Recommendations for Air Conditioning expert in Auck ?

Forums › Home Workshop DIY › Recommendations for Air Conditioning expert in Auck ?

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8

6325 posts

Uber Geek

#3018606 8-Jan-2023 15:50

timmmay: I suggest running any design past us in this thread, there's quite a bit of experience in here, and I think tweake is a professional.

Yep I agree, is the beauty of a community who are mostly constructive.

The problem with the one we were going to use is they didnt show us any design before wanting to install. Original plan was a little complicated and would impact house aesthetics. So now we are likely to go through the roof instead and place the inverter where we will not hear it and it have it placed where it makes minimal impact to the house aesthetics ie back not front.

Im seeing some really cheap units out there that seem to get good reviews, ie not the usual suspects (fujitsu, mitsubishi, panasonic etc) that are half the price of the Fujitsu. I "think" an install that is fairly standard isnt overly expensive. Possibly saving $750-1k on a small unit. Not afraid to give the unknown brands a try if they check out legit on the net.

tweake

2391 posts

Uber Geek

#3018609 8-Jan-2023 16:08

timmmay: I suggest running any design past us in this thread, there's quite a bit of experience in here, and I think tweake is a professional.

not a pro, just a mere amateur. its just an interest of mine as i tend to do things myself.

NZ is just behind the ball game and there is a lot of "professionals" out there who are nothing more than salespeople who don't give a crap once you have paid.

NZ's whole housing scene is a nitemare and the only way its going to get better is to educate the customers better.

TeaLeaf

6325 posts

Uber Geek

#3018626 8-Jan-2023 17:44

tweake:

there is a lot of "professionals" out there who are nothing more than salespeople who don't give a crap once you have paid.

That was pretty much our experience first time around. Salesman with enough information to be dangerous, but nobody technical giving us details on the installation.

Im hoping the chap mentioned earlier who is an air conditioner installer himself and well as company owner, will do a better job with plans etc.

Is it wrong to expect an actual formal design?

timmmay

20574 posts

Uber Geek

Trusted

Lifetime subscriber

#3018638 8-Jan-2023 19:08

I paid $14K for a ducted system and didn't get a design, just a parts list. I suspect most choose the size of the outdoor unit based on experience rather than facts, take a guess at the best duct sizes based on experience.

When I had our bathroom redone 10 years ago I didn't get a design either, even though we paid the better part of $40K and used a good bathroom firm in Wellington. I had to learn 3D modelling with Sweet Home 3D to mock something up because I was having trouble visualising what they were saying. The firm was quite impressed at what I'd done with the modelling software. My father in law used to do bathrooms in the UK 20 years ago, he used dedicated design software.

tweake

2391 posts

Uber Geek

#3018642 8-Jan-2023 19:11

TeaLeaf:

Is it wrong to expect an actual formal design?

i've not heard of anyone doing one on regular houses. probably find someone might do it on a high end house or performance build.

most are just an experienced guess. there is some basic hvac calcs web sites around. i have used one of the govt ones before which was ok for me.

the other factor is our houses really are not designed around having HVAC. many new homes have no space to fit heating or ventilation gear, let alone fit that gear inside the envelop. so its always a bit of a hack job.

tweake

2391 posts

Uber Geek

#3018643 8-Jan-2023 19:14

timmmay:

I paid $14K for a ducted system and didn't get a design, just a parts list. I suspect most choose the size of the outdoor unit based on experience rather than facts, take a guess at the best duct sizes based on experience.

When I had our bathroom redone 10 years ago I didn't get a design either, even though we paid the better part of $40K and used a good bathroom firm in Wellington. I had to learn 3D modelling with Sweet Home 3D to mock something up because I was having trouble visualising what they were saying. The firm was quite impressed at what I'd done with the modelling software. My father in law used to do bathrooms in the UK 20 years ago, he used dedicated design software.

so many NZ companies are run on a shoe string with no reinvestment, and using the cheapest tools they can for the job even if it makes them inefficient.

timmmay

20574 posts

Uber Geek

Trusted

Lifetime subscriber

#3018648 8-Jan-2023 19:28

I watched a few HVAC videos on youtube from the USA. They design the systems into the houses, because of that the systems do a better job.

Equinox IT

Cloud spending continues to surge globally, but most organisations haven’t made the changes necessary to maximise the value and cost-efficiency benefits of their cloud investments. Download the whitepaper From Overspend to Advantage now.

Handle9

11386 posts

Uber Geek

Trusted

Lifetime subscriber

#3018674 8-Jan-2023 21:06

timmmay:

I watched a few HVAC videos on youtube from the USA. They design the systems into the houses, because of that the systems do a better job.

Not really, they mostly do it rule of thumb but they have been doing it for a much longer time.

Domestic HVAC design is crap in most places in the world.

TeaLeaf

6325 posts

Uber Geek

#3018779 8-Jan-2023 22:08

Handle9:

Domestic HVAC design is crap in most places in the world.

Good to know.

Most the propertys I own or lived in, in SE Australia do not have HVAC, AC is not a given either but more mainstream.

NZ builds a lot of wood homes, more so they lack the ventilation or the dehumidifying mode of an AC.

Im blimmin surprised turning my 6kw main AC on with Dry Mode, if I leave it run an hour, it will seep into the hallway and the bedrooms. Hardly practical or efficient thougn.

insane

3236 posts

Uber Geek

ID Verified

Trusted

#3018800 9-Jan-2023 00:22

tweake:
...

i would say both.

however when i say bad, the worse i've heard of actually been measured was 2:1. ie loose about half the units efficiency. it will vary a lot depending on the setup and how its used.

wear and tear will go up. the hardest thing for a compressor is start up. some compressor setups have maximum number of starts per hour. to many starts it flags an error.

also, depending on the units, some will have poor temp control. to reduce the amount of starts/stops they will let indoor temps change a lot more before starting (to give it more load to make it run longer). sometimes that can create comfort issues.

I tend to agree with most of what you're said, but in reality havn't noticed the difference when it comes to cost to run.

Almost every compressor is now an inverter unit so it's not the old on 100% or off setup of the 90's. They throttle and cycle based on demand so it's offset a bunch.

I replaced one of my 3.5kw split units for a 4x multi-split 7.1kw and frequently run only one or two heads. I have a seperate 5.4kw unit for my living area.

Yes the minimum power draw is not as low as a single unit, its 1700w vs 1100w according to the spec sheet, but the larger compressor I guess is cycling more so it's not noticed in practice. I would concede that at times the Panasonic's actual vs set temperature can vary a degree or two, which is only annoying in the kids room at night.

I have now got every bedroom and living area in my house and granny flat airconditioned and am still amazed at how efficient heatpumps are. If only I had a ultra energy efficient home to not require them at all!

TeaLeaf:

Is it wrong to expect an actual formal design?

I've used EES for the 4 of the systems I've had installed and always received a basic 2D design. Shows the floorplan of the house, the volume per room, placement of the indoor and outdoor units as well as the copper piping runs and power runs, switchboard etc.

I'll spost one if I can obscure my details from it...

timmmay

20574 posts

Uber Geek

Trusted

Lifetime subscriber

#3018845 9-Jan-2023 07:49

insane:

Yes the minimum power draw is not as low as a single unit, its 1700w vs 1100w according to the spec sheet, but the larger compressor I guess is cycling more so it's not noticed in practice. I would concede that at times the Panasonic's actual vs set temperature can vary a degree or two, which is only annoying in the kids room at night.

I have now got every bedroom and living area in my house and granny flat airconditioned and am still amazed at how efficient heatpumps are. If only I had a ultra energy efficient home to not require them at all!

We have the whole house air conditioned too. Ducted for the living area with individual room temperature control, high wall for the kitchen (it needs to be separate), and a small one for my office. It's really nice to have.

The ducted unit has a minimum output of 4kw, which is pretty high, so it cycles. With the Airtouch if you set to 22 degrees it heats to 22.5 then turns back on when it's 21.5.

I had a Panasonic ducted unit removed. Horrible thing, loud and poor control. Daikin with Airtouch is much much better. I wouldn't recommend Panasonic to anyone.

billgates

4705 posts

Uber Geek

Trusted

#3018863 9-Jan-2023 08:44

We have the Mitsubishi ducted unit with the specs below which as you can see, power input is quite high minimum for both cooling and heating. I can now tell with the energy monitoring system for house loads what power the ducted aircon is using at any given time but it's nowhere near as the minimum input of 4.37kW for cooling. If the temperature needs cooling is within 2 degrees, then it's usually using about 2kW to 3kW and if its 1 degree then it's using around 1kW to 1.5kW.

Do whatever you want to do man.

timmmay

20574 posts

Uber Geek

Trusted

Lifetime subscriber

#3018886 9-Jan-2023 10:11

billgates:

We have the Mitsubishi ducted unit with the specs below which as you can see, power input is quite high minimum for both cooling and heating. I can now tell with the energy monitoring system for house loads what power the ducted aircon is using at any given time but it's nowhere near as the minimum input of 4.37kW for cooling. If the temperature needs cooling is within 2 degrees, then it's usually using about 2kW to 3kW and if its 1 degree then it's using around 1kW to 1.5kW.

That looks about right. The "Power Input" looks like maximum current draw. If the minimum output for cooling is 6.2kw, and say the COP (efficiency) is 3.0, that means for the minimum 5.7kw output it requires (5.7 / 3.0) = 1.9kw. If the efficiency is better than 3.0 (looks to be better) then the power requirement is lower. That suggests that if it's producing 18kw of heating with a COP of 3.6 the power draw would be 5.1kw.

tweake

2391 posts

Uber Geek

#3019152 9-Jan-2023 17:03

insane:
tweake:
...

i would say both.

however when i say bad, the worse i've heard of actually been measured was 2:1. ie loose about half the units efficiency. it will vary a lot depending on the setup and how its used.

wear and tear will go up. the hardest thing for a compressor is start up. some compressor setups have maximum number of starts per hour. to many starts it flags an error.

also, depending on the units, some will have poor temp control. to reduce the amount of starts/stops they will let indoor temps change a lot more before starting (to give it more load to make it run longer). sometimes that can create comfort issues.

I tend to agree with most of what you're said, but in reality havn't noticed the difference when it comes to cost to run.

Almost every compressor is now an inverter unit so it's not the old on 100% or off setup of the 90's. They throttle and cycle based on demand so it's offset a bunch.

absolutely bang on.

variables help a lot, but they still have limits. it also depends on actual cost of running. if mine lost half their efficiency would i even notice the extra $10 running cost, probably not. if your bill went from $100 to $200 you might notice. so its very application dependant.

tweake

2391 posts

Uber Geek

#3019709 10-Jan-2023 18:05

Manual J or Not? How to Tell If Your HVAC Design is Bogus

even overseas getting proper design can be problematic. recent vid just to highlight some of the issues.

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8