Should I Replace Ducted Heating System

Llongnt80 on 18/08/2023 - 10:38

I got a ducted heating system servicing today and they said there many issues:

  • Condensation drain had been leaking up in the roof for quite a while.
  • Found that PVC flue connection had also been leaking causing rust to form on top of machine plus in the fan chamber.
  • Inspected heat exchangers and found rust forming around them.
  • Done a carbon monoxide test which was 0ppm how ever due to the condition of the heater and for safety would recommend replacing the system.

I had a building inspector checking the house before this and they didn't report any issue related to the heating system.

Should I change it or not? New ducted system is not cheap.

Home & Garden

Comments

  • Muzeeb on 18/08/2023 - 10:45
    +7

    2 options:

    • Replace it now
    • Replace it when it eventually dies or you do.
    • HeWhoKnows on 21/08/2023 - 20:27

      Too quick again Muzeeb!
      There are more options…
      3rd option dont replace it at all if you dont use it
      4th option Investigate other heating or ac options

  • AngoraFish on 18/08/2023 - 10:47
    +1

    Building inspector reports are rarely worth the paper they're written on. If they spent more than 30 minutes poking around you got lucky.

    Carbon monoxide shouldn't be an issue, because the system is outside of your house. If you did have carbon monoxide issues there would be something very seriously going wrong.

    In my view that's a lot of fiddling around and probably not likely to be cost effective repairs compared to just going for a new system - you'd be keeping the system going with duct tape and elastic bands, essentially.

    In the end, though, that's all fixable so it depends a bit on how accessible the various bits are and how much rust you're actually seeing.

    edit: I agree with AustriaBargain, multiple split systems would be the way to go if your house can accommodate. Ducted heating systems are just a bundle of problems, and extra-expensive to run.

    • longnt80 on 18/08/2023 - 12:16
      +1

      tbf, the building inspection didn't include heating system since they're not electrician.

      • AngoraFish on 18/08/2023 - 19:00
        +8

        …or a plumber, or a structural engineer, or anyone who knows how to use a ladder, or someone who is physically capable of brushing aside a few overhanging branches, or anyone who knows anything about construction other than by virtue of their ability to tick pro-forma boxes in a software package they purchased off the internet from someone who spent more money on boilerplate legal disclaimers than they did on programmers or getting advice from actual builders.

  • AustriaBargain on 18/08/2023 - 10:47
    +7

    I think a more modern solution is getting multiple split systems. How old is your ducted system? Your problems are mostly old pipes which doesn't sound like a bit issue. Is it relatively new, or is it basically end of life?

    • longnt80 on 18/08/2023 - 11:00
      +1

      It is old (10 year now)

  • Some Human on 18/08/2023 - 10:48
    +6

    Just get a couple of split systems. You'll save more in the long run. Gas ducted heating is crazy expensive.

    • AustriaBargain on 18/08/2023 - 11:14

      Yes heat pumps are very efficient. You can get heat pump ducted, but if OPs is gas then their efficiency is 1:1; 1 gas burned gives him 1 unit of heat.

      • outlander on 18/08/2023 - 12:49
        +4

        To expand on that, prices at the moment seem to be 3c per mj for gas. A kWh is 3.6 mj, so natural gas is just over 10c for the equivalent heat of 1 kWh. But due to gas causing poisonois fumes when burnt, it has to be vented, lowering the efficiency. Most figures I've seen say you get around 80% efficiency burning gas. Which means to get the equivalent heat to 1kWh, you have to spend 12.5c on gas

        Electricity is a bit expensive at the moment. It seems to be about 30c a kWh for most people. If that were the end of it, gas would be the clear winner. But air conditioners are able to steal heat from outside, giving you more heat per kWh consumed. Typical efficiencies for air conditioners are as low as 3:1, but the newer smaller ones go above 5. At 3:1, you're paying 10c per kWh of heat, which is cheaper than gas. But at 5:1, you pay only 6c per kWh for heat, half the price of gas.

        So it's a no brainer to dump gas for reverse cycle air conditioners just on running costs alone. Then you look at the daily service charges of $350 a year you could save by not having gas connected, lower risk of fire and breathing concerns, and air conditioners are the clear winner

        • AustriaBargain on 18/08/2023 - 13:23
          +2

          And solar further makes reverse cycle ACs more attractive, even if you don't have a battery there's still a lot of daylight hours in each day.

          • jv on 18/08/2023 - 15:57
            +1

            @AustriaBargain:

            even if you don't have a battery there's still a lot of daylight hours in each day.

            Nights are when it's coldest though…

            • AustriaBargain on 18/08/2023 - 16:02
              +2

              @jv: Running it for free in the day, or for the equal of the 5c feed in tariff, will help keep the house warm by night. And it'll keep your cats happy.

              • jv on 18/08/2023 - 16:11
                +1

                @AustriaBargain:

                Running it for free in the day

                Don't need it during the day, need it at night when it gets cold.

                will help keep the house warm by night

                House will be cold within 30 mins of heating been turned off.

                • [Deactivated] on 18/08/2023 - 16:12
                  +1

                  @jv: Do you sleep with the a/c on in winter?

                  • jv on 18/08/2023 - 16:13

                    @[Deactivated]:

                    Do you sleep with the a/c on in winter?

                    The heating.

                    • [Deactivated] on 18/08/2023 - 16:17

                      @jv: What's the temp overnight?

                      • jv on 18/08/2023 - 16:20

                        @[Deactivated]: probably down to around 15°C inside

                        • [Deactivated] on 18/08/2023 - 16:31
                          +3

                          @jv: You don't need heating - you need a better doona

                          • AustriaBargain on 18/08/2023 - 16:38

                            @[Deactivated]: jv obviously likes sleeping in the nude without any sheets or blankets, with the windows wide open

                            • [Deactivated] on 18/08/2023 - 16:44

                              @AustriaBargain: So that's the reason the sleeping exhibitionist requires overnight heating

                • xylarr on 19/08/2023 - 11:49
                  +2

                  @jv: If the house is cold within 30 minutes of the heating being turned off, there is some very serious insulation problems. That would be where the best money is spent first.

  • mreddie on 18/08/2023 - 11:00
    +7

    Can't stand split systems, don't care my costs… love my ducted heating.

    • JimmyF on 18/08/2023 - 12:34
      +6

      Get a ducted reverse cycle then.

      • jv on 18/08/2023 - 15:58

        Can you use the same floor ducts for reverse cycle?

        • JIMB0 on 18/08/2023 - 16:36

          No

          • jv on 18/08/2023 - 16:49

            @JIMB0: Why not?

          • JIMB0 on 18/08/2023 - 17:16
            +1

            @JIMB0: They're too small for airconditioning

        • ZloyKrys on 19/08/2023 - 09:44
          +2

          You'll need new ductwork and new slightly larger floor registers but can put in place of gas gucted underfloors

  • djsweet on 18/08/2023 - 11:09
    +2

    How would a building inspector know if the heating system has issues? Anyway. If it really is a safety issue or its costing you a fortune to run, replace now. Otherwise just wait till it dies. The longer you wait the more you will save (provided it isn't burning electricity like a rabid toaster).

    • JimmyF on 18/08/2023 - 12:35
      +1

      Based on the leaking drain and rusted outside unit, the inspector should have spotted them.

      • reactor-au on 19/08/2023 - 07:44

        He said it is in the roof, do building inspectors even go up into the roof?

        • JimmyF on 19/08/2023 - 10:15

          It's not really a building inspection if they don't look in the roof or under the floor if you have those areas. I agree most inspections are near worthless and not worth the paper they are written on if they miss anything, but the decent ones do check all these areas out.

  • franco cozzo on 18/08/2023 - 11:12
    -3

    writing is on the wall for gas as a viable fuel according to our overlords….give it several years and theyll ban it outright, not just on new builds & the cost will be so prohibitive that it wont even be a viable option for the majority

    and it doesnt matter if youre not in vic….theyll be coming for your gas appliances in all the states guaranteed

  • lachhelix on 18/08/2023 - 11:43
    +7

    Done a carbon monoxide test which was 0ppm how ever due to the condition of the heater and for safety would recommend replacing the system

    Let me guess - the "servicing" company conveniently also offers installation of a new one for you

    • hothed on 18/08/2023 - 12:11
      +2

      This ^^^
      No leaking gas, so it is safe to use. Keep use it until it dies, then replace with aircon(heat pump) in 5 years time.

      You can get aircon ducted or split systems for each room. Bonus is they do cooling and heating.

    • JIMB0 on 18/08/2023 - 16:39
      +1

      They only know how to vacuum an old unit and shoddily install a new system. Diagnosing and repairing an old unit requires too much in the way of knowledge and smarts.

  • azero on 18/08/2023 - 11:43
    +3

    I replaced a gas ducted with a daikin reverse cycle ducted system about 6 months ago. It does cost a lot (5k vs 15k), but I didn't really like gas heating.

    The ac is actually cheaper to run than gas. But I did notice that it can't heat the house as quickly as the gas in 2 degree Melbourne mornings.

    CO can leak into the house from the heater. It is just in the ceiling and not outside.

    Split systems will be cheaper to both run and install, but I can't stand them hanging in both inside and outside the house!

  • JimmyF on 18/08/2023 - 12:36
    +2

    I got a ducted heating system servicing today and they said there many issues:

    All easy things to fix looking at the items. Rust isn't the end of the world, metal items rust. So you'll have to review if it is just surface rust or rusted through.

    Done a carbon monoxide test which was 0ppm

    So nothing has rusted through.

    Fix the exhaust, fix the drain, you'll be good to go.

    • mskeggs on 18/08/2023 - 15:15
      +3

      Add a $30 CO monitor in the room below the heater for peace of mind.

      • JimmyF on 18/08/2023 - 15:33
        +1

        Agreed. Everyone should have one if you have any gas appliances like heaters or stove.

  • 2jzzzz on 18/08/2023 - 13:50
    +1

    Splits and run off electricity. Better to put money into solar

  • jv on 18/08/2023 - 15:54

    New ducted system is not cheap.

    How much?

    • longnt80 on 18/08/2023 - 22:01

      They quoted $4700 total (the unit and labor cost)

  • Dorge on 18/08/2023 - 18:39
    +1

    Fix the condensation issues. 10 years is way to short for a ducted system to be replaced.

    Sounds like the service person is fishing for extra work "carbon monoxide test which was 0ppm" so it's safe, good to fix, service every X amount of years. I'd likely get a separate, recommended worker to do the works.

    Unless you have solar, with all for elec plants closing down. I would not place bets on switching from gas to elec being cheaper in the future.

  • JIMB0 on 18/08/2023 - 22:49

    I believe these units have a combustion fan sucking the combustion gases through the heat exchanger keeping them at a lower pressure than the air passing over the heat exchanger. This way if there was a leak in the heat exchanger you wouldn't get carbon monoxide in your house. Then there's a few pressure switches that would trip if the pressure differential wasn't maintained for some reason.

  • jrvb42 on 19/08/2023 - 09:02

    So the building inspector found nothing (independent third party).
    A heating contractor found heaps of probs (they want to make money, yes?).
    Get another opinion.
    1. If problems are found, and they should have been found by the inspector - sue the inspector for the cost of replacement.
    2. If no problems are found, report the first heating contractor for attempted fraud - or get them to provide proof of the problems.

  • bbinc on 19/08/2023 - 09:42

    Longnt80
    Found that PVC flue connection had also been leaking causing rust to form on top of machine plus in the fan chamber.

    Since when can PVC be used for a gas flue? Or did the inspection people make that up?

    • JIMB0 on 19/08/2023 - 11:35
      +1

      It's a high efficiency unit. They extract so much heat from the combustion products that it causes condensation, hence the considerate drain. PVC is required as the condensate is highly corrosive.

  • LFO on 20/08/2023 - 12:04
    +2

    "I had a building inspector checking the house before this and …"

    Just to clarify this misconception.

    Building inspectors inspect and certify issues with the building, not its functionality.

    I had a similar conundrum with one regarding those compulsory fire/smoke detectors/alarms. Their responsibility is to check "they are visually there" and NOT to test them for proper functioning. As told: "we are building inspectors not smoke alarms inspectors/specialists.

    Also, for example, they will check if humidity in walls is excessive due to, for example, a leaking roof. Will not certify the roof doesn't leak, will certify the humidity content when check was "as expected".
    Same with electrical wiring, will check the existence (or not) of safety switches, not its functionality.

    They will detect building faults or rather, non compliance due to (usually) self-made jobs.

    • reactor-au on 21/08/2023 - 10:19

      That raises a good point, should a gas and electrical inspection not be part of the presale to ensure the property is safe?

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