Building a house

[Franko]

interesting chat on thermostats. The interesting thing here is that this his one of the areas where tech can save you a clean fortune. there are a few smart thermostats on sale, nest is probably the best branded and owned by google, but there are now a few good ones, and they save you a big chunk on the heating bills. Well worth a look

Pardon the ignorance, but what makes a thermostat smart?

smart would define any device connected to the internet of things. today they reckon theres about 3 billion devices connected and by 2020 gartner predicts there will be in excess of 20 billion connected devices. from phones, tablets, tvs and the like to thermostats, home lighting, home audio, cars, whole houses.....

So what's the advantage with a thermostat, just remote operation?

The thing that makes this stat 'smart' is not it's internet connection (which is a feature), but it's supposed ability to 'learn' your behaviour.  Ie. If you continually turn your heating off/down when going to work, it will learn this behaviour and do it automatically.  If you're always turning your heating up a little over the weekends, or at a certain time of the morning/evening, it will supposedly start to do this automatically.  You also have the iPhone control element.  Seems a bit gimmicky to me but have 2 mates who have it installed in their houses and they swear by it.

[johnneycool]

FFs if i go into my Mums house and put her heating on she grumbles..."i'll have no oil left, that heatings never off...lol". For a laugh i'll turn her stat up to 22 and then next time i go back into house it's back down to 20.5.

I've tried explaining about the benefits of putting the heating on for 3-4 hours instead of boosting it for an hour at a time but she'll not listen...Old School.

We have UFH downstairs and she only boosts it for an hour. I have been telling her for years an hour on UFH is just burning oil. Blast it for 3 hours and you'll get heat off the slab for hours. Never listens!

Ohh and i'm no expert in under ground heating but i was under the impression that had to be on constant to get the benefit of it (obviously not the summer months)

UFH is thermostatically controlled, so as much as its on all the time, the boiler will fire on and off depending on the readings from the thermostats at each particular zone, the boiler isn't firing solidly the whole time.

Yeah obviously Johnney or the above quote wouldn't make sense, I meant it to be on constant but only firing up when it needs too

Surprising how many times I've had to explain that to people in my house asking me why the underfloor heating isn't on and the "I thought it was supposed to be on all the time" and it in the month of August.

I have a Rehau system in and whilst its not internet savy, I can still set up different temperatures at different times of the day depending if anyone is in the house or not.

Some of the internet stuff is just gimmicky.

[macdanger2]

So what are the benefits of having the heat on for 3-4 hours rather than boosting it for an hour?

Ehhhhh, asking for a friend...

Okay...Your boiler is like an oven that heats the surrounding water...when it gets to a certain temperature it will knock itself off, the boiler will then fire up again as soon as the temp starts to drop. When you boost for an hour your boiler will cool way down again so when you decide to fire it up again it's cold and will stay on for ages, if you had kept it on for say 3 hours the boiler will only fire up for a few minutes and know itself off.

Think of it like a kettle, when you boil the water from cold it will take 5 mins but if has just been boiled 5 mins ago and you hit the button on the kettle it will only take 30 sec to boil again as the water is already hot. So for the boiler you can prob enjoy 3 hours of heat for the price of 2no hourly boosts plus you can control it better if you turn the stats down in your house to 20-21 this will also help

I know damn all about plumbing / heating but is the above correct??

From a heat transfer point of view, I would have thought that the fact that hotter water cools faster would mean that it's not correct. For example, say your system heats the water to 70, then switches off until it hits 60 before going backon again . Say it takes 10 minutes to cool from 70-60, 11 minutes to cool from 60-50, 12 minutes from 50-40, etc. Now consider a 4h period where you can either leave it on for X hours continuously or on for the first and third hour only - whatever X would need to be to give you a comparable amount of heat. I would have thought that the fact that leaving it on continuously means that your cooling always happens in the "fastest" zone would mean you use more energy whereas when you let it cool down, the rate of cooling decreases so you should use less.

Is there something I'm missing there?

[illdecide]

So what are the benefits of having the heat on for 3-4 hours rather than boosting it for an hour?

Ehhhhh, asking for a friend...

Okay...Your boiler is like an oven that heats the surrounding water...when it gets to a certain temperature it will knock itself off, the boiler will then fire up again as soon as the temp starts to drop. When you boost for an hour your boiler will cool way down again so when you decide to fire it up again it's cold and will stay on for ages, if you had kept it on for say 3 hours the boiler will only fire up for a few minutes and know itself off.

Think of it like a kettle, when you boil the water from cold it will take 5 mins but if has just been boiled 5 mins ago and you hit the button on the kettle it will only take 30 sec to boil again as the water is already hot. So for the boiler you can prob enjoy 3 hours of heat for the price of 2no hourly boosts plus you can control it better if you turn the stats down in your house to 20-21 this will also help

I know damn all about plumbing / heating but is the above correct??

From a heat transfer point of view, I would have thought that the fact that hotter water cools faster would mean that it's not correct. For example, say your system heats the water to 70, then switches off until it hits 60 before going backon again . Say it takes 10 minutes to cool from 70-60, 11 minutes to cool from 60-50, 12 minutes from 50-40, etc. Now consider a 4h period where you can either leave it on for X hours continuously or on for the first and third hour only - whatever X would need to be to give you a comparable amount of heat. I would have thought that the fact that leaving it on continuously means that your cooling always happens in the "fastest" zone would mean you use more energy whereas when you let it cool down, the rate of cooling decreases so you should use less.

Is there something I'm missing there?

I think so...you forgot when it's on it's only on for 1-2 mins before turning itself off again as it's quickly back up to it's temperature

[macdanger2]

But it takes essentially the exact same amount of energy to heat water by 1C 15 times as it does to heat the water by 15C once. But it will lose the 15 X 1C in a shorter time than it will lose 1 X 15C

[illdecide]

But it takes essentially the exact same amount of energy to heat water by 1C 15 times as it does to heat the water by 15C once. But it will lose the 15 X 1C in a shorter time than it will lose 1 X 15C

Well then in that theory..heat your boiler up to temp, then turn burner off but keep water circulation pump on and it will still circulate the warm water for you...Sorted...

This is just trying to be helpful to some people and i have spoken with Warmflow Heating Engineers regarding this and i'm only trying to explain what they told me, they're the heating experts so i guess they know more than me so i can't put up a reasonable argument against your formula for heat loss. I just fix the dam things when they break and service them when instructed to do so.

[LeoMc]

But it takes essentially the exact same amount of energy to heat water by 1C 15 times as it does to heat the water by 15C once. But it will lose the 15 X 1C in a shorter time than it will lose 1 X 15C

Well then in that theory..heat your boiler up to temp, then turn burner off but keep water circulation pump on and it will still circulate the warm water for you...Sorted...

This is just trying to be helpful to some people and i have spoken with Warmflow Heating Engineers regarding this and i'm only trying to explain what they told me, they're the heating experts so i guess they know more than me so i can't put up a reasonable argument against your formula for heat loss. I just fix the dam things when they break and service them when instructed to do so.

It is like the old question about tea cooling quicker without the milk in it due to the greater temp differential.
For heating the water there should be no difference in approaches but the rate of heat loss will reduce as the water differential reduces.

[manfromdelmonte]

Water is a funny auld substance

Breaks so many of the rules of chemistry

[macdanger2]

But it takes essentially the exact same amount of energy to heat water by 1C 15 times as it does to heat the water by 15C once. But it will lose the 15 X 1C in a shorter time than it will lose 1 X 15C

Well then in that theory..heat your boiler up to temp, then turn burner off but keep water circulation pump on and it will still circulate the warm water for you...Sorted...

This is just trying to be helpful to some people and i have spoken with Warmflow Heating Engineers regarding this and i'm only trying to explain what they told me, they're the heating experts so i guess they know more than me so i can't put up a reasonable argument against your formula for heat loss. I just fix the dam things when they break and service them when instructed to do so.

I wasn't trying to be argumentative. I actually changed the heating yesterday from intermittent to "on" for an extended period as you suggested but then I was thinking about it afterwards and wondering if it was right or not.

[macdanger2]

Actually, maybe the bit about the water circulation pump is what makes the difference - does the pump only run when the heating is on or how does that work?

It could be that by using intermittent heating, most of the cooling of the water happens in the tank (and as such is essentially wasted heat) whereas with leaving it on for an extended period, the water cools by losing heat to the rooms in your house since the pump is running all the time.

[illdecide]

Actually, maybe the bit about the water circulation pump is what makes the difference - does the pump only run when the heating is on or how does that work?

It could be that by using intermittent heating, most of the cooling of the water happens in the tank (and as such is essentially wasted heat) whereas with leaving it on for an extended period, the water cools by losing heat to the rooms in your house since the pump is running all the time.

Normally the pumps are wired up in the boiler house and you will have two switches there, one for the water pump and one for the burner. If it's wired correctly you will need the heating on from the time clock to turn on water pump but dunno if you could be bothered going out to boiler house to manually turn off the switch for the burner...i know i wouldn't.

Lads the oil is very cheap at the min...just whack it on and enjoy the extra bit of heat and your wife/partner will love you for it

[Under Lights]

Looking to get a bit of tarmac around the drive. Tyrone the location.
640 sq.m the area. Looking quotes for Asphalt and Bitumen. Have a couple in but they vary wildly. Also need a bit of ground work done before anything put down. I already have the kerbing done.

Any contacts out there? Average price per Sq.M?

[seafoid]

I read in passive building Ireland that some fella built a 4 bed passive house for 800 euro per square metre. Costs per annum 15 eur. And on RTE someone said Irish people have v low expectations of houses. So many are so cold

[trueblue1234]

I read in passive building Ireland that some fella built a 4 bed passive house for 800 euro per square metre. Costs per annum 15 eur. And on RTE someone said Irish people have v low expectations of houses. So many are so cold

It would want to be cheap to run!!

[blewuporstuffed]

I read in passive building Ireland that some fella built a 4 bed passive house for 800 euro per square metre. Costs per annum 15 eur. And on RTE someone said Irish people have v low expectations of houses. So many are so cold

Do you have a link to the passive building Ireland article?