Mini Split SEER

[jimblu]

I live in the tropics, cooling only, average temperature 85-95 degrees. We had a cheap 9000 BTU 10 SEER mini split that corroded away after a few years as everything does on the ocean. It was replaced with an alleged 20 SEER inverter drive mini split. I keep accurate records as electricity is quite expensive here and the power consumed went from 5 KW per day to 3.5 KW per day, not insubstantial, but not cut in half either. Is this really the best I can expect, are the SEER ratings accurate under these conditions?

[mchild]

I live in the tropics, cooling only, average temperature 85-95 degrees. We had a cheap 9000 BTU 10 SEER mini split that corroded away after a few years as everything does on the ocean. It was replaced with an alleged 20 SEER inverter drive mini split. I keep accurate records as electricity is quite expensive here and the power consumed went from 5 KW per day to 3.5 KW per day, not insubstantial, but not cut in half either. Is this really the best I can expect, are the SEER ratings accurate under these conditions?

It looks like you have seen about a 30% reduction in your electric consumption. It can be assumed you use electricity for other things so the portion that was used for cooling is now down much more than the 30% your total electric consumption is down. That portion may be down 50%. Without knowing how much you were using for cooling before - and now after the installation of the new equipment, you won't completely understand the amount of reduction in electric consumption.

[jimblu]

Not an accurate assumption. I have graphing meters on the electric consumption of the air conditioner, and the temperature and humidity indoors and outside. 3.5/5 KW are what the air conditioner is/was using. We also meter the other air conditioners (4 more) and the rest of the house separately.

[ALComfortmaker]

It looks like you have seen about a 30% reduction in your electric consumption. It can be assumed you use electricity for other things so the portion that was used for cooling is now down much more than the 30% your total electric consumption is down. That portion may be down 50%. Without knowing how much you were using for cooling before - and now after the installation of the new equipment, you won't completely understand the amount of reduction in electric consumption.

good explanation-- many people see the 50% or whatever their particular system says the savings will be and expect this will cut their bill in half, but as you explained it reduces that portion of your usage that pertains to the hvac.

[mchild]

Not an accurate assumption. I have graphing meters on the electric consumption of the air conditioner, and the temperature and humidity indoors and outside. 3.5/5 KW are what the air conditioner is/was using. We also meter the other air conditioners (4 more) and the rest of the house separately.

It would have been good to have mentioned that to begin with. May want to have your installing contractor look over the installation and compare the energy usage of your operating system against the manufacturers specs. An improperly charged system can consume excess electricity.

[hvac n-j-near]

The “S” in SEER stands for seasonal which means the efficiency number is kind of an average of very hot weather and cooler weather (seasonal). The new unit may be much more efficient in cooler weather and only slightly more efficient in very hot weather like you have there. So you may not see an exact 50% reduction.

Also, I assume you use electricity for things other than cooling such as lights, cooking, etc. The A/C unit has no impact on these.

[ALComfortmaker]

It would have been good to have mentioned that to begin with. May want to have your installing contractor look over the installation and compare the energy usage of your operating system against the manufacturers specs. An improperly charged system can consume excess electricity.

Exactly, tell half the story and want the whole answer.

[jimblu]

[QUOTE=hvac n-j-near;9557382]The “S” in SEER stands for seasonal which means the efficiency number is kind of an average of very hot weather and cooler weather (seasonal). The new unit may be much more efficient in cooler weather and only slightly more efficient in very hot weather like you have there. So you may not see an exact 50% reduction.

Bingo. That was the question, does anyone really know from experience how SEER compares in the Tropics. I am seeing an equivalent by the numbers of a change from 10 SEER to 14 SEER, not what the numbers would imply on a change from 10 SEER to 20 SEER. I would change more of the units if the electrical use really could be cut in half.