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Posted by Vance on December 7, 2006, 10:38 pm
>
>>
>>> wrote:
>>>
>>>>At -10C, which is also my design temp, my condensing gas furnace runs
>>>>for
>>>>20
>>>>mins every 2 hours to maintain a setpoint of 18C with a spread of .5C,
>>>>obviously it is theoretically oversized, however, if sized 'correctly'
>>>>it
>>>>would run continuously at -10C and use significantly more KWH's. Which
>>>>would
>>>>be the better scenario, almost continuous run times to improve comfort
>>>>at
>>>>the expense of higher electricity usage or the shorter cycles with less
>>>>wear
>>>>on the blower and draft inducer fan?
>>>>
>>>
>>> WRONG! If it were sized correctly, it would have longer run times
>>> using a smaller KW heater. Thus balancing out the electric
>>> consumption. It is always better to properly size a furnace.
>>> Bubba
>>
>>There are no heat strips in this application - gas only. A smaller furnace
>>would cost more to operate and maintain due to much longer run times. 20
>>min
>>run times are certainly not short cycling nor reducing the efficiency of
>>the
>>furnace.
>>
> Interesting how you "use significantly more KWH's" as you point out.
> KWH's would be Kilo-Watt-hours. Those would be electric numbers
> junior.
> A smaller furnace would NOT cost more to operated and maintain.
> 20 min run times per 2 HOURS at design temperature IS definately
> over-sized.
> You're an IDIOT and/or TROLL.
You are either uneducated, misinformed or both.
Let me expand on "Those would be electric numbers":
KWH is a standard symbol representing power usage usually in the form kWh
which is 1000 watts used for a period of 1 hour. If the smaller furnace has
a 1/2 HP motor drawing 4A it will consume 1452 kWh in a 6 month heating
season (4*120*24*30*6*.7/1000) with a 70% duty cycle whereas the larger
furnace will consume only 207 kWh with a 10% duty cycle. At 20cents/kWh the
difference will heat my home for 4 months. This does not even take into
consideration the inducer fan or increased wear and maintenance costs.
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