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Community and Q&A

Mitsubishi MUZ-FH12NAH Pan Heater

CollieGuy | Posted in General Questions on

I’m wondering if anyone can confirm if the pan heater on the Mitsubishi MUZ-FH12NAH runs continuously when temperatures fall below a designated set point, or if it shuts off after the defrost cycle has ended (or shortly thereafter).

According to the Northeast Energy Efficiency Partnership, the control algorithm is as follows:

A.) Heat mode is selected. B.) The ambient temperature thermistor reads 32F or less for 5 minutes continuously. C.) The defrost thermistor reads 30.2F or less for 5 minutes. D.) Outdoor fan motor is turned ON.

If I understand this correctly, it runs whenever the outside ambient air temperature falls below 0°C and the outdoor fan is operational.  If so, by my calculation, that represents an additional energy demand of some 400 to 500 kWh per annum in our local climate.

As a point of comparison, the MUZ-FH12NA which does not have a pan heater has a HSPF rating of 12.5, whereas the MUZ-FH12NAH is rated at 11.5.  The Fujitsu 12RLS3Y HSPF rating is 14.0, and the 12RLSYH with pan heater clocks in at 13.8, so the performance penalty is notably higher with the Mitsu.

I sent an e-mail enquiry to Mitsubishi Canada’s Residential HVAC contact page asking for clarification but never received a reply.

Having done all that I can to reduce our home’s energy demands, I don’t want to waste energy needlessly, particularly when over half of the electricity in our province is generated through the burning of coal and petcoke, two of the filthiest fuels known to mankind.


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  1. Expert Member
    Dana Dorsett | | #1

    Only Mitsubishi can give the definitive answer on how the pan heater is controlled. Picking up the phone and chasing them verbally may be what it takes if they're not email-responsive.

    >"...over half of the electricity in our province is generated through the burning of coal and petcoke..."

    NS, is it?

    The offshore (and shore side) wind resource in NS is actually pretty good- better than most already developed offshore wind projects in Europe. There is at least a hope that some day in the next decade the coal / coke fired stuff can be turned off, if enough political pressure builds toward that end. The tidal power resource in the Bay of Fundy has promise too, but would likely take much more time to develop, at a higher lifecycle cost than offshore wind.

    1. CollieGuy | | #3

      Interestingly, this model doesn't qualify under Efficiency Maine's heat pump rebate programme, as it doesn't meet their minimum HSPF threshold of 12.0.

      That being the case, and given that Maine has just passed legislation calling for the installation of one hundred thousand heat pumps by 2025, I would be surprised if Mitsubishi would allow one of their premium models to be shutout of this market.

  2. CollieGuy | | #2

    Thanks, Dana. My installer has also inquired on my behalf but without success, so perhaps a call is in order as you suggest.

    Wind currently supplies just 18 per cent of Nova Scotia's needs but hopefully its share will grow more quickly going forward. Clearly we need to do better.

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