Heatpump

tweake, Sep 13, 5:33pm
how big is the room ?
tweake, Sep 13, 8:33pm
the advantage of the cassette is its in the middle of the room and reduces the length it needs to throw the air. thats one thing mounted heat pumps are bad at as they throw and return to the same spot.

a mate has similar size room and normal high wall works ok but he has big ceiling fans which help a fair bit and its mounted up higher than normal so you don't get the same blast of wind as you do with 2.4 stud mounted ones.

the thing i don't like with cassette is they are mounted up in the ceiling and can be poorly insulated. pay to check the units insulation, if its not great make an insulated box for it.
i've only ever come across them in commercial buildings usually in false ceilings where the insulation factor is not an issue.
budgel, Sep 14, 11:32am
If you mean cubic metres, your room is 194.4 cubic metres: 9x9x2.4.
rdeans, Sep 14, 11:36am
We have just had a Cassette Installed. Its to service 2 rooms which it seems to handle fine. Family/dining/kitchen approx 51 sq mts and the other room is maybe 25 sq mts. We have it located close to the door to the second room rather then in the middle of the ceiling. It was dearer but less than 2 separate wall units. Hope this helps
rdeans, Sep 15, 10:23am
Sorry didnt see this yesterday, Its a Fujitsu 8kw heating 7.1 cooling.
johotech, Sep 15, 11:25am
Tauranga conditions are different than Christchurch.
johotech, Sep 15, 11:34am
In a brand new house, the 8kW might be ok for 81m2. You have to keep in mind that the unit's heating capacity is rated at an outdoor temperature of 7 deg, and reduces a lot under that, and especially below zero.

There are various calculators available, like this.
https://www.toshibaheatpumps.com/calculator/

You should be guided by the companies that have looked at the project and given you advice. A cassette unit in the centre might give you better airflow around the room. It depends if there is a good wall location for a wall mount to work when it's at a higher fan speed (which will be necessary with that size room).

Either option would probably work, because it's a new, double glazed and well insulated room.
gabbysnana, Sep 15, 7:48pm
i have a 16kw heatpump in the ceiling feeding 250sqmetres of home, cost $11k. Nice and warm.
tegretol, Sep 17, 11:24pm
We have gone the other way and put 3-4kW Hitachi pumps (<$1200 each) throughout the bigger rooms and a 5kW ($1800/2019) in the hallway to heat the bedrooms. Whilst it does mean more kit, the advantage is that we can turn on only those that are required. But the advantage is that if one karks itself then fixing/replacing it will be pretty trivial (and less inconvenient) compared with a big unit. Given that these units are now nearly 4:1, their heat is bloody cheap.
tweake, Sep 18, 6:21pm
i'm getting another heat pump put in in the other bedroom.
tend to run bedrooms a bit different to the main rooms so it pays to have separate systems.

the trouble with ducted heatpump is the house really needs to be built for it.

looked at multi split system (ie one outdoor unit) but efficiency tends to take a dive and performance varies a lot depending on what indoor units are running. they are probably better for large rooms with a few indoor units that all run at the same time.
gpg58, Sep 18, 7:39pm
Aside from the fact that if the outdoor dies, just like many ducted systems, you have lost all heating for the house.
Also i seem to recall some media coverage, of someone needing entire 4 room multisplit system replaced when it happened(think at 6-8 years old), as no compatible replacements were available.

Re cassette units, if i remember correctly, there was once upon a time, a model that had provision for a duct to be taken off it, to another area, think it was instead of one of the 4 side discharges.
joanie32, Sep 19, 8:15am
I shake my head when people proudly tell me they have just spent a gazillion
Dollars on multiple heat pumps and ventilation systems.
We have windows that open, a fireplace and most importantly MINIMAL HEAT LOSS.
People have been sucked in to think it’s hard and complicated to keep a house warm and dry, when in reality it’s very easy, and very cheap if you give it a bit of thought.
tweake, Sep 19, 10:26am
unfortunately most nz houses are not built for minimal heat loss as there is no legal requirement to do so.

the other factor that comes into play is most kiwis are taught to have cold houses.
kiwis simply do not heat homes very well but still claim thats its "warm and dry".
once you put temp gauges in there it shows they are putting up with cold houses.
tweake, Sep 28, 12:13pm
but i don't want windows open due to security, noise, dirty air (especially pollen), and excessive ventilation.
don't have a fireplace as i don't have access to cheap/free firewood anymore.
multiple heat pumps because they only heat per room.
don't have to clean chimneys, less fire risk (insurance). don't need a wood storage/drying shed and heatpump takes up less space in my small house.
and i havn't spent a gazillion dollars on a decent sized fireplace thats capable of heating the whole house.

different methods for different reasons.

the big thing tho is ventilation systems. being able to get good ventilation with clean filtered air without loosing as much heat as windows do and while the house is fully closed up as your away at work etc.