# Forum Home Renovation Heating & Cooling  recommend a ducted gas heating unit for my house

## wozzzzza

got a 5 bedroom house, 180sqm living area, need 8 outlets, looking at the bonaire natural gas B21 unit. http://www.bonaire.com.au/gasheating...fications.aspx
this is about $1950 for the unit after a phone call to one place.
anyone recommend me a better system or any other advice about getting ducted gas heating? i dont know much about it.

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## Terrian

> got a 5 bedroom house, 180sqm living area, need 8 outlets, looking at the bonaire natural gas B21 unit. http://www.bonaire.com.au/gasheating...fications.aspx
> this is about $1950 for the unit after a phone call to one place.
> anyone recommend me a better system or any other advice about getting ducted gas heating? i dont know much about it.

  we were looking at bonaire, but went for a Brivis HE20E, 5.1star, we have 9 outlets, so far we are more than pleased with it, was about $3800 installed

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## dhall

> we were looking at bonaire, but went for a Brivis HE20E, 5.1star, we have 9 outlets, so far we are more than pleased with it, was about $3800 installed

  I am also looking at a ducted heating system.
Any ideas on the running costs.  The installer who I got a quote from had a quess that a 45kg lpg bottle would last about a month.  But I went to confirm this with the NZ dealers for brivis and was told that a bottle would only last about 7-8 days, running 6 hours per day. I queried this and was told the 7-8 days was correct.   But a heating cost of $2.90 per hour or a about 1 litre of lpg hour seems a little excessive?
Can you shine any light on the subject.  I was looking at the HE30i.

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## Smurf

The 7-8 days figure sounds more likely. 
But if you can tell me what the gas consumption figures (either MJ or expressed as KW) are then I'm more than happy to calculate exact hourly consumption for you - it's not as hard as it sounds.  :Smilie:

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## dhall

The HE30i system is meant to be a 30kw system, with a 5.5 energy star rating.
Surely the system would not be running at full steam ahead all the time it was on.  Wouldn't the system be running at or near full power when it was initially heating the house and then switch on and off as and when the inside temperature moved out of the preset parameters?

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## president_ltd

have a HE30e here (external unit - HE30i is internal).
only time it goes into a 'turbo air mode' is if there is a significant difference in temperature between setpoint & current temp.  e.g. if we've been away for the weekend with it off, maybe its 15 deg C inside the house and we set it for 20C. 
however, it does that for perhaps 10 minutes (if that) as it gets closer to the setpoint it adjusts itself accordingly. 
very happy with the unit.

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## craig hewitt

> I am also looking at a ducted heating system.
> Any ideas on the running costs.  The installer who I got a quote from had a quess that a 45kg lpg bottle would last about a month.  But I went to confirm this with the NZ dealers for brivis and was told that a bottle would only last about 7-8 days, running 6 hours per day. I queried this and was told the 7-8 days was correct.   But a heating cost of $2.90 per hour or a about 1 litre of lpg hour seems a little excessive?
> Can you shine any light on the subject.  I was looking at the HE30i.

  1 Lt of LPG contains 25.3 mj, a HE30I has the ability of consuming 120mj/hour to have an heat out put of 30kw so this unit could consume 5 lt an hour of LPG. our friends used a 300lt gas tank in under two weeks using a 120mj or 30kw heater ducted gas heater, not shore of brand, but it had a 5 star rating, thought the unit has broken down. Rude shock when they found it had ran out gas. 
Not shore how much LPG costs compared to Heating oil but heating oil has a higher Mj than LPG, 36.5 mj per lt. Thats 30% more but is oil 30% dearer than LPG.

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## craig hewitt

> got a 5 bedroom house, 180sqm living area, need 8 outlets, looking at the bonaire natural gas B21 unit. 5 Star ducted gas heating specifications
> this is about $1950 for the unit after a phone call to one place.
> anyone recommend me a better system or any other advice about getting ducted gas heating? i dont know much about it.

  The Brives HE20I is a 20kw and will use 85mj of gas to produce that heat. Natral gas cost about 1.9866 cents per mj/h so 85 mj gas unit running at 100% capacity will cost $1.69 to run for 1 hour. 
A Daikin FDYQ180 inverter with a rated capacity of 20kw heating output will consume 5.63kw of electricity with electricty cost at 15.246 cents per kw/h it would cost $0.86 for 1 hour running at its rated capacity.  
Even when it gets down to -5 the Daikin FDYQ180 has 19.8kw of heat with a input power of around 6.0kw or around $0.91 cents per hour. 
Gas is not as cheep as they make out, but it is cheep to put in, but you pay for it in running costs in the end.  
and they slug you about $200.00 a year just to have it connected to your a home.

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## Smurf

These costs are for Tasmania (specifically Hobart) but could be scaled to reflect your local fuel prices. 
Electricity (fan heater, must be hard wired) = 12.558 cents per kWh on the discount heating tariff (something that is pretty much unique to Tasmania). 
Electricity (fan heater, portable) = 20.823 cents per kWh on the normal household electricity tariff. 
Electricity (off-peak) = 10.11 cents / kWh on the extended hours rate (best for heating) or 9.522 cents / kWh on the shorter hours rate. 
Electricity (heat pump (reverse cycle A/C) = about 4.2 cents / kWh on the disount heating rate, or 6.9 cents / kWh if connected to the normal tariff. 
LPG at $112 per 45kg cylinder = 22.4 cents / kWh assuming 80% efficiency of the appliance. It works out at 17.9 cents / kWh for an unflued heater, although these are not recommended for household use in cold climates due to potential build-up of fumes. 
Natural gas at 1.99 cents / MJ = 8.95 cents / kWh assuming 80% efficiency. It works out at 7.16 cents / kWh for unflued heaters but see note above regarding unflued gas heating. 
Heating oil at $1.40 per litre delivered = 19.7 cents / kWh assuming 70% efficiency of an old oil-fired heater (new oil-fired heaters haven't been commonly sold here for 30 years, so all those in use will be fairly old now). About 14 cents / kWh for the unflued units which are intended for industrial use (workshops etc). 
Kerosene at $1.80 per litre plus your cost of getting to the only outlet that sells it from a pump (in Sandy Bay, an inner suburb) = about 18 cents per kWh. These heaters are smelly and potentially dangerous however - good for the shed but not for the lounge room in my opinion. 
Wood pellets at $500 per tonne delivered = 11.6 cents / kWh based on 83% appliance efficiency. 
Ordinary firewood at $130 per tonne delivered (cheaper if bought over Summer) = 4.8 cents per kWh used in a 60% efficient slow combustion heater (the actual figure for a very popular model here is 61% but some of these heaters are somewhat more efficient - around 70% for the best ones). There will however be some wasted heat since you can't turn a wood fire on and off like you can with other fuels, for example when going out or going to bed. 
Based on all of that, I would suggest that the options are as follows: 
Cheapest: 
Heat pump (reverse cycle A/C). Wood if you don't mind the hassle of dealing with firewood.  
Mid-price: 
Electric fan heater on discount rate. Electric off-peak. Natural gas. Wood pellets. 
Expensive: 
Electric heaters on normal tariff. LPG. Heating oil. Kerosene. 
As I said, check fuel prices locally as the situation we have here in Tasmania, particularly with regard to the disount electricity for heating, is unusual. Also firewood is cheap here compared to many other urban locations.

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