Should I raise ceiling height & go with evaporative cool

kevin · Feb 10, 2007 9:09 pm

Hi everyone,

I am in the midst of selecting a builder and I am trying hard to see what I can put into my limited budget. One of the options provided by a builder is to raise the ceiling height of the house from 2430 to 2590 mm for $2500.

Are the benefits mainly aesthetic, or are there beneficial reasons to raise the ceiling height?

I have also read another post in this furm discussing between evaporative colling and refrigirated. What do I need to consider (ie. structural changes? piping/wiring?) if I choose to put a split air-con unit after the builder had handed over the keys?

Thanks.

Casa · Feb 10, 2007 9:23 pm

kevin,

Convenient that you mentioned ceiling heights and air conditioning in the one post. One advantage of a higher ceiling is that they are better suited to ceiling fans.

If you can sufficiently thermally insulate your home and have good thermal mass, ceiling fans may be all you need for thermal comfort. Fans use very little power. In the power stakes next comes evaporative cooling, but as other shave mentioned doesn’t work very well on humid days. Air-conditioning is the most expensive to run of the three options.

So, when considering your ceiling height, think about whether you want to include ceiling fans wither now or in the future.

Cheers,
Casa

kevin · Feb 10, 2007 9:51 pm

Thanks for the tip Casa; it's funny how fans never crossed my mind until your reply came.

I made the assumption that ceilings affect the insulation in the house (it's just my 2 cents worth as this is all very new to me). But based on my budget I am trying to also decide the opportunity cost of putting split air-conditioning later. Do you happen to know if this would mean having ugly power cables/water pipes running on the walls? Or maybe further structural changes to be made to the house to accomodate this?

Casa

kevin,

Convenient that you mentioned ceiling heights and air conditioning in the one post. One advantage of a higher ceiling is that they are better suited to ceiling fans.

If you can sufficiently thermally insulate your home and have good thermal mass, ceiling fans may be all you need for thermal comfort. Fans use very little power. In the power stakes next comes evaporative cooling, but as other shave mentioned doesn’t work very well on humid days. Air-conditioning is the most expensive to run of the three options.

So, when considering your ceiling height, think about whether you want to include ceiling fans wither now or in the future.

Cheers,
Casa

Casa · Feb 10, 2007 10:10 pm

The plumbing for split system air-conditioning is quite thin (and so is the power to the units). I would have though that with a little effort both could be concealed. I suspect installers are trying to get in and out with minimal cost so they run the plumbing as quickly a possible.

I think if you talk to an air-conditioning installer about concealed plumbing and electrical they would say it can be done, for a little extra cost. And if you ask them what access you can put in at building time it may be more cost effective.

3timesbuilda · Feb 12, 2007 10:11 am

But based on my budget I am trying to also decide the opportunity cost of putting split air-conditioning later. Do you happen to know if this would mean having ugly power cables/water pipes running on the walls? Or maybe further structural changes to be made to the house to accomodate this?

We put in a couple of splits. If you are putting the unit on an outside wall, there will be no problem, they simply drill a hole in the wall for the piping/wireing to go through. You will then have a single duct on the outside leading to the unit and an emergency switch.

If you are forced to mount on an internal wall, things get a bit more tricky. This is what we had with our second unit. The problem was no really with the coolant pipe or the wireing - they went through the ceiling, but the drain pipe for the condensed water. Water cannot flow uphill so this pipe must be below the unit all the way. Our solution to this was to run through the wall where there was a WIR and run the pipe at the back of that to the outside wall. It wasn't pretty but it did do the job and was not normally visible at the back of the closet behind clothes, boxes etc.

The guy who installed it said that we could go with a pump in the ceiling but that it would cost extra and they have a tendancy to break down. I am curious to know others experiences, our place was double brick with single brick internal walls so to really hide the plumming would have required chipping out the wall, putting in the pipe, filling in the hole, replaster and then repaint AKA $$$$$.

3xb

fmach1 · Feb 18, 2007 12:47 am

I've been looking at evaporative vs refrigerated. The 2 biggest cons on evaporative is that it increases the humidity due to its use of water. Also, it can only reduce the temperature by 10 degrees or so, and can be pretty useless on 34+ days. Two close friends are so feed up with the later, that they have added a split in the main living area to make the day more bareable.

As far as running costs, companys tell you that it costs more to run refrigerated. But you cant compare the results. Ducted or split, refrigerated wins hands down and gives the best result.

Having said that, opt for stuctural upgrades that will keep your house cool while the cooling system is off. ie better insulation, less glass on west facing walls, double pane glass, and anything that can block out afternoon sun from getting through the windows wether it be blinds or shutters.

Cheers, David

fmach1 · Feb 18, 2007 12:47 am

I've been looking at evaporative vs refrigerated. The 2 biggest cons on evaporative is that it increases the humidity due to its use of water. Also, it can only reduce the temperature by 10 degrees or so, and can be pretty useless on 34+ days. Two close friends are so feed up with the later, that they have added a split in the main living area to make the day more bareable.

As far as running costs, companys tell you that it costs more to run refrigerated. But you cant compare the results. Ducted or split, refrigerated wins hands down and gives the best result.

Having said that, opt for stuctural upgrades that will keep your house cool while the cooling system is off. ie better insulation, less glass on west facing walls, double pane glass, and anything that can block out afternoon sun from getting through the windows wether it be blinds or shutters.

Cheers, David

Terry1 · Feb 18, 2007 7:50 am

Hello fmach1,I don't know much about the theory of the two systems but we do have a ducted evaporative system in our house and it works quite well in our climate,which is somewhat like yours I think (very hot summers and very cold winters)The system does lose effectivness on very humid days but they are few and far between here as our heat is fairly dry normally.The unit is cooling a house of 220sq mtrs with nine outlets and we find it handles this alright although some rooms are cooler then others.Insulation and home design are critical to the performance though and alot of consideration went into this when we were planning the house.We have a pitched pergola covering most of one side of our house and other more exposed windows have awnings over them .We also have thick "block out "curtains on some windows and when they are predicting a 40 degree day ahead we usually close these curtains early in the morning and don't let the house heat up.We also have a family room with "raked ceilings"and this room seems to be the coolest of all so as other people were saying higher ceilings do help.Alot of the houses that we work on now are going for 2550mm ceilings.As well as helping the cooling this also gives you more volume in the room and makes it appear bigger I think.In our southern states(usually brick veneer)we are governed by gyrock sheet sizes so the options are 1 1200mm sheet and then 1 1350mm sheet for 2550mm ceilings or 2 1350 mm sheets for 2700mm or 9 ft ceilings.Our West Australian friends don't have this problem as they are usually solid brick.I hope this bit of infomation helps you.Regards Terry

fmach1 · Feb 18, 2007 11:44 am

I do agree that higher ceilings help a lot, but they cause the same problem in winter, that they fix in summer. It takes alot longer to heat the rooms. More points on your cooling probably does help somewhat.

Beaner · Feb 18, 2007 12:22 pm

If you haven't thought about it alreay, you should consider the option of installing 3 phse power with the builder... It will be less than $300....or should be, that's what we were charged and from what I have found out....VERY expensive to fit afterwards.

This will give you the option of fitting the biggest unit (either way) that your budget allows.

Just mt thoughts?

Perth-1st Timer · Feb 18, 2007 8:28 pm

Does ducted evaporative cooling need 3Phase power? I was under the impression that it didn't (only Refrigerative) ?

sneakersss · Feb 19, 2007 9:30 am

Beaner

If you haven't thought about it alreay, you should consider the option of installing 3 phse power with the builder... It will be less than $300....or should be, that's what we were charged and from what I have found out....VERY expensive to fit afterwards.

$300 for 3 phase power? You either got a good deal and I got ripped off or your system and mine differs quite a bit.

Our price for 3 phase underground connection, upgrade of circuit board and isolating switches was $1,100. And then we also had to also had to upgrade/pay for larger ducts.