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Topic # 65688 5-Aug-2010 19:48
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i'm looking at putting in a ducted (underfloor) gas central heating system.

a couple of the systems i'm currently looking at are from Brivis and Braemar.

Does anyone have a system installed, or have experience with these systems and have an opinion they'd like to share?




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  Reply # 363899 5-Aug-2010 20:44
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Unless you own your own gas field or have a rather large income I would advise against using gas heating.

We are building a house at the moment and are thinking of installing gas hot water. The gas salespeople I have spoken to told me to steer clear of gas heating as it is very expensive compared to other options. These guys actually sell gas heating units so for hem to say that there must be something in it.

Several builders we spoke to have said the same thing, don't touch it.



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  Reply # 363930 5-Aug-2010 21:33
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marmel: Unless you own your own gas field or have a rather large income I would advise against using gas heating.

We are building a house at the moment and are thinking of installing gas hot water. The gas salespeople I have spoken to told me to steer clear of gas heating as it is very expensive compared to other options. These guys actually sell gas heating units so for hem to say that there must be something in it.

Several builders we spoke to have said the same thing, don't touch it.


gas heating is oone of the cheapest options at 6c per kWh - assuming you have reticulated gas.  If you use LPG bottles then you're getting shafted on price.  if you're connecting reticulated gas for instant or gas heated hot water, then you might as well use it for other things too as you're already paying the daily charge.

one of the benefits of gas is also that you can switch on a system and have the entire house heated to a nice level in about 20 minutes or so.  if you use a heat pump, night store or wood heating option you need a bit more time before the place is cosy.... by leaving the gas central *off* most of the time and only using it when you need it, it should be cheaper.






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  Reply # 363931 5-Aug-2010 21:36
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marmel: The gas salespeople I have spoken to told me to steer clear of gas heating as it is very expensive compared to other options. These guys actually sell gas heating units so for hem to say that there must be something in it.


i've also noticed that gas salespeople will sell you $7000 of gas heaters to heat two rooms, or $12,000 if you want one to be a pretty fireplace version, and hope that you dont get a quote for central heating as it doesnt turn out that much more expensive.  rrp costs for a central gas system seem to range from around $8,000 to $12,000.  make sure you're not being fed a line...




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  Reply # 364056 6-Aug-2010 09:30
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Regs: gas heating is oone of the cheapest options
I totally agree.

I did some calcs for our new house, well not new but we just moved into it!  It has gas hot water and had an old school gas wall heater.  I looked at costs for supply and install of gas vs heat pump and found them to be very similar.  Roughly $2,200 for gas unit and $2,800 for heat pump.  Install was similar.

Running costs were very similar I found and I really would like to see how consumer etc keep producing their running cost charts showing gas to be so expensive.  On an actual unit cost of energy to heat gas comes out cheaper in our case than a heat pump.  This would be skewed of course if you included the gas supply line charge, but as Regs mentioned, for a home that already pays this for water heating etc then it doesn't really feature in heating energy costs.

Flued gas heaters are boringly always only 85% efficient when it burns, but it's this constantly regardless of outside temperature.  Heatpumps can be up to 300% efficient, but the electricity unit cost is more than 3 times that of gas.  When it's cold outside, ie when you need it running the hardest, the efficiency can dramatically drop to 150% efficient, and you are then paying a huge amount for heating.

So yeah, gas is inefficient, but it's cheap as.
Electricity is expensive compared to gas, so even very efficient devices work out at very similar costs to run.  Factor in the loss of efficiency when it's 15 - 20 degrees colder outside than in and it's not as clear cut as all the TV marketing makes out.

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  Reply # 364061 6-Aug-2010 09:33
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I went through the same process, liked the idea of Gas and then went with heatpumps.

Even two of the gas guys who game me quotes asked why I wasn't getting a heatpump?




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  Reply # 364065 6-Aug-2010 09:37
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marmel: We are building a house at the moment and are thinking of installing gas hot water.
If you are building from new there there are probably better technologies out now like solar, or even some use of heat pumps to heat hot water.  Depending on where you are, if you are having a log fire installed then it would really pay to shuffle the design to put the fire by the hot water cylinder, to allow for a wet back.

Gas works well and doesn't rely on electricity but to justify the extra gas line charge you'd probably want to include other items in your house, ie heating or cooking etc.  Otherwise yes the line charge does add up.  Gas has a much cheaper unit cost than electricity, so it's economical where you will be doing a large amount of work, like a large hot water cylinder for a big family home.  Like everything though there are pros and cons to all options.

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  Reply # 364067 6-Aug-2010 09:41
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I have just come back from Germany and virtually every house has a central gas heating unit (although with old school wall radiators). Its definitely the way to go there because heat pumps don't work in the cold although they probably are fine in most of NZ. The other advantage of heat pumps remember is AC in the summer.





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  Reply # 364069 6-Aug-2010 09:43
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Jaxson:
marmel: We are building a house at the moment and are thinking of installing gas hot water.
If you are building from new there there are probably better technologies out now like solar, or even some use of heat pumps to heat hot water.? Depending on where you are, if you are having a log fire installed then it would really pay to shuffle the design to put the fire by the hot water cylinder, to allow for a wet back.

Gas works well and doesn't rely on electricity but to justify the extra gas line charge you'd probably want to include other items in your house, ie heating or cooking etc.? Otherwise yes the line charge does add up.? Gas has a much cheaper unit cost than electricity, so it's economical where you will be doing a large amount of work, like a large hot water cylinder for a big family home.? Like everything though there are pros and cons to all options.


There won't be a gas line charge, there are no gas lines in the deep south.

We are probably going with a gas hob as well so it would be used for that also.

As far as I am aware it is now illegal to install a wetback system on a log fire (in Southland anyway) as the wetback system draws heat out of the firebox which in turn means the fire does not burn as cleanly.

You also can't buy a log fire now (and have it signed off by the council) unless it is one of the clean burning models which do not stay in overnight so that pretty much rules that out.

Solar heating is still not efficient when you take into account the purchase costs and the amount of sunlight we get in this area, I think this technology still has another 5-10 years before it becomes really attractive.

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  Reply # 364073 6-Aug-2010 09:45
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Zeon: I have just come back from Germany and virtually every house has a central gas heating unit (although with old school wall radiators). Its definitely the way to go there because heat pumps don't work in the cold although they probably are fine in most of NZ. The other advantage of heat pumps remember is AC in the summer.


Not sure how much of an 'advantage' having AC is in the Summer as all it will mean is a bill you never had previously.

There's a big difference between heatpumps and hot water heat pumps that are used alongside radiators

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  Reply # 364085 6-Aug-2010 10:07
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marmel: in the deep south.

You will have limited options then aye.
Burning stuff gives a lot of heat, but is very manual.
Using electricity will cost you a lot, and you'll need to buy the real expensive heat pump variants to guarantee they will work close to and below zero deg.  I'd seriously be checking the real world effeciencies at those lower temperatures as it could cost you a bomb if they start backing off from their 300% TV claims.
Gas means bottles I take it in your case?  Regs made mention above that the price may be far more for gas in this delivery type, I can't comment on that.
Can say gas cooking is awesome, but that's probably not a strong enough argument to base everything on though! Good luck with your new house, sounds cool.



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  Reply # 364134 6-Aug-2010 11:19
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langers1972:
Zeon: The other advantage of heat pumps remember is AC in the summer.


Not sure how much of an 'advantage' having AC is in the Summer as all it will mean is a bill you never had previously.

There's a big difference between heatpumps and hot water heat pumps that are used alongside radiators


yeah, no ability to turn on AC cooling is a plus in my case.  electricity bills tend to skyrocket with them.  if its there, you tend to use it.  We dont really need it in NZ - open some windows!

If you're desperate for cooling, there is also the evaporative cooling technology that can be added on to gas systems, but i dont need that.

For a new build with a concrete pad, i'd probably opt for something like in-floor water heating.   In a 90 year old bungalow, you're somewhat limited.




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  Reply # 364136 6-Aug-2010 11:25
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so, back on topic, no-one has GAS central heating installed?




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Reply # 364144 6-Aug-2010 11:43
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Yes, we do although it's not underfloor but radiators as I am English and that's what I know.

We had ducted underfloor heating in the UK and the one thing I would say about that is that it can be a bit of a dust blower when you first crank it up after a 'dormant' summer although that was an 80s design so they might have got around that.

I can't comment on the cost of running as we've only just moved into our rental so haven't had a bill as yet.

Equally important, if not more so, is your insulation as until that's sorted there's very little point in ploughing thousands into a heating system.

If you're in Wellington check out www.centralheating.co.nz as they are brilliant and James is English so won't act puzzled when you mention heating Smile

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  Reply # 364218 6-Aug-2010 13:18
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Regs: so, back on topic, no-one has GAS central heating installed?


I have a relative with it.  They have a system using ducting.  The cat loves to sit on the heating outlets.

Like heatpumps, people tend to use it a lot for the first month until they get the bill and then they cut back a little.

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  Reply # 364233 6-Aug-2010 13:42
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Yes we have a Brivis gas central heating installed in our large (230 sq.metre) 130 year old Itallianate villa in Wellington.

This house has a very high stud, sash widows and our lives would be a total misery without central heating. The install must be around 13 years old, we have been here for 5 years.

As we work from home the heating is on 24/7. It used to cost an arm and a leg to run until we took out the chimney, sealing the house better, insulated with pure wool ceiling insulation and installed draught stoppers around the ext. doors.

Since we did this 6 months ago our house is a lot warmer and our heating bill has dropped by a third. I'm not game to tell you our actual gas bill, but its not as bad as you would expect. Some people I know who have heat pumps installed in similar size homes pay nearly as much.

We simply could not live in this house without it.

Comparing to say heat pumps, a while back I had an installer come around to quote. He reckoned we would need about three heat pumps to heat our place in a similar way, so we stopped right there. Thats a big capital outlay in itself making change uneconomic.

The only pain with it is the controller is an old style non-backlit lcd screen which is installed in a dark corner making it very difficult to program. I know new ones are available but the cost does not warrant this upgrade.

I spoke to the ducting guy recently when he came around to reduct some of our heating system and he was very enthusiastic about the Braemar range.
I looked at this as it has better controllability over different household zones, but again the cap outlay would not be economic.

Hope this helps, by the way we also have gas water heating and cooking (which I love).

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