# Forum Home Renovation Heating & Cooling  Does insulation really make much difference to temp + power use?

## elly82

We're considering having the ceiling insulated in our house, just with the 3.5 batts, have been quoted just over a thousand dollars to have it done. We live in a single story double brick n tile, in the south of WA. My husband thinks the insulation will provide some ridiculous amount of temperature stability whereas I can't really see that it will. Though I'm happy to have it done of course, and don't think the quote is excessive or anything, just don't want to hear his whinging when it doesn't do what he thinks lol. 
Its currently 12c outside, and 15c inside. So I don't understand how it could make the house any warmer than it is? These are not usual winter temps as those in WA would know, we seem to be having a random cold snap, but the temps will go back up maybe 5 more degrees in a week or so. And the house already stays much warmer than outside at night. Last night was 2c outside and inside it was 11c. So can it really make the house any warmer? 
In summer, we just have the ducted evap aircon which works well probably 95% of the time. We have a handful of humid days per year where it just doesn't work so well but it's livable. However it does seem to use a lot of power. Our bill tripled for the summer months from our usual 1000 odd units up to 3000 units, we only ran the evap maybe 8 hours per day or so, we were told it wouldn't use anywhere near that much power when we had it installed. So maybe the insulation will help with reducing the work load on the evap? But again the evap keeps the temp perfectly fine so I can't see any noticeable temp decrease happening with insulation in summer. 
So I guess in short what I'm asking is what can we reasonably expect from ceiling insulation. 
Also, I have been in the ceiling here twice and there is a single insulation batt in there, just thrown on the ceiling like it has been discarded there. It looks like someone has removed previous batts and just left one behind, why would they remove insulation? Can insulation make the house temp worse in some cases?

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## SilentButDeadly

If the insulation works properly then what it should do is: 
a) smooth out the internal temperature changes in response to external temperatures......basically make it less responsive to external temperature fluctuations. So when it is 2C outside then you may find it finishes up around 15C inside for example meaning you have to put less energy into getting the temp back to a comfortable 18-20 range
b) slow down heating loss (or cooling gain) from any effort you might put in like air-con. 
As for your swampy.....get it serviced.  The only reason that it'll chew more power is that the pump or fan motor has a fault or the belt connecting the fan motor to the fan is failing.  However, there are many other things in your house that chew more power than a swampy.  Refridgeration for instance...

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## Danny

> In summer, we just have the ducted evap aircon which works well probably 95% of the time. We have a handful of humid days per year where it just doesn't work so well but it's livable. However it does seem to use a lot of power. Our bill tripled for the summer months from our usual 1000 odd units up to 3000 units, we only ran the evap maybe 8 hours per day or so, we were told it wouldn't use anywhere near that much power when we had it installed.

  The insulation will definately help in both summer and winter and I am sure that someone will post the technical details for you. It is also easy to install and best done at this time of year. There are also user friendly non fiberglass products that are best used DIY so why pay somebody to install it?  
Evap air cons use less power than alternative types but will still use lots of power if run for long periods; however, there is one other thing that you really need to consider. Your State, W.Australia, has serious water shortages and the average evap air con uses about 60 litres of water per hour. For your posted average running time per day, this is nearly 500 litres per day! Your social consience should dictate that you reduce this. By insulating and perhaps installing some efficient ceiling fans (check other threads), you will save on energy and water costs.

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## sundancewfs

Insulation won't make your house warmer...... Heating the house will do that. Insulation will help keep that heat in the house. This means you shouldn't have to heat as much to keep the inside at a comfortable temperature. As with all things, its never really any one thing that will end up giving the best results. Think of the house as a closed box. By controlling your inputs (heating in the winter and aircon in the summer) you have control over your comfort levels. Insulation is measured as an R value. This is really a measure of resistance, for example in winter it slows the speed at which your warm,heated air is escaping. In the summer it slows the heat for direct sun on the roof making its way into the interior of the house. Hence in general the higher the R value the better. Some of the most important other things to consider in the mix are, stopping drafts, external window shading and reflective insulation. The way the insulation is installed is of the utmost importance too. Leaving gaps during the installation is not good as it will reduce the efficiency of the insulation dramatically. If you have downlights the presents another problem as the insulation MUST not be placed right up to the lights or transformers as it creates a huge fire risk. There are heat shrouds that should be considered for any insulation installation where downlights are present. My personal opinon is, you can't have too much insulation. I have one layer of R5 batts with another layer of R4.1 batts laid perpendicular to the bottom layer, plus R2.1 reflective Aircell insulbreak under the tin. Does it make a difference? Yes. Ceiling surface temperatures in summer ran to about 50 deg c without insulation. Now they measure the same temperature as the air temperature in the room, ie, if the room is 24 deg c, the ceiling temperature is 24 deg c. For the most part the southwest of WA is fairly mild. On the coast, say, Margs etc you have the maritime climate and sea breezes. Further inland around Nannup, Pemberton way its a bit colder in winter and a bit warmer in summer. I think you will be pleasantly suprised by the insulation, but don't expect too much. R3.5 is very much a minimum value to use...... Good luck.
As a bit of background I grew up living around the Walpole, Denmark, Albany area and spent many years living in areas like Margaret River and even further out in places like Darkan.

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## sparker

We had our roof insulated at Mackay Qld. It was done by professionals using batts. The house is a two-storey brick home with a trim deck roof. It has been renovated but is about 50 years old. I hate being negative but for the life of me I can't tell any difference in living conditions inside the house after the insulation was done a couple of years ago. I know the science behind insulation is correct....perhaps I expected too much.

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## SilentButDeadly

Social conscience?   
I'll see your 500 litres of water and raise you about 8 kilowatt hours of extra electricity consumption for refridgerative air-con over a swampy over an eight hour period. It may be swings and roundabouts but where's the social conscience in that?   
That said....I'm with you.  Ceiling fans and good cross ventilation will save you from all kinds of air conditioning for a considerable part of the year

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## Moondog55

Insulation can make a house worse in some very unusual circumstances, such as having very large windows that get full sun all day, and not doing things correctly like shade the outside walls and forgetting to put sunblinds on the outside of the windows so all the heat gets trapped inside, but that would involve doing EVERYTHING wrong. Part of your problem is the construction of your house, tiled roofs soak up the heat during the day and at night they radiate that stored heat half to the sky and the other half downwards into your home. the brick construction of the house does exactly the same thing.
Retro fitting reflective insulation ( sarking ) would be of benefit if it isn't there already.
Insulation is part of a package of measures we need to take, stopping solar radiation from hitting the house is part of that, so as well as the insulation you need to shade the walls and window; keep the heat out in summer is rule #1.  Your Home Technical Manual - Home Page 
Lots of pertinent and valuable information on insulation and passive cooling in the site

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## Danny

> Social conscience?   
> I'll see your 500 litres of water and raise you about 8 kilowatt hours of extra electricity consumption for refridgerative air-con over a swampy over an eight hour period. It may be swings and roundabouts but where's the social conscience in that?

  S.B.D. 
If you carefully read what I posted, you will understand that I was not advocating the use of refridgerated air con over evaporative.  
Despite nearly 100 mm of rain over the last 4 days, WA's dam levels have only increased from 22.8% to 23%. Their water storage situation is critical. A lot of people do not realise how much water an evap air con uses. That is why I advocated insulation and efficient ceiling fans. 
I would have thought that any encouragement for someone in W.A. to reduce their high usage of evap air con PLUS reduce their energy demand would be viewed positively.

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## mcsmart

> We had our roof insulated at Mackay Qld. It was done by professionals using batts. The house is a two-storey brick home with a trim deck roof. It has been renovated but is about 50 years old. I hate being negative but for the life of me I can't tell any difference in living conditions inside the house after the insulation was done a couple of years ago. I know the science behind insulation is correct....perhaps I expected too much.

  I thourogly recommend you and elly82 take Moondog55's advice and look at that website, even buy the book.  When I was in there it took me a while to work out that most of the sections can be expanded for further information.  Its development was a great initiative.  The government has copped a spanking over insulation and etc but they did a great job on this.  Hope I have not started something here.........

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## elly82

Thankyou for all the info and I will have a read of that site too. 
The aircon is working properly as far as I can tell and it was only installed last year in September so it's only seen one summer so far. It's obviously not being used at all now and we intend to have it serviced sometime in this winter period in preperation for the summer, each year. I think we actually get 2 free yearly services with it to start with. 
Just to reply to the water issue, I have actually been pleasantly surprised at just how little water this aircon uses. Even with the power bill tripling the water bill only increased slightly and is still well under our area's average. In fact our bill says our usage is even less than the average with bore, while we do not have a bore. So it can't be doing too badly there. Water was a concern of mine, having lived out in the wheatbelt before, and having family still running farms there I know only too well about the drought issue.

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## phs

Ill put it plain and simply . doing your insulation will Save u heaps in heating and cooling bill. Provided u have good heating and cooling installed in your house ie. Inverter split system cooling, gas ducted , any form of hydronic heating or solid fuel heating.  
Iv worked on new houses with wall insulation roof insulation and double glazed windows. And they hold there inside temp. Very well.  
Well worth the dollars insulating

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## Moondog55

@phs
I have to say again ONLY as part of the whole, if you don't have the summer sun excluded, eaves on the roof to shade the walls from the noon sun and all the leaks fixed and drafts stopped; insulation is part of the whole package when we are talking about keeping the house cool. 
Ceiling insulation tho is the biggest step to winter comfort we ever took, and I don't think the minimum standards are high enough

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## Danny

> I have actually been pleasantly surprised at just how little water this aircon uses. Even with the power bill tripling the water bill only increased slightly and is still well under our area's average. In fact our bill says our usage is even less than the average with bore, while we do not have a bore.

  Your greatly increased energy consumption is unusual as noted earlier by S.B.D. Also unusual is your stated low water usage. If you live in a hard water area, it is possible that the pads have built up mineral content that is effecting their flow through efficiency. There may also be other causes. The decreased efficiency would lessen water use and increase power usage but your huge power increase is not normal. The good thing is that your service will be free!  
There is a lot of information available regarding evap air cons. The link below is credible.  http://www.derm.qld.gov.au/water/reg...nditioning.pdf

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## elly82

Could it really build up that much minerals in only 4 months of use? We don't have particularly hard water here at all. It was installed in Sept but not even used until November, then through to end of Feb. I'll have them look when the service is done anyway, but hopefully it is just more water efficient than some.  
The installer did instruct me to skip the pad washing if turning it on more than once in a day, so that probably saves some. It washes the pads automatically when you turn it on then dumps that water. He said if I turn it on, let it wash, then turn it off and go out then come home and turn it back on that it's not necessary to rewash the pads then and to skip that to save on water so I was doing that, but it was still washing the pads once a day when we used it, I don't know how much water it uses to do that.  
We don't use much water with our other appliances anyway. We had both toilets replaced with water saving ones when we moved in. I use the dishwasher and washing machine both on eco-setting mostly (not so good for heavily soiled dishes or clothes, but this is not often in our house). We bath the two smaller children together, and as much as I'd sometimes love a long shower we have a crap storage hotwater system which forces me out soon enough anyway lol. So I guess all that keeps us under the average even with the aircon, given I see neighbours here still watering their lawns daily in winter that may not even be such a difficult goal anyway.  :Roll Eyes (Sarcastic):  
The power issue is an odd one anyhow, as I mention we used the aircon for the 4months. Here we get power bills every 2 months. The November/December bill was the one that tripled. The Jan/Feb bill was not as high as the previous one, still higher than normal but a more acceptable bill and what I sort of expected. This is odd as WA people will remember we had a horrible heat wave in Feb and the temps then were definitely worse than the Nov/Dec period, so I would have expected any excess power usage to be in that time. It will be interesting to see what sort of bill next summer produces. 
We have decided to go ahead with the insulation, we were quoted for R3.5 batts, but are going to check out the price difference with other kinds first too. We've also decided to do something about the flooring throughout the main part of the house. At the moment it is just tile, and they are laid directly on the cement slab, so they get very cold. So we'll be looking at replacing that with some sort of underlay and perhaps vinyl or laminate. Would love timber but don't think the $$ will stretch that far.

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## Danny

Perhaps your water saving initiatives have disguised the evap air con water use. The bleed off (water dump) for newer units is generally 10-15% of the overall water use. The dump is to remove the build up of minerals and salts due to the evaporation. Many older units use to dump around 12-15 litres but the newer ones generally only dump about 4-6 litres. Skipping dumps might save a little water but when compared to the overall water use and the importance of the bleed cycle with low volume discharges, is it worthwhile doing so? 
Evap air cons are simple devices and if you mention the power spike and possible low water use to the service man, he will soon find if something needs adjusting.  
Re cold tiles, this would be a blessing in summer; you could buy a big rug(s) to lay over the tiles in the colder months. This is generally more cost effective than replacement of tiling and most often more stylish.  
Re power bill, is it possible that your high bill was an estimated reading? I was overcharged $470 on an estimated reading about 3 years ago!

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