Bedroom air con size

[OnMyWay]

I'm too lazy to research this and I figured some of you guys know.  What is the correct size non-inverter window-type aircon for a 13 X 10 bedroom?  Infrequently used.  Less than 1 hp?

[Dave Hounddriver]

Depends on the room.  I have a 20 sqm bedroom and a 1 HP does not cool it during the day because there is a tin roof and no insulation.  I had the same size room in a shady spot with an insulated ceiling and cooled it with a 3/4 HP.  You mileage will vary depending how hot that room gets.

[OnMyWay]

14 minutes ago, Dave Hounddriver said:

Depends on the room.  I have a 20 sqm bedroom and a 1 HP does not cool it during the day because there is a tin roof and no insulation.  I had the same size room in a shady spot with an insulated ceiling and cooled it with a 3/4 HP.  You mileage will vary depending how hot that room gets.

It is about 12.5 sq meter with an attic above it.  2 large windows, one in shade and one gets morning sun.  It is rare that we use it in the daytime.  It is my 3 year olds / guest room and we use it just a bit.  When when we have guests we use it more.

Current one is an old Samsung that is getting really noisy and all the vent direction control thingies are broken.  Time to retire it, I think.  I don't know what the HP is but maybe 1.

[Dave Hounddriver]

If it was me, from what you have said, I would get a 3/4 or a 1 HP.  There is not a huge difference between the cost or perceived cooling power of either of those (window units).

I cooled a 2 m x 3 m room with a 1/2 HP but that would not be enough for your room so 3/4 or 1 HP depending how cool you want it and how much daytime use it might get.  Of course a 1 HP split inverter would be sweet but that would set you back 25 to 30K pesos, installed.

[hk blues]

Always best to go over than under size, yes it costs slightly more to buy and to run but a waste of money installing a unit that doesn't do the job.

[OnMyWay]

40 minutes ago, hk blues said:

Always best to go over than under size, yes it costs slightly more to buy and to run but a waste of money installing a unit that doesn't do the job.

Recalling my research when I bought my big splits, that is true in some cases.

According to what I read, if you buy inverter type, it is best to go slightly over the technically calculated need for the room.  The inverter motor will cool the room, then wind down, saving electricity.

If you buy non-inverter, it is best to go SLIGHTLY UNDER the technically calculated need for the room.  Then the compressor will run constantly without turning off.  Turning on and off is what uses the most electricity.

Agree that going under too much would be a failure!  So there is a fine line there.  If your non-inverter has too much power, it will turn on and off a lot, thus using more electricity.  I have that in one of my rooms now.  The previous guy replaced a big window unit with a split, and moved the big window unit to a small BR.  It is way too big but that is not the one I am replacing now, because my other daughter doesn't like air con much.

[Jack Peterson]

We have said it before but can I presume we are all having these units cleaned on a regular basis, this is my biggest problem. Dust that cogeles with condensation and reduces the effectiveness of some parts.

 Just saying

[Jollygoodfellow]

58 minutes ago, hk blues said:

Always best to go over than under size

That's what my girlfriend said to me.  Off topic I know 

[BrettGC]

Link to a consumer reports size guide for window air con:

https://www.consumerreports.org/window-air-conditioners/how-to-size-a-window-air-conditioner/

Link to BTU/hr to kW:

https://www.rapidtables.com/convert/power/BTU_to_kW.html

Link to HP to kW:

https://www.rapidtables.com/convert/power/hp-to-kw.html

 

[allancomeau]

Whatever you decide best to get the room insulated as best you can.

After all its not cost of them that is the problem, it is the Mercalco robbery that occurs monthly