house, do you have 3 phase power? Air conditioning is a very personal thing and the system should ultimately be designed around how you want to use it, regardless of type. Start there You get what you pay for! The unit normally clips into a metal plate screwed to the wall, either plate is not flush, or unit not hooked in and could be hanging from the pipes partly, either might… 2 15788 retail its around double the price of a similar sized actron/dakin system from memory, They are excellent systems though. But with how builder gouge on AC/heating, you… 4 13773 Hi all, sorting out the ducted air con for a 350sqm double story house. Does this placement sound reasonable to you? Also, I plan to have 6 zones I think. Living room… 0 0 |