Advice: Not enough heat


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Old 09-11-15, 02:20 AM
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Advice: Not enough heat

Hi everyone,

I need some advice. The place where I live is not particularly cold. Winter temperatures are around -2Celsius;+2Celsius in the evening. Never below -2Celsius

I have a room with +-40m2 with a Mitsubishi inverter 12kbtu. Winter temperatures are never extreme, but in those few days with very cold nights the air con is not enough for the room. The machine is sufficient for 90% of winter, but there are always days when it is not enough.

The outdoor unit is close to the ground. I have a similar machine of 9kbtu in a 25m2 room with the external unit in the well ventilated attic and it is perfect every single day. I think the air con is being less efficient for being located close to the ground where the temperatures are lower.

Whar do you suggest:
1 ) move the outdoor unit to the attic (easy to do) and thus prevent lower temperatures and gaining efficiency
2 ) Buying a 18kbtu machine (I can use the old one in another room)
3 ) Buy another 12kbtu and install it on the other side of the room

Thank you in advance
 
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Old 09-11-15, 04:50 AM
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Different models produce more heat than others. I get beat on jobs all the time when people quote a model that doesn't heat well. I seriously doubt I can tell anything from your model # because you aren't in the US but we can try. Can you get the model of the outdoor unit?
 
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Old 09-11-15, 07:53 AM
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Thanks!
Here it goes a Mitsubishi Electric MUZ-HJ35VA. As I am in the process of buying another aircon for another room. what should I be looking for in terms of heating capacity, what is more relevant? I keeo seeing Mistubishi, Daikins... ... being sold in supermarkets and I wonder how efficient they are.


Thanks a million!
 
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Old 09-11-15, 08:17 AM
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I don't think heat pump is designed to handle that kind of cold temperature. My heat pump automatically shuts down and switch to gas heat at 5 degree Celsius. This of course depends on the size of the room, and how well the insulation you have.....(any of those 3 methods that you suggested will help)
 
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Old 09-11-15, 12:59 PM
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Well I cant find that model in my us guide. But here in the states the MUZ models normally produce more than there rated cooling BTU's down to 47 degrees. At 5 degrees most are just a touch above half capacity of cooling.
 
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Old 09-11-15, 03:09 PM
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I don't think heat pump is designed to handle that kind of cold temperature. My heat pump automatically shuts down and switch to gas heat at 5 degree Celsius.
They can go down further than that. A properly sized heat pump is good to around -23 c (-10F). Granted they have loooong running times at that low a temperature, but they're still producing heat at a better payoff than resistive heat.

The problem is too many people are sizing them for Summer, which makes them too small for Winter (you need more BTU's in the Winter). If your Summer size is 12000 btu then you should plan on doubling that for Winter temps.
 
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Old 09-12-15, 05:42 AM
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I never use the AC in the summer, just for winter. I have 4 units. 3 work fine and all are above ground, this is the only one with problems and it is close to the ground in a humid area. Thats I am was thinking on moving it.
 
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Old 09-12-15, 02:25 PM
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Are you sure this one is fully charged like the other 3 ? and produce same amount of heat ?
 
 

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