Mitsubishi Heavy Industries Bronte Series

I recently purchased the 7.1 kW Brontë SRC71ZRA-W model instead of the 63 as our summers are getting unpredictably hotter, and the winters, your guess is as good as mine. No regrets in my decision as these units are very efficient and my family and self are very happy with the wise choice. I don’t need to worry about “will the home be cool enough during summer heatwave?” The difference, in my opinion, between your two models are the indoor units as they both use the same outdoor unit, and I think it could be cosmetic. My SRC71ZRA is probably more rectangular-ish than the DXK but whatever it is, you won’t go wrong with the Brontë 7.1kW SRC71ZRA. Just remember that they need to be serviced once every two years to keep them in good working condition, and if you are in Western Sydney, get your unit from Globalrez and insist on having his best installer put your unit up. Kind regards, Romeo Alfa

Thank you for your reply,

I have bought the MHI 6.3kW DRK21ZRA-W today for $1,628 (Northern Brisbane). Getting installed for $650 in two days.

While the 7.1kW woould certainly have done the job, according to the MHI Room Sizing Chart, the 6.3kW should be sufficient for my needs and in my circumstances (44sqm).

It is replacing a working 7.1kW system (Celestial) that was installed in December 2003. Yes, this is correct, it is 20 years old and it is still working! (it did stop working once when an Asian gecko fried a circuit board in the interior unit many years ago).
I attribute its lengevity to the fact it did not get that much use over the last 20 years.... because it is pretty expensive to run.
I only used it when it got really hot over summer. When I installed it in 2003 I had an asbestos roof and no ceiling insulation. Additionally, the lounge room I was cooling was exposed to both the morning and afternoon sun. The temp in my ceiling space was over 70C!! So I was trying to cool my interior AND my ceiling space. Not ideal by any stretch of the imagination.

Im 2009 I had ceiling insulation installed (pumped in cellulose fibre) courtesy of the government rebate at the time. Understandbably this made a huge difference to the overall efficiency of the Celestion 7.1kW

About 3-4 years ago my asbestos roof was replaced with a metal roof. Anticon insulation blankets were placed immediately underneath the roof sheeting. I also replaced the cellose fibre with "ceiling insulation batts" (I had to as the cellulose insulation had become contaminated with asbestion during the removal of the asbestos roof). Finally, I installed two whirlybirds to ensure that any warm air in my ceiling space is removed to reduce, if not eliminatre, any heat soak into the home interior.

On the exterior I have installed external sun shades on the eastern side to stop the sun from heating the side of the house. At the same time I had the celing insulation installed in 2009 I planted a wall of golden cane palms trees along the western side of my house which are now 5 metres high and serve as a very effective sunblock. All the shading has greatly reduced the heat soak from direct sunlight, but of course does not stop heat soak through the walls (which are not insulated) from the ambient temperature.

Despite the huge improvements to the insulation of my house, the 20 year old Celestion is still expensive to run. Because it is old technology (non inverter), when it is running, it is running at 100% capacity. So I am biting the bullet and replacing it (at considerable expense).

So hopefully the 6.3kW will be sufficient and efficient enough to nake a significient reduction in running costs. I am hoping that when in use it will spend most of the time using only minimal power as the inverter technology kicks in. Hopefully I can use it more often and have it cost less.

The 6.3kW is rated to operate from 2.3kW to 7.1kW (power consumption being from 0.2kW to 2.5kW). The 6.3kW system's minimum power comsumption of 0.2kW is half that of the 7.1kW system's minimmum of 0.4kW. Only time will tell what the actual runnins costs will be.
If I encounter a very hot day, the 6.3kW is actually rated to a MAX of 7.4kW

How long have you had your 7.1kW for? What are your running costs?

Incidentally, I have also purchased a MHI 2.5kW SRK25ZSA-W (installation is taking place tomorrow, $550). It is to replace an 20 year old Mistral 1.3kW split system in my bedroom that finally stopped working earlier this year at the end of summer (It has required repairs 2-3 times over the last 20 years).

I hope that that I get many trouble free years out of these two MHI systems.

Re regular servicing, Why do you think regular servicing is necessary? What exactly do you think needs to be serviced?
I never had a regular service performed on either of my two split systems since being installed 20 years ago. Nor did I perform any exterior cleaning of either of the two units. All I ever did was clean the interior filters. So to me regular servicing seems a myth. If properly installed, the system will never leak gas (my 20 year old Celestion unit is proof of that).

Thanks again for taking the time to reply to my enquiry.

Kind regards

Doug