Air con unit for small guesthouse

[sumyunggai]

I am building four rooms, each around 25 square metres, and arranged in an L shape (so roughly 15 metres long on one end, and 10 metres on the other). I am not sure if they will be too hot, so I will try first without a/c, because the costs here are too high:

1. appropriately sized genset ($$$$)

2. naikkan daya PLN ($$$)

Anyway, what is a good cooling solution for four separate guest rooms, in the case that I do install a/c? And what kind of infrastructure do I need to add at the building stage for a later retrofit?

 

[Bad_azz]

I am building four rooms, each around 25 square metres, and arranged in an L shape (so roughly 15 metres long on one end, and 10 metres on the other). I am not sure if they will be too hot, so I will try first without a/c, because the costs here are too high:

1. appropriately sized genset ($$$$)

2. naikkan daya PLN ($$$)

Anyway, what is a good cooling solution for four separate guest rooms, in the case that I do install a/c? And what kind of infrastructure do I need to add at the building stage for a later retrofit?

Personally I hate AC in bedrooms (am thinking hotels & guest houses I have visited) 'cos 99% of the time it blasts straight at the bed.
If A/C is something you are hoping to avoid , why not try with ceiling fans first- better for the environment and cheaper overall.

 

[sumyunggai]

I like ceiling fans and I'm currently in a 26C room with a ceiling fan and it's cool and I will fit fans for sure. BUT, I want to be prepared for the eventuality that the room is hot. (My current room has lots of ventilation, the new one will not because it's near a road and I don't like noise)

 

[Smallworld]

Personally I hate AC in bedrooms (am thinking hotels & guest houses I have visited) 'cos 99% of the time it blasts straight at the bed.
If A/C is something you are hoping to avoid , why not try with ceiling fans first- better for the environment and cheaper overall.

BA - was it even when you used air swing? Those air swings can blow AC air at almost 90 degrees so ---- vertically.

But I do agree I would go with fans and proper air flow (draft) as min. setup easy to make/buy and cheaper. If that would not pass the test then I would go for more expensive solutions - AC.

 

[jstar]

Yeah, you should never install an aircon aimed at your bed. Unless you want a stiff neck.

Anyway, four rooms with all individual solutions are gonna cost you. Let's say you will need between 0,5 and 1 PK for a 5x5 meter room. It is easy to calculate the BTU, just google that. There are solutions with multiple indoor units connected to only one outside unit (so you can add) but I found out the cost is even somewhat more. So it is esthetically more pleasing but not cheaper.

The best brand is Daikin, the worst probably the Chinese brands nobody ever heard of in Glodok Electronic etc. Everything in between as Sharp, LG, Samsung, Panasonic, is pretty good. Some brands like Sharp and LG have a lower power setting, then you could go to 250-600 Watt.

Preparation: You can not really foresee the tubes between inside and outside units since they are very expensive. (And up to 2,5 meters normally included.) Just make sure there are wall openings, ducts and indoor power outlets on 2.5 meter high. And keep the inside and outside units rather close since extending and adding longer tubes will be expensive.

Another option would be to use a mobile or portable unit with an exhaust hose.

 

[Bad_azz]

Some of the better hotels with bigger rooms have been better- but to be honest I am just not a fan of AC at all- it makes my skin dry out and me just feel malaise.

 

[CaturMuka]

Anyway, what is a good cooling solution for four separate guest rooms, in the case that I do install a/c? And what kind of infrastructure do I need to add at the building stage for a later retrofit?

4 individual split AC systems would be the way to go. I've got six 330W Samsungs, which I'm surprisingly happy with. I though there was no way they'd be strong enough, but I had 2 adults and 2 kids staying in one 8m x 3m bedroom and it was more than cold enough.

And what kind of infrastructure do I need to add at the building stage for a later retrofit?

This depends upon the position where you want to install the unit and how neat you want the final installation to be. If the fan/compressor box is going to installed on the outside wall directly behind the AC unit then there's nothing you need to do, except have a power point installed next to where the unit will eventually be. I think you're supposed to use the British style power point for this because apparently it matters that the live and neutral wires match up with those of the unit. Also, I think there's an extra fuse inside the power point. That's what my AC guy said anyway.

If you want the unit to be placed somewhere else, like say, above a door (the best position for a bedroom IMHO) then it all gets a lot trickier. You'll need a 3/4 inch PVC pipe to be installed to drain away the condensate. Make sure the pipe starts off vertically, it's no good having a pipe that starts out horizontally. I trusted the plumber to do it and had to rip out and re-do two of them. This is a bit weird, but it's better if the pipe isn't 100% vertical. A drip that falls from 2-2.5 metres can make a lot of noise, and it sounds more like a tick from the mechanics of the unit than a drip of water, drove me crazy until I figured out what it was.

You'll also need to pre-install the copper pipes and electrical cable that run from the unit to the fan/compressor box. These absolutely must be insulated, otherwise they'll gather condensation and drip into your ceiling or wherever. Not sure there are AC guys who wouldn't know this, but you never know.

The copper piping and cable will need to be long enough to reach the intended installation point of the fan/compressor box. Check the length yourself as they stuffed this up with me on two units as well.

Not sure all AC guys know this, but there actually is a minimum distance for the length of the copper tubing. Usually around 2.5 - 3 m, if I'm not wrong. The maximum distance can be surprisingly long too, sometimes around 10m from the unit. Check the manual that comes with AC unit, I can almost guarantee you that your AC guy won't.

I find the noise from the fan/compressor box really annoying so it's better that the box doesn't actually touch the wall and make sure to use the rubber footings on the metal brackets to stop the vibrations travelling through the solid wall. If it's not too late, use 'Bata Ringan' (i.e. light weight, aerated Concrete Blocks) in your walls for better noise and heat insulation.

Two other things I've found annoying:
- My fan/compressor boxes turned out to be made of plastic. If it's in direct sunlight, this will only last a year or so before it becomes brittle and falls apart. Make sure the box is made of metal.
- The temperature sensor should ideally be in the remote itself, not in the AC unit. It's weird having to set the temperature to 29 even though you want it at 25 because the AC unit will always be installed high up and therefore hotter than at couch or desk level.

Here's a photo of one of my units, installed above a doorway, before it was neatened up.



Lastly, I didn't actually want to know anything about air-conditioners. Screw you Indonesia!

 

[sumyunggai]

good info. Yeah I was looking at the LG or Panasonic inverters either the 320W or 680W. We are using beton ringan (2*10cm blocks with a 10cm cavity). We also are putting in a flat concrete roof, which I think is not thick enough to keep out the heat (from what I can see, concrete beams of say, 40cm, don't heat up during the day, but a 15cm concrete floor/roof gets hot). We have 3.5 metre high ceilings.

I am not planning on any kind of natural ventilation (common here is 'lobang angin' - i.e. holes with (often torn) mosquito mesh over them), because it just seems to let in a lot of noise.

 

[Bad_azz]

good info. Yeah I was looking at the LG or Panasonic inverters either the 320W or 680W. We are using beton ringan (2*10cm blocks with a 10cm cavity). We also are putting in a flat concrete roof, which I think is not thick enough to keep out the heat (from what I can see, concrete beams of say, 40cm, don't heat up during the day, but a 15cm concrete floor/roof gets hot). We have 3.5 metre high ceilings.

I am not planning on any kind of natural ventilation (common here is 'lobang angin' - i.e. holes with (often torn) mosquito mesh over them), because it just seems to let in a lot of noise.

I think part of their reason to be is to let the air circulate to stop the walls rotting

 

[jstar]

^
Yes, but -especially over here- the dehumidification of an AC is as important as the cooling function.

And humid air in = humid air out. So natural ventilation can only achieve that in 'wet rooms'. (Dispose the additional humid air.)

 

[CaturMuka]

I think part of their reason to be is to let the air circulate to stop the walls rotting

That's fair enough, but it'd be a lot better if they built their houses to avoid moisture getting in the walls to begin with.

There's an almost universal blind spot in Indonesia that rising damp doesn't exist and therefore they do nothing to prevent it. As far as I know, you still can't buy black builders plastic to put between the floor and the earth. I used karpet talang and that's been successful.

Also, simply extending the eaves all the way around the house would do a lot. Keeps rain (and if you're lucky, sunlight) from directly hitting the walls.

 

[CaturMuka]

. . . but a 15cm concrete floor/roof gets hot).

Any chance you can paint or tile it white? We've got a whole side of the house that gets full sun from about 12.30pm until sunset. Painted it with white waterproofing paint and was happy with the reduction in temp. Beforehand, the interior wall could get quite warm to the touch but after the paint job I really couldn't tell anymore from the inside. A small part of the wall was done in just 'White' paint and the rest was finished off with 'Super White', I couldn't give you an exact number but there was a significant difference in temp between the 2 'Whites'. 'Super White' was brighter and therefore better at reflecting away the sunlight.

The builders honestly thought I was stupid to use white, and I thought they were stupid for wanting to use dark grey.

 

[Davita]

RE; post #12
I agree. We bought our villa in Bali when it was 99% constructed and the sun-facing wall already had that ridiculous battleship-grey waterproof paint. I asked for it to be changed to white and was told..."banyak mahal!" Other things were a priority but I always planned to paint it a quality waterproof white.
Next thing I know is the plot of padi-land next to the wall was being developed into another villa complex. A similar villa to mine was built only a metre from my wall so I said they had better close the top as there would be no room to paint in the future.
The two bedrooms that shared that wall are now very cool as the boring-looking grey wall is now shaded by another villa and the rain doesn't penetrate.

 

[jstar]

Talking about water, humidity etc.: Of course CaturMuka is correct that over here, most of the time they will not apply the membrane layer just above the ground level.

But the whole philosophy in building walls is different from what we were/are used to. In a new built, you see a karkas with pillars and floors in concrete. Between the pillars the walls are most often a single brick layer, that is the small solid brick, not the big model. If you're lucky they will use the white ACC blocks. Then the outside will be sealed. With cement (and additives if you're lucky), the grey sealant and paint (for the street visible walls).

What they don't know at all, is the cavity concept. So with two walls and an empty (or insulated) space in between.

Now, you might argue that a solid matter always insulates better than a open space. And that the cavity will attract insects and what not.

True, but then the walls need to be much thicker than what they apply here. And a major issue is the sealing; the cavity concept contains drainage and it has outside openings from which the humidity evaporates. The humidity in the walls here, practically has no chance to get out, besides to the inside. Inflow and exhaust water pipes only add to that problem (condensation etc.) since they are not in a cavity space but in the brick wall and plaster (gypsum stucco).

With a sadle roof you can at least overlap the walls with the roof (and the hot air will go up as an added advantage). But with a flat roof, that is asking for problems.

 

[CaturMuka]

What they don't know at all, is the cavity concept. So with two walls and an empty (or insulated) space in between.

Not sure if you're actually advocating that they use the cavity concept here, but if so, I can't really agree. I think these are really suited to places which get harsh winters. I imagine you'd get your money back in reduced heating bills. Not sure about other areas of Indonesia, but here in Bali we typically only use the AC for guests and at times of unusually high humidity. We'd never recoup the extra cost.

It's a huge cost and complication to a project when your real aim should be to just keep moisture from getting into the walls in the first place. You can achieve this much easier by using simpler, cheaper methods. They just refuse to even think about it here.

The loss of internal floor space would've ruled it out in our house and I think most Indonesians would feel the same.

And that the cavity will attract insects and what not.

Absolutely, I'd pretty much dismiss the idea for this reason alone. Cats, rats, geckos, ants, termites, bees, wasps. It'd be like having your own zoo. Sorry for the hyperbole but I've had significant problems with all of these.

With a sadle roof you can at least overlap the walls with the roof (and the hot air will go up as an added advantage). But with a flat roof, that is asking for problems.

That's true, but there's a lot you can do with a flat roof. I've got 4 of the AC fan/compressor boxes (absolutely can't be heard from inside, and they don't annoy the neighbours) up there and a couple of small storage sheds. You've really got to check that the drainage is done properly though. They used cementitious waterproofing on my flat roof which, in my opinion, is just a waste because it's not a flexible material so as soon as it develops cracks it's useless. My next project is to rip this up and tile it with those cheap, white, 30cmx30cm tiles. I'll then use water proofing paint to seal the grouting between the tiles. I already used this method to seal the roof of a 4m x 1m skylight, and there's been no leaks in the 1 and half years since it was done.

Even though it'd be risky, I sort of feel that you could get away with no waterproofing at all on a thick concrete roof, as long as your drainage was top notch.

 

[Davita]

My good friends in Vancouver own this Company which has an international reputation solving wet cement issues....http://www.kryton.com/about/our-story/.
They have a distributer in Jakarta.

 

[jstar]

Not sure if you're actually advocating that they use the cavity concept here,

Nope, my point was:

.... the whole philosophy in building walls is different from what we were/are used to.........

..... the walls need to be much thicker than what they apply here.

Of course it's easy (and perhaps desirable) to accept the 'quick and dirty' as-long-as-it-looks-good approach we see here. Esp. if you want to flip, resell within 5 years or you don't mind a complete overhaul in 10 years. Now if you plan to live somewhere for the long term and don't want to deal with this maintenance crap all the time, it's a different story. There is no enforced 10 year warranty on buildings and renovations here.

If you don't have the knowledge or time yourself, I would get a supervisor with building contracting experience in Oz, the US or Europe. (Perhaps even someone residing here already on KITAS/P.) Of course you can not apply all good construction practices, but at least you have someone with a better background overseeing and correcting the work for you.