Buying Home Air Conditioning

Basically, What you can buy is a split system for each room that you want to cool. Whether they say LG, National, Carrier or what ever, their doesn't seem to be much differance in the brands.

Be sure that the outside unit is not enclosed. The more open to the air the better. A big deal is determining the cooling capacity needed to cool each room or zone. I took a couple of semesters of Title 27-J at UCLA while I was Service Manager for an AC Contractor learning how to calculate load. But, that was over 30 years ago.

I'd suggest going to a big store, like Big-C and using their recommended installer unless you know some knowledgable construction people. The store will try to sell you a bigger unit than is optimal as it is more expensive and profitable. Including installation and the tubing count on somewhere around $300.00 USD or $6-7,000,000 VND per room.

Vacuum pumps seem unknown here. So, they use a few tricks, to mostly get the moisture out of the system. Not ideal. I don't like it. But it works reasonably well.

70 years old wrote:

The store will try to sell you a bigger unit than is optimal as it is more expensive and profitable.

That may be the store's motivation, but my understanding from a repairman in the US who had no interest in sales, was that it was better to get as oversized a unit as you can reasonably afford.  His reasoning is that it will cycle less frequently, thus saving electricity, and also will need fewer repairs.  An undersized unit runs all the time.

THIGV wrote:

70 years old wrote:

The store will try to sell you a bigger unit than is optimal as it is more expensive and profitable.

That may be the store's motivation, but my understanding from a repairman in the US who had no interest in sales, was that it was better to get as oversized a unit as you can reasonably afford.  His reasoning is that it will cycle less frequently, thus saving electricity, and also will need fewer repairs.  An undersized unit runs all the time.

We don't exactly disagree. A proper load calculation does optimally size the unit for the best cycling time. I also doubt your friend is suggesting a 100,000 BTU A/C for a 200 square foot room. Too big a unit also has disadvantages. These include dehumidification, required electrical upgrades, physical size, more frequent temperature swings and more.

Note, like most Service Managers, I was a repairman before I got promoted. Also note, A/C repairman and A/C installer are separate operations in all but the smallest A/C companies. Now I was never an Installation Manager. But, I did pass the California Heating and A/C Contractor's License Test and that is mostly dealing with Installation planning issues.

Again, It has been 30 years since I worked in that field.

Short Cycling (from an over sized AC unit) causes mold, because while it does cool faster, it does not have sufficient time to remove the moisture.

A Licensed Home Inspector in my old life.

Zep--

I have to concede that the advice I had was from a man who's business was in the very dry leeward side in Hawaii, so the moisture factor may not have been important in his reckoning.  In the moister climes in Hawaii very few people bother with A/C as the comfort level is nearly ideal.

Thanks guys, I did a few of the various online calculators for btu and hp etc etc which takes in dimensions plus sun facing room etc and it seems I need somewhere between 1.5 and 2hp.  Will be going for 2hp units and that gives some headroom.  Also have a perfect spot for the compressor, it is somehow still under cover but will full flow  of air.   

I asked a couple of times in BigC but I seemed to more than the sales guys and I don't know very much   My wife also asked but it seems they hadn't had any product training and just pointed at prices.   

If anyone has any recommendations then that would be great also!!

Why dont you try sharp . I am distributor of sharp a/c  there are made in Thailand, intergrated ion maker inside. May i know where do you want to install it? How many set? Room size (15, 18, 21 sqm)?? Jack

Hi Speedbonnieboat,

There are several reputable suppliers in Vietnam who sale electronic devices are Nguyenkim (Nguyễn Kim) or Dienmay (thế giới di động). Just visit their showroom and get advise from their staffs.

Website: nguyenkim.com/?gclid=CMbfpe780dACFZclvQodq7ADKA
dienmayxanh.com/

I prefer Daikin than others branches.

Hi SpeedBonnie Boat,

I have purchased and had a total of eight Invertor type Daikin AC units and am totally satisfied with them.

I work for a very large Mechanical, Electrical, Air Conditioning etc. construction company in SE Asia region and my company deals with very many different Air Conditioning companies from individual room units to major construction systems for hotels etc.

All in all for personal use the invertor type AC units are economically the best for running costs. A slightly larger unit is preferable where the smaller unit is marginally the right size for the room (note slighly larger - NOT overkill!). Daikin was the popular brand at the time of purchase but all of the International brand names are acceptable, bearing in mind that invertor type is preferred. I bought from one of the largest  retail outfits and had their installer install the units. For service and repairs I use a small local company to service (no repair as at the moment).

Hope that this helps.

saigonhome1 wrote:

Why dont you try sharp . I am distributor of sharp a/c  there are made in Thailand, intergrated ion maker inside. May i know where do you want to install it? How many set? Room size (15, 18, 21 sqm)?? Jack

As most residential construction in Viet Nam these days is brick, using room size to calculate A/C capacity works pretty well most of the time.

But, a lot of things can change the A/C requirements. Window size, location, single glazed or insulated and do they open or not?, number of doors, any doors opening to the outside, number of outside walls and number of people who will be in the room normally and maximum should be considered as well. Also will a bathroom door be opening into the room? How close to the kitchen? All of these things do add to the A/C load.

Thanks again everyone, I have Daikin units in Singapore as it is really popular here, Panasonic too also popular and I used Panasonic in Jamaica without issues  so it seems that I just need to go around and talk to the various places......Thanks again!!