QUOTE(7up @ Oct 10 2014, 11:17 AM)
Hi Sifu,
Can advise what type of aircond I should install for different areas below:
1. Living Room + Dining Room - Size about 50' x 20'ft
2. Family Room Upstairs - Size about 30' x 20'ft
3. Master bedroom - Size 30'x20'
4. Bedroom 1 - Size 18x15'
4. Bedroom 2 - Size 15x15'
Inverter/Non Inverter
HP
This is a rather large dwelling assuming it could be a super link, semi or bungalow.
Helpful questions:
1. Where are each room facing compass wise? Sun orientation influence on how much heat the building absorbs and re-releases into the night.
2. Is the house intermediate, end-lot or corner? Intermediate means got neighbour's house left and right to insulate from sun. Corner and endlot if west facing gonna have problem cooling without upsizing or shading technique.
3. How high is ceiling downstairs and what is the height after dropping plaster 3" below beam? If still 10' or higher can consider ceiling cassette. Otherwise don't.
4. What material is the roof using? Is it insulated with alu foil membrane sheet or rock wool battens (Coolbatts)? If got, then AC runs cooler upstairs. Otherwise may need to upsize.
Inverter saves in the long run at 50% running cost if you're ok with initial extra 50% cost over non-inverter. Assuming ceiling height to be 10ft upstairs and downstairs.
Assuming no insulation on roof top, heat load factor will be 70. Downstairs will be hlf=60.
1. Living room + dining room = 1000 * 60 = 60000BTU implies 3x2hp AC or 2x3hp AC
2. Family room upstairs = 600 * 70 = 42000 BTU = 2x2.5hp AC
3. Same as Family room
4. Bedroom 1 = 270 x 70 = 18900 BTU = 1x2.0hp or 1x2.5hp (2.0hp some models up to 18000BTU)
5. Bedroom 2 = 225 x 70 = 15750 BTU = 1x2.0hp (1.5hp insufficient as it's up to 13000BTU)
If roof has insulation, can bring hlf down to 60 and recalculate. Then downstairs can reduce hlf to 55. If corner, then all corner rooms on W and SW side needs to add 5 to hlf because of extensive baking by sun throughout the day.