Browse Forums Heating, Cooling & Insulation 1 Aug 23, 2020 9:29 pm Hi all Need some advice on heating/cooling. We are building a two storey, 45sq home, with 3m & 2.7m ceilings. The heating/cooling guy has advised that the house needs heating - 980 fan speed and cooling 26kw. He's proposing 2 systems as follows: System 1) Braemar TQ430-L XA which has 1050 fan speed + Lennox LCS-18 18kw single phase OR System 2) Toshiba RAV-SM22 22kw 3 phase system. Both systems will have 4 zones + a common area, with 12 vents. Problem I have is, friends have the same setup as System 1 for the single storey house, approx 30sq with 14 vents. So I am thinking the proposed systems and number of vents are not enough/underpowered to heat/cool the whole house. Also he states the house needs 26kw cooling and is proposing 18-22kw systems - are these sufficient. While he notes that we will only be able to turn on zones that do not exceed the system capacity, which I guess means we can in theory heat the whole house but not cool the whole house. Proposal has no vents provided in the kitchen, laundry, WIR/ensuite, separate bath and only 1 vent in rumpus area, which is approx the same size as the lounge which has 2 vents. So I'm wondering if the system needs more vents to heat/cool the house??? Also what are the running cost differences between single phase vs 3 phase system? Are 3 phase more expensive on power. Does anyone know if there is any kind of app/calculator where you can put in the house/room size and work out heating/cooling required, vent numbers etc. Sorry for all the questions, so many things to consider, we just want to get this right. Thanks in advance for any advice provided. ca Re: Heating/Cooling new home build 2Dec 23, 2020 9:30 am Hi Ca, It sounds like you have quite a large home and heating & cooling large can be a tricky exercise for residential homes. I would say if possible that you need to have a 3-phase unit otherwise it sounds like it's running right on the limit. If you have the option to upsize, do so. In terms of running costs, it comes down to the KW of the unit. Most new units are digital scroll, meaning the compressor ramps down once the house reaches temperature to reduce running costs. You may be able to find costs on the manufacturers website. In terms of having extra vents, it doesn't actually increase the heating/cooling capacity of the unit. Adding endless vents just for the sake of it is not always the answer. If there are areas that are not crucial for heating and cooling, consider removing entirely. Personally from a running cost standpoint, I would be leaning towards gas + add on cooling. Maybe have a second opinion to see what another company recommends. Im a big believer in having a larger unit than required. Hope some of this has helped. Can anyone recommend a good/affordable retaining wall and fence builder that I can get a quote from located in Sydney? 8 45838 If you are in Victoria you have a statutory right to your own building inspector regardless of builder's consent. No negotiations are required. However the builder will… 1 2943 Does anyone have a suggestion for a good hydronic in slab heating speacialist who may be able to help me with an existing system and wether or not it may need a seperator… 0 4889 |