Temperature Control - Is it windows and doors closed, blinds down and fans on, or windows and doors wide open?

[Pilotman]

I have never really solved this issue to my satisfaction.  I have a house in an area that gets very little natural breeze, some, but not much.  During the hot days, do I lock the house down, windows, doors and blinds and live like a mole, using just fans, as I don't use aircon in the day, or is it better to open all windows and doors and catch what small air flow there is, often none at all?  Having tried both methods I can't decide which is the most efficient in keeping the house coolish.  Mrs P prefers the open house method, but I'm not sure that is the best way.   What are the experiences/opinions/advice of Members? 

[jackdd]

Depends on the insulation of your house, especially the roof.

Considering that the insulation here in Thailand usually sucks, I'd say open doors/windows is cooler.

[CharlieH]

Depends how much you enjoy all the bugs etc and geckos and god knows what entering the "open house" 

 

I keep it closed everywhere, occasionally open the windows with fans but the windows all have mesh screens to keep out the bugs. Etc

[Crossy]

Everything wide open with fans and loads of shade plants.

 

Until it gets dark and the Creatures of the Night are abroad at which point we retreat into the A/C.

 

[Moonlover]

21 minutes ago, jackdd said:

Depends on the insulation of your house, especially the roof.

Considering that the insulation here in Thailand usually sucks, I'd say open doors/windows is cooler.

We're the same. We have an old, but refurbished village house with A/C in the bedroom only. Madam Moon is always up before me (she likes to feed the monks) and as soon as she's up she opens every door and window in the house. And it stays that way all day except when we go out.

[FritsSikkink]

Start using the AC

[Pilotman]

7 minutes ago, FritsSikkink said:

Start using the AC

I didn't come here to live in a fridge all day. Just want a cool house, a few degrees below the outside temperature, not a cold one and why spend the money when you don't need to? 

[jak2002003]

8 minutes ago, Pilotman said:

I didn't come here to live in a fridge all day. Just want a cool house, a few degrees below the outside temperature, not a cold one and why spend the money when you don't need to? 

Agree with you.

 

Also relaying of air con so much means people can't acclimatise to the weather here and will always feel too hot when they don't have it on.

 

We only use it in the evenings here in CM during the very hot dry season. We also keep the house windows and doors closed then, but that is more to do with the air pollution than the temperature.

 

We have built several houses over the years libi g hear and now understand the value of good insulation! 

 

Also the angle the house is to the sun is very important. We have the windows mostly of the sides of the house that get the most shade, and built our outdoor sitting area in the shady side of the house too...which all helps. 

[PatOngo]

35 minutes ago, Pilotman said:

I didn't come here to live in a fridge all day. Just want a cool house, a few degrees below the outside temperature, not a cold one and why spend the money when you don't need to? 

I run the ac 24/7, daytime living room, night time bedroom! Luckily I have one of those with temperature control so I can set it at the optimum temperature and feel comfortable all the time! Hang the expense! 

[EVENKEEL]

We only have A/C in bedroom, looking to replace old style windows with new style sliding glass and install A/C in Living room also for the hot season. As said earlier windows and doors open during the day with floor fans.

[1FinickyOne]

I am in a wide open area w/plenty of breeze, if there is one..

 

hot-hot season, I am a/c whenever I am home... right now, windows open 24/7

 

I will do whatever is needed for personal comfort... 

[GlennSN20U5]

Open door/window and fans on. If you keen on staying outdoor, get a mist water fan. Just make sure it is adjustable.

[potless]

2 hours ago, Pilotman said:

  During the hot days, do I lock the house down, windows, doors and blinds

I suggest keeping some of your windows/doors open for ventilation. Body heat, and  other heat produced by the television, fridge and any other appliances has nowhere to go. In effect creating an oven. A fan assisted one. 

[mr mr]

2 hours ago, Pilotman said:

Having tried both methods I can't decide which is the most efficient in keeping the house coolish.

 

i bet a digital thermometer would help in solving this conundrum. 

[thaisail]

1 hour ago, Crossy said:

Everything wide open with fans and loads of shade plants.

 

Until it gets dark and the Creatures of the Night are abroad at which point we retreat into the A/C.

 

Still enjoying the perfect weather we are having now in CK. When we built this house 6 months ago, we put 2 layers of 2" insulation above the gypsum ceiling. We fitted three ventilation fans in the attic under the unpainted Aluzinc roof that turn on when the temperature sensors up there reach 35 C. We installed 100% opening screen doors in the front and back of the house and all the aluminum windows have screens. There are 3 x 12000 btu double inverter Samsung aircons placed one in each bedroom and one in the living room. The rest of the house will roast with fans this summer. I fitted a 50cm x 50cm screen in the gypsum board above each of the two toilets in each bathroom so that when the fans turn on in the attic, the air is sucked through the bathroom windows and up into the attic to cool the attic. The bathroom windows are always open when it is not too cold. Every hole in the attic has been plugged to prevent egress of any other source of air or other wildlife from entering except for the screens in the bathrooms. So the fans, when on, will draw cool outside air and circulate it under the steel roof. Later when there is a chance, I hope to paint a couple of coats of good heat reflective white paint to keep the fans from coming on too often. 

 

So our plan is to keep the all the windows open with screens closed unless it is too cold like it has been for the past month. We have not used the aircons since we moved in the house in November and have been very comfortable so far. So our air cons have not yet run beyond testing. When do you think we will need to start up the aircons? Will it happen in February or March? We don't have any shade plants yet!

[scubascuba3]

I prefer front door open and balcony door open daytime, mostly get a breeze through, no fans required. Night time same but with mosquito screens plus fan for a few hours until feel cold. When it gets proper hot I tend to put AC on nighttime for a couple hours if condo temperature gets to 27 with humidity around 80%, I set AC at 27 which is probably 1 degree cooler and enough to sleep easy

Edited January 31, 2021 by scubascuba3

[FritsSikkink]

1 hour ago, Pilotman said:

I didn't come here to live in a fridge all day. Just want a cool house, a few degrees below the outside temperature, not a cold one and why spend the money when you don't need to? 

You have temperature control at the AC, got mine at 28, very comfortable. No problems with the outside heat but don't want to be bothered with mosquitos all the time and like it a bit cooler. Money isn't a problem for me. 

[Bangyai]

17 hours ago, CharlieH said:

Depends how much you enjoy all the bugs etc and geckos and god knows what entering the "open house" 

 

I keep it closed everywhere, occasionally open the windows with fans but the windows all have mesh screens to keep out the bugs. Etc

 

Yup, during the day all windows and doors kept closed and curtains drawn half way.

 

The idea is to keep the cool air from the previous night inside as long as possible.

 

If in the daytime it is hotter outside than inside, opening all the doors and windows might well improve air circulation but that will be the hot air from outside blowing through your home.

 

We only keep everything open when it is cooler outside than in.

 

Example , outside right now in the shade of the balcony it is 32.5 C

Inside, buttoned up it is 25 C  without any air con.

 

Another common mistake people make is that more windows make a house cooler ??!!  Windows are a weak point in your defenses not a magic source of cool air.

[sandyf]

2 hours ago, Pilotman said:

I didn't come here to live in a fridge all day. Just want a cool house, a few degrees below the outside temperature, not a cold one and why spend the money when you don't need to? 

You are not going to get the internal temperature below ambient without the help of AC. A draught does not reduce the temperature, just creates a "chill factor" which makes you feel cooler and reduces a build up of internal heat.

To minimise AC use you need to keep the house as close to ambient as possible and this means removing the effect of direct sunlight, natural shade being the most efficient.

As to your original question it depends on the time of year. At the moment I would suggest the best option is to leave as much as possible open for as long as possible. When I built my house I placed the windows to create as many cross draughts as possible. This has been a particularly long winter and we haven't closed the windows for about 3 months and sometimes gone a week without putting a fan on, but that seems to be coming to an end. We close the main door at night but that is wide open from first thing in the morning until bedtime, like the windows the door also has an insect screen.

During the warm weather, almost the reverse, try and keep the warm air outside. I have concrete floors and cavity wall construction so having the aircon on at night keeps the internal temp down during the following day till evening. I appreciate that would not be the same in normal Thai construction so protecting the building from direct sunlight becomes even more important.

The brick work is like a storage heater, absorbs heat from the sun and then gives it back when the sun goes down. The same is true with aircon(negative heat), the bricks will cool and will give out that cool for a period of time, dependent on how exposed they are to the sun.

[sandyf]

1 hour ago, Bangyai said:

Another common mistake people make is that more windows make a house cooler ??!!  Windows are a weak point in your defenses not a magic source of cool air.

Very valid point, but would normally be outside the control of most.

I had relatively small windows put in for the size of the rooms and many may think the house is a bit dull inside, but I can live with that.

[Laza 45]

Depends on how your house is constructed... When I added on to the old house we bought I did cavity walls downstairs.. insulating block outside inside regular concrete block.. verandas shading the walls.. that part of the house I open up at night and close up during the day... it stays cool all day.  The old part of the house .. 1 layer concrete block (rendered).. <deleted> insulation above... is hot no matter what I do.. We open it up in the evening and it is tolerable.. but I would hate to have to spend the day in there.. A rebuild is on the cards for that part.. 

[tonray]

Depends on the relative humidty too. Hot and very wet days...you will be inviting moisture into your house which eventually will lead to mold and once that happens...you'll never get rid of it. You can run the AC to principally dehumidify instead of freezing yourself out. Your house will be better off. When it's dry (winter season generally) open up (with screens of course to keep out mozzies/flys and neighbors annoying kids)...but in rainy season or hot season when it's humid...better off shutting it up.

[Katipo]

I can get a breeze going through mine, so windows open is much cooler. Given current pollution levels though, it's doors and windows closed, with air purifiers and fans or aircon on.

[millymoopoo]

If it's cooler outside than in, open everything, if it's hotter, keep everything closed.

Insulation helps, yes Thai insulation is a bit thin, so double it, it's what we did, it's not that expensive, and installed wall vents for the roof cavity just above ceiling height, and a giant whirlybird on the roof, circulation of air through the roof cavity.

If the roof is red painted or terracotta, get it painted with silver bituminous paint, to reflect the suns heat.

And shade the sun exposed walls too.
Lots of greenery, hanging baskets, lush gardens around the house, watered in the morning.

Passive cooling is way cheaper and better than running the A/C 24/7.

[markeewan]

19 hours ago, Bangyai said:

 

Yup, during the day all windows and doors kept closed and curtains drawn half way.

 

The idea is to keep the cool air from the previous night inside as long as possible.

 

If in the daytime it is hotter outside than inside, opening all the doors and windows might well improve air circulation but that will be the hot air from outside blowing through your home.

 

We only keep everything open when it is cooler outside than in.

 

Example , outside right now in the shade of the balcony it is 32.5 C

Inside, buttoned up it is 25 C  without any air con.

 

Another common mistake people make is that more windows make a house cooler ??!!  Windows are a weak point in your defenses not a magic source of cool air.

Agree, open up at night and then only close the windows and doors once the outside temp is equal to the inside temp. If you have an indoor/outdoor thermometer it is easier to determine when to close up.  I find that in Bangkok I can close up around 2pm and then reopen after 5pm, so the house is only closed for about 3-4 hours during the hottest part of the day. Generally speaking we only use fans inside and air con is not necessary as it does not get above 28C inside.

[thepdru]

24 hours aircon at 29 is so cheap that I still wonder why some people still stop it...

 

[Nemises]

21 hours ago, PatOngo said:

I run the ac 24/7, daytime living room, night time bedroom! Luckily I have one of those with temperature control so I can set it at the optimum temperature and feel comfortable all the time! Hang the expense! 

Ahh yess!....when money is of no concern, would you really tolerate heat, cold, humidity, insects, neighbourhood noise, intruders, air pollution etc or would you have your castle more safer and comfortable with permanently locked double-glazed windows, 24/7 air conditioning (set at optimium level) and air purifiers throughout? 

[PatOngo]

5 minutes ago, Nemises said:

Ahh yess!....when money is of no concern, would you really tolerate heat, cold, humidity, insects, neighbourhood noise, intruders, air pollution etc or would you have your castle more safer and comfortable with permanently locked double-glazed windows, 24/7 air conditioning (set at optimium level) and air purifiers throughout? 

Why would you even consider retiring if money was of concern??? And yes, double glazed windows are great, keeps out the barking dog orchestra! 

[Saltire]

Everything open at dawn till about 3 pm when AC goes on for a nap and the early evening. We have excellent roof insulation so inside during the day is considerably cooler than outside.

 

Aircon in the lounge off at bedtime and AC in bedroom takes over till morning.

 

Love aircon, fans annoy me.

 

1000 Baht per month for electric is a bargain.

 

 

 

 

[AgMech Cowboy]

Open it up in the day. Close it up as soon as you see the 1st mosquito.