Heating - Aircon vs Oil heater

Lairzone on 18/06/2013 - 20:06

Hi Guys,

My baby is waking up at night because of the cold, and for those who have kids, they'll know this sucks… We got an oil heater for the older kid when she started doing the same and it made all the difference - but at a massive cost.

So I have this oil heater (7 fins) and my place has ducted aircon (not an inverter unit). The aircon can heat only the bedrooms, but the thermostat is in the main room and therefore it goes full tilt if the main room is not being warmed. The bedroom to heat is about 15m^2. Both devices have timer capabilities (and I would look to set it from 4am to 7am). Actually, the aircon gets turned on in the morning anyway, so I wouldn't have it stop automatically.

What do you guys think will be cheaper to run - an oil heater (in a room probably too big for it), or the aircon?

Electrical & Electronics

Comments

  • _Bruce_ on 18/06/2013 - 20:26

    Oil heater in one room which is kept closed is almost certainly better.

  • kwaker on 19/06/2013 - 11:11

    There would be ways to make heating more efficeient for the baby without having a heater running all night and the dangers of that. I know a firefighter and he has told me of his first hand account of heaters left on at night killing children.

    Heating a small space rather than the whole room. Wrap the cot and put a blanket over the top so the heat is not escaping. Warm it up with the heater and then turn it off and leave baby with a warm water bottle or warm wheat pack.

    Im sure google has some suggestions.

    • _Bruce_ on 19/06/2013 - 13:14

      Blanket over cot was strongly advised against my midwives I have talked to.

      • kwaker on 20/06/2013 - 22:24

        And heaters weren't?

        • airzone on 24/06/2013 - 10:25

          You sure the advice doesn't relate directly to a gas heater? An unflued gas heater is dangerous for anyone to be left on overnight. Otherwise, setting the thermostat is tricky - it is easy to run it too warm and overheat the kid.

          Anyway, my baby is old enough to pull the blanket down, so can't consider this option.

        • kwaker on 25/06/2013 - 20:20

          No fires resulting from different circumstances. Ie clothes touch it faults etc

  • Somesh on 21/06/2013 - 09:40

    Definitely Oil heater ,
    Even my bills went up by 2.5 times but its worth as it related to Priceless children sleep.

  • airzone on 24/06/2013 - 10:21

    So I did a bit of research on this (like I should have in the first place) and have come up with the following:

    • Oil heaters, coil heaters, etc have a best case conversion rate of 1 unit of electricity to 1 unit of heat.
    • Aircon has an average conversion rate of 1 unit of electricity to 3 units of heat (but the newer ones can be as high as 5, old ones can be lower).

    Because, electric heaters will create heat from electricity, whereas an aircon will extract the heat from the outside air and pump it inside.

    Therefore, aircon is around 3 times more efficient.

    What is cheaper though? In my case, I have to run the aircon for the whole house. But factor in the duty cycle, input power to each, and the aircon should be lower by at least half. And I will have a warm lounge when I wake up.. I shall see when I get my next bill though..

    • _Bruce_ on 24/06/2013 - 12:52

      Be careful here. Yes the physics of the unit are such that the theoretic heat transfered may be 3-5 times than of the engergy used, but this does not translate directly to a third the energy use for heating a room, in much the same way as wifi speeds are not what they seem. Also the efficiency will decrease as the room/house becomes warmer which will not happen for the oil heater.

      Furthermore, depending on your insulation, the difference between heating one room and the whole house can be very large indeed. It will almost certainly outweigh the energy savings.

  • kwaker on 25/06/2013 - 20:16

    You could test it. Look at your metre run air con for a night then compare it to your other heater

    Its not just comparing output because its different rooms and different seals.

  • airzone on 15/08/2013 - 21:45

    To update everyone on what has happened:

    I chose to use my Aircon instead of the bar heater. I have my aircon set to 18 in the day, 17 at night. I would turn my AC off at night with a timer set to turn on at 4am (which is when I would have set the bar heater timer), except all the aircon zones are active.

    So I got my bill, and I was down 1kwh from the bill last year. Effectively the usage difference wasn't significant, but I had 2 bedrooms heated, and a warm lounge room when I woke up. So a win, I guess.

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