# Ventilating a 1 1/2 story house.



## Jameshow (20 Jul 2021)

I live in essentially a bungalow with bedrooms in the roof. 

The last few nights have been unbearably hot upstairs and the kids / wife have slept on the sofas in the lounge. (Which are much cooler) 

Anyone have any ideas of cooling the bedrooms in the evening? 

How about a large fan in the window frame say 200mm in diameter? 

Any thoughts? 

Many thanks 

James 

Btw any one finding the workshop too hot too?!


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## Spectric (20 Jul 2021)

You need to install air conditioning, what has happened to when it was normally cooler up North, oh yes global warming. Carries on like this we will be like the tropics and start to grow palm trees and cactus.


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## jimmy_s (20 Jul 2021)

You could do that - night time cooling. Best to use an in line duct type fan and actually blow cool air into the house and allow it to escape via windows etc. Extract fan in window will not work very well as extract has no directional effect. Ideally you would blow cooler air in and duct to ground floor and displace hot air at high level allowing it to escape out windows etc (stack effect vent)


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## artie (21 Jul 2021)

Jameshow said:


> Btw any one finding the workshop too hot too?!


32 c for a while last Sat. Had to search out my bandana to keep my eyes clear.

My house is laid out like yours, but I don't have to go upstairs.


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## D_W (21 Jul 2021)

Put a fan back from the window blowing toward it, about 2 feet. Fans pull air in from the sides, even box fans, which means they pull some from the top corners in the front. Translation, if you put a fan in the window, half or so of the air it pushes is pulled in from outside. 

They'll move twice as much air back from the window because all of the pushed air is originating from inside the house.


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## Inspector (21 Jul 2021)

200mm is not even close to being a large fan. At my last place I used a 760mm/30" 2 speed at the back door to pull air in through all the open windows when I got home from work around midnight. It brought the temp down from 40ºC to whatever the outside temp was at the time in less that half an hour.

I took a 610mm/24" to work to circulate air over me while wearing an evaporative cooling vest. Hung it from a jib crane to get it at chest level. I was the only one to work 10 hour shift and not feel I was melting by the end of it.

You should be looking for something like this at least. https://www.amazon.ca/Lasko-H20610-...ords=30"+drum+floor+fan&qid=1626829518&sr=8-3

Pete


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## JobandKnock (21 Jul 2021)

Spectric said:


> You need to install air conditioning, what has happened to when it was normally cooler up North, oh yes global warming. Carries on like this we will be like the tropics and start to grow palm trees and cactus.


Too late - they already have palm trees in the Kyle of Lochalsh!


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## Aligish (21 Jul 2021)

JobandKnock said:


> Too late - they already have palm trees in the Kyle of Lochalsh!


Not to mention Plockton...!


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## Rorschach (21 Jul 2021)

As @D_W says you need to blow the warm air out, not try and blow cool air in. Big fan blowing out of the upstairs windows and then open the downstairs windows furthest away to get maximum pathway for the cool air. 

Of course this only works if the outside temp is significantly lower than the inside temperature. If that is not the case then you need air conditioning. Portable units can be very useful for the infrequent periods of hot weather we get here, make sure it is an external venting type though with a hose that pumps the hot air outside, otherwise you are not actually cooling anything.


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## Bristol_Rob (21 Jul 2021)

Split ac unit will do nicely.
I've owned one for 20 years and never regretted installing it for the couple of weeks a year it gets used


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## eribaMotters (21 Jul 2021)

James,
I don't think fans are the way forward. You need to think long term on this one. The only real solution will be insulation. We moved into a bungalow end of 2017, that winter we could not get warm and spring 2018 was hot. 400 mm of insulation later and we have no problems. At present we are sleeping without any problems with bedroom window open and winter bills have been slashed whilst house is nice and warm over winter.
Access for the high performance insulation you need may be possible without major work. An old trick used with flat roofs was to remove facia if needed, fold insulation over end of a board and push board up into void. When you pull board out insulation stays in place.

Colin


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## Jacob (21 Jul 2021)

Yes insulation. Also pays for itself in winter.
There's all sorts of traditional passive strategies for cooling houses in desert areas - the most obvious being ventilation arrangements - e.g. a cooling tower which at its simplest is just a chimney. Worth googling.


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## Rorschach (21 Jul 2021)

eribaMotters said:


> James,
> I don't think fans are the way forward. You need to think long term on this one. The only real solution will be insulation. We moved into a bungalow end of 2017, that winter we could not get warm and spring 2018 was hot. 400 mm of insulation later and we have no problems. At present we are sleeping without any problems with bedroom window open and winter bills have been slashed whilst house is nice and warm over winter.
> Access for the high performance insulation you need may be possible without major work. An old trick used with flat roofs was to remove facia if needed, fold insulation over end of a board and push board up into void. When you pull board out insulation stays in place.
> 
> Colin



I get your point, but insulation isn't always the answer. It wouldn't work for me currently, the day time temps are in the high 20's, the night time temps are only a few degrees lower. Insulation will keep that heat out for a day or two but after a week of these kinds of temps the insulation is not doing anything, the inside has reached a pretty much permanent temp of 26-27C now, insulation ain't gonna help there.


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## Jacob (21 Jul 2021)

Rorschach said:


> I get your point, but insulation isn't always the answer. It wouldn't work for me currently, the day time temps are in the high 20's, the night time temps are only a few degrees lower. Insulation will keep that heat out for a day or two but after a week of these kinds of temps the insulation is not doing anything, the inside has reached a pretty much permanent temp of 26-27C now, insulation ain't gonna help there.


Also needs ventilation especially at night when the air temperature is a lot lower and a flow of air is cooler than still air


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## Rorschach (21 Jul 2021)

Jacob said:


> Also needs ventilation especially at night when the air temperature is a lot lower and a flow of air is cooler than still air



Yes indeed, but as I said in my post, the night time air here is the same temp or very close to the same temp as the air inside the house anyway so ventilation does nothing to cool the house.


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## MikeJhn (21 Jul 2021)

A split unit Air source heat pump will cool in Summer and Heat in winter, I have two one in my office and the other in my workshop, would not be without them.


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## Jameshow (21 Jul 2021)

Getting hold of a fan ATM is as easy as collecting rocking horse poop! 

However I had a Eureka moment this morning why not bring in my snail hvlp fan from the workshop. 

Yet to work out how to configure it but worth a good for a couple of hours before bed! 

Cheers James


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## Jacob (21 Jul 2021)

Rorschach said:


> Yes indeed, but as I said in my post, the night time air here is the same temp or very close to the same temp as the air inside the house anyway so ventilation does nothing to cool the house.


If you look at your weather forecast you will see that night time temperatures are nearly always lower (unless the weather itself has changed) and on clear nights can be a lot lower.
e.g. Totnes today - 30º at midday, 20º at midnight
PS


> you need to blow the warm air out, not try and blow cool air in.


Works either way - you can't blow cool air in without blowing warm air out, and vice versa


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## Rorschach (21 Jul 2021)

Jacob said:


> If you look at your weather forecast you will see that night time temperatures are always lower (unless the weather itself has changed) and on clear nights can be a lot lower.
> e.g. Totnes today - 30º at midday, 20º at midnight



Tell that to the weather, last night when I went to bed at 11pm it was 24c outside and when I woke up this morning at 6am it was 22c.

also you will note I did not say the temp at night was the same as during the day, I said it was the same outside as it is inside the house.


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## Jacob (21 Jul 2021)

Rorschach said:


> Tell that to the weather, last night when I went to bed at 11pm it was 24c outside and when I woke up this morning at 6am it was 22c.
> 
> also you will note I did not say the temp at night was the same as during the day, I said it was the same outside as it is inside the house.


That's OK then 22 inside is bearable and will feel lower if there's a draught.
Sorry I forgot your are anti science so weather forecasts and a lot of these things won't mean much to you!


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## Rorschach (21 Jul 2021)

Jacob said:


> That's OK then 22 inside is bearable and will feel lower if there's a draught.
> Sorry I forgot your are anti science so weather forecasts and a lot of these things won't mean much to you!



It isn't 22c inside, it's 27c because the house is already hot, I can bring in some air but it doesn't cool the house sufficiently to bring it back down to the outside temp and we have had no breeze for a week.

Look buddy, you are talking rot as usual, temperatures inside huge thermal stores like houses don't change on a dime when the temp outside falls for a few hours overnight.


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## Jacob (21 Jul 2021)

Rorschach said:


> ...
> I can bring in some air but it doesn't cool the house sufficiently to bring it back down to the outside temp


not enough air


> Look buddy, you are talking rot as usual, temperatures inside huge thermal stores like houses don't change on a dime when the temp outside falls for a few hours overnight.


If you have insulation (in the right places) the inside temperature won't rise so high and if you have enough ventilation it can be brought down to external air temperature. There are other passive measures of course but these are top priority.


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## Rorschach (21 Jul 2021)

Insulation means nothing in prolonged periods of constant temperatures and no active heating or cooling, even you know that.


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## Jacob (21 Jul 2021)

Rorschach said:


> Insulation means nothing in prolonged periods of constant temperatures and no active heating or cooling, even you know that.


Surfaces in sunlight can get very much hotter than the air temperature and if not insulated can raise internal temperature too.


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## Rorschach (21 Jul 2021)

Jacob said:


> Surfaces in sunlight can get very much hotter than the air temperature and if not insulated can raise internal temperature too.



Yep but I am just talking about air temperature. Have a constant average air temperature of 25c for over a week and it doesn't matter how well insulated your house it, the house is stuck at at least 25c unless you have active cooling.

EDIT: Just looked at the actual recorded temperatures for a 24 hour period this week, the average air temperature was 24c over that 24 hours and we had more than 12 hours of constant sunshine so there is an awful lot of solar gain to add onto that. How exactly without active cooling do you propose to get a house down to a reasonable temperature with just ventilation? It isn't physically possible. Insulation will keep out *some* of that solar gain but conversely it will keep in radiated heat overnight making it harder to cool the house.


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## Jacob (21 Jul 2021)

Rorschach said:


> Yep but I am just talking about air temperature. Have a constant average air temperature of 25c for over a week and it doesn't matter how well insulated your house it, the house is stuck at at least 25c unless you have active cooling.
> ......


You won't have had constant 25º for over a week, especially not with clear skies.
Check your local weather reports.


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## Jamesc (21 Jul 2021)

I would suggest you look up passive cooling. Thsi is a very involved subject but the basics are to minimise heat gain during the day and maximise ventilation when the air is cooler. 
As others have said insulation will help, your roof covering will inevitably be a dark material which will absorb heat (just put you hand on the roof or walls after a few hours of full sun). The insulation will help to stop the transfer of this heat into the house. 
Next is solar gain through the windows (think greenhouses), Ideally you want to shade the windows from direct sunlight. This is what the projections you often see on commercial buildins above the windows are for (Google 'brise soleil' for more info). Pulling the curtains or blinds especially if they have a white lining can help.
Finally ventilation. Warm air rises so always try to work with that. if you can create an air path with downstairs windows open on the cool (shaded) side of the house and upstairs windows open on the warm side you will create an natural air flow bringing in cool air. The natural inclination to throw open every window in the house just does not work unless there is a good breeze. The downside to this is the the sun moves so you have to monitor where the sun is falling and adjust your arrangements accordingly. This is why there are many companies out there now selling fully automatic natural ventilation systems. If you are interested one of the bigger players in this country is Monodraught.
Regards
James


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## Terry - Somerset (21 Jul 2021)

Some years ago I suggested to my dear wife it would be very straightforward (power, access etc all easy) to put a split unit AC to service the three bedrooms at the back or the house which get late afternoon and evening sun. 

No - quite unnecessary, I can cope. Regret is not doing it - will be on the list for later this year. 

But a few related thoughts:

meditteranean countries often fit shutters - allow airflow but reduce solar gain - a reasonably cheap fit
I have wondered whether a water spray onto the roof would dramatically reduce internal temperatures through evaporation. This could be a very cheap fix - hose pipe, garden sprinkler, run for 30 mins as sun sets. Any views??
we have tried with some success putting a small fan blowing air into the bedroom (with the bedroom door opento allow airflow) from an open window. This could be improved with a larger fan and ducting to ensure the fan only blows cooler external air in rather than churn what is probably a mix of external and internal air.


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## Jamesc (21 Jul 2021)

Hi Terry,
Your second point is called evaporative cooling and could indeed work. The downside is the risk of Legionella. Evaporative coolers are all but banned for this very reason. Without getting into any kind of debate, Legionella is present in pretty much all water sources, it is only a problem if the concentration gets high (usually stagnent water - think gutters) and the particles are breathed in from a mist of vapour (splashing water from your hose).
It is a small risk but something to be aware of.


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## Adam W. (21 Jul 2021)

The only time this old place gets hot is when it's 36ºC outside for a couple of weeks. So we had the heating on and the woodburner going for a few hours yesterday.

Lovely!


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## Rorschach (21 Jul 2021)

Jacob said:


> You won't have had constant 25º for over a week, especially not with clear skies.
> Check your local weather reports.



Check my previous post, I did the math based on actual recorded temps. Just so you know I added together 24 numbers and then divided by 24, I can do simple math like that


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## Jacob (21 Jul 2021)

Rorschach said:


> Check my previous post, I did the math based on actual recorded temps. .....


In that case your recording methods may want looking at more closely. You should be down to about 20º this evening.


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## Rorschach (21 Jul 2021)

Jacob said:


> In that case your recording methods may want looking at more closely. You should be down to about 20º this evening.



Speak to the MET office, I used their figures.


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## Adam W. (21 Jul 2021)

Now, now boys!

Anyway back to the hot bungalow.

Cooling the exterior of the roof in the evening will not reduce the temperature of the air trapped between the rafters and the ceiling fast enough to reduce the temperature inside the house overnight. So really cross ventilation throughout the upstairs rooms is probably the only solution in the short term.

Reducing the quantity of trapped hot air by filling the void will stop the space heating up, but if the air outside is 26ºC and you open the window, the air temperature inside will eventually increase. Cross ventilation will help by increasing evaporation of perspiration from the skin and I find that a cold shower before bed helps enough to get to sleep when I'm staying in London.

If it's really hot I sleep in a tent in the garden.


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## Jacob (21 Jul 2021)

Rorschach said:


> Speak to the MET office, I used their figures.


You must have misread them. Try again with your own post code/location Wirksworth (Derbyshire) weather


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## Rorschach (21 Jul 2021)

Jacob said:


> You must have misread them. Try again with your own post code/location Wirksworth (Derbyshire) weather



I didn't misread them and I did use the nearest weather station which is only a couple of miles away.


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## RichardG (21 Jul 2021)

You can also use Wundeground to get actual readings from a site nearby. Here’s one in Bradford.

Personal Weather Station Dashboard | Weather Underground

And the temp graphs.










So looking at those with good thermal management (minimising daily heat, maximising even cool) with good insulation I see no reason why the house can’t be kept to a more reasonable inside temp in the low 20s. But it’s an on going process as eventually the thermal mass of the house will reach above the mean outside temperature, but its rare for the U.K. to have prolonged hot nights and days, well at the moment anyway.


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## Rorschach (21 Jul 2021)

Thanks @RichardG for that site. The numbers I calculated from the MET office were actually almost exactly spot on with the numbers provided on that site, within a few 10ths of a degree.


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## Jacob (21 Jul 2021)

Rorschach said:


> Thanks @RichardG for that site. The numbers I calculated from the MET office were actually almost exactly spot on with the numbers provided on that site, within a few 10ths of a degree.


Accuracy and precision are not the same thing. 
Do you in some sort of anomalous zone of steady temperature? Everywhere else in the country gets these big shifts - down to 15º in Bradford! You'd need to keep the duvet on!


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## Jacob (21 Jul 2021)

RichardG said:


> ..... it’s an on going process as eventually the thermal mass of the house will reach above the mean outside temperature, but its rare for the U.K. to have prolonged hot nights and days, well at the moment anyway.


On the thermal mass point - insulation is most effective when it is _at or close_ to the internal surfaces. This reduces thermal mass which means more rapid and better control of heating and cooling. Mine is a chapel conversion but insulated _within_ so the effective thermal mass is just the plasterboard, studs, joists, flooring, room contents. The 100s of tons of masonry construction behind it is not relevant.


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## Rorschach (21 Jul 2021)

Jacob said:


> Accuracy and precision are not the same thing.
> Do you in some sort of anomalous zone of steady temperature? Everywhere else in the country gets these big shifts - down to 15º in Bradford! You'd need to keep the duvet on!



Like I said, take it up with the MET office or Wundeground, my calculations are the same as theirs.


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## Jacob (21 Jul 2021)

Rorschach said:


> Like I said, take it up with the MET office or Wundeground, my calculations are the same as theirs.


I see where you have got it wrong; you say you "Have a constant average air temperature of 25c"
What counts is the range, not the average. There is nothing to calculate.


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## Rorschach (21 Jul 2021)

Jacob said:


> I see where you have got it wrong; you say you "Have a constant average air temperature of 25c"
> What counts is the range, not the average. There is nothing to calculate.



Ummmmm no.


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## RichardG (21 Jul 2021)

Let’s see some figures, this is an interesting and important topic which will effect people more and more in the coming years. I’ve tried to draw on the graph in blue an estimated internal house temperature assuming some insulation during the day and some cooling at night but a I suspect most houses will have a bigger gain than loss as shown so the house will get hotter and hotter.







Certainly my workshop does this, graphs over the last week. Unfortunately the Hottest time is late evening when you most want it cool if it were a house.








So I’d have to minimise the daytime gains by insulation and improve the evening cooling, forced ventilation? May give this a go….


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## MarkAW (21 Jul 2021)

Something I've done which has helped a huge amount is stopping the solar gain during the day. I covered the outside windows on the sunny side of the house.

I imagine that's why many dwellings in continental Europe have shutters on the outside. 

Shutting the curtains helps, but not as much as covering the outside


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## Cabinetman (21 Jul 2021)

@Jamesc has been talking the most sense up to now in both his contributions.
By the way you other two, if everybody else is like me, I am just skipping what you’re saying it’s really boring listening to you two bickering. (Again)


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## Rorschach (21 Jul 2021)

Cabinetman said:


> @Jamesc has been talking the most sense up to now in both his contributions.
> By the way you other two, if everybody else is like me, I am just skipping what you’re saying it’s really boring listening to you two bickering. (Again)



I did try and be useful.


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## Noel (21 Jul 2021)

@Rorschach and @Jacob 
Give this thread a rest, you both have nothing further to add.


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## Duncan A (21 Jul 2021)

Jameshow,
Fans running overnight should help you feel cooler even if they don't directly cool the room down.
There are a number of fans with dc motors on the market which have a dozen or speeds to select from, with some of the speeds specifically selected for quiet nighttime running.
There are a selection here: DC Fans
I bought an Ecoair Zephyr 16" direct from Ecoair and it is virtually silent on the lower speeds whilst still providing a useful and cooling flow of air.
Duncan


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## D_W (21 Jul 2021)

If A/C is the ultimate answer, I agree with the split system suggestion. I had one installed when an exterior seasonal room was made permanent (far cheaper than figuring out ducting through concrete and trying to get adequate cooling from the main system - but cheaper because I didn't' use a mainline dealer to install).

Efficiency of the better splits is incredible.

But for folks who say a fan will never work, it's a matter of what you're used to. First 15 years of my life were in PA in the USA and I slept with a fan. Not sleeping well was rare. One fan set back from the window pushing air out (as long as it's not pushing against the prevailing wind direction) and another light low speed (quiet) fan on the person sleeping and comfortable sleep is had.

it gets far hotter in PA than it does there. Not uncommon to have a week or two stretch with dewpoints higher than you see there and temperatures in the 35C range. Before fans, etc, it wasn't uncommon for people to sleep outside on the hottest days. 

Once you give in to the A/C, it's hard to give it up, though. Splits are more efficient, but above and beyond that, their efficiency advantage over cheaper stuff goes up as temperatures get more extreme. Mine will make 18-20k btu on a 1kw draw at 90 degrees F, despite being rated slightly lower (the cooling rating is at something like 98F or 100F), and it has to get well below freezing before it starts to get inefficient (from drawing another kw for a pre-heat coil) when used for heating.

The unit cost (mitsubishi) was about $2k total for lines and both parts (outdoor unit and indoor head). The local authorized installer wanted $5500 installed to start (installation takes about 4 hours total - plus you need an electrician to install a whip disconnect here, and either you or the electron guy needs to put in a dedicated breaker at an exact amperage - if something goes wrong with the machine, it has to have a limited breaker size so that if it goes bonkers and starts to draw huge current, the breaker trips).

At any rate, the contractor discouraged me from installing it myself, so I paid his HVAC guy $750, and even that guy was hesitant to install for fear of a territory war with the other con jobber who handles the brand.


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## D_W (21 Jul 2021)

(brother in law got a smaller unit than mine from an authorized installer for a screen porch for $6k not that long after - but he's pretty easy to separate from his money).


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## jimmy_s (22 Jul 2021)

Insulation helps quite a lot actually as does thermal mass. Passive solar design involves quite a lot of factors. Ideally though you want to try and keep the heat out in the first place. Insulation results in a lower U value. The surface temp on a roof for example can get very high so insulation reduces conductive heat transfer. Thermal mass can delay peak of energy transfer into building as solar heat transfer is cyclic so mass can cause internal temp increase to occur much later than it would otherwise. Solar gain through glazing is pretty much instant as radiant energy heats internal surfaces and dissipates into rooms. Curtains etc are not that good as heat is already inside so external shutters etc. are best. Also infiltration - if its warmer outside then try to keep doors shut etc. Night time cooling is a low energy cooling strategy as is passive stack ventilation etc which can all help keep temps down.


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## jimmy_s (22 Jul 2021)

Just read your post Jacob - the thermal mass being on the outer face can still help reduce overheating as the thick stone walls may result in the heat taking for example 5 hours to pass through so if the wall is at its hottest at say 2pm the max temp may not reach the insulation until 7pm at which point heat may also be transferred internally and externally as outside temp could be lower than wall temp. Over time the wall may gradually warm up depending on weather conditions etc so effects vary day on day. Lower thermal mass from position of insulation will improve response time of heating generally but even that is impacted by levels of insulation and plant sizing.


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## Doug B (22 Jul 2021)

Jameshow said:


> Btw any one finding the workshop too hot too?!



Quite the opposite it’s so well insulated I have to put my fleece on when I go in there, this is the only time the GLW will be in the workshop as she pops in to cool down.


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## Rorschach (22 Jul 2021)

We actually had a nice cooling breeze last night thank goodness. I managed to get my office under 27C for the first time in days, it's a positively chilly 26.9! lol


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## Lard (22 Jul 2021)

Adam W. said:


> The only time this old place gets hot is when it's 36ºC outside for a couple of weeks. So we had the heating on and the woodburner going for a few hours yesterday.
> 
> Lovely!


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## Woody2Shoes (22 Jul 2021)

An excellent source of coolth is the ground beneath us. A couple of feet below the surface here, the temperature is 8'ish to 11'ish C all year round.

Besides stopping heat getting inside the building envelope to start with, and minimising the amount of energy required to cool the air within that envelope (with insulation and thermal mass and sun shielding (could be as simple as a verandah) - details like people use in the design of their buildings in really hot countries) e.g.



http://www.themajlisgallery.com/wp-content/uploads/2010/07/The-Majlis-Gallery-3-Org-Size.png



I think moving air through the ground before bringing it into the house would be better than air conditioning - like this, perhaps: 









Optimization of operating parameters of earth air tunnel heat exchanger for space cooling: Taguchi method approach - Geothermal Energy


In the present study, CFD-based parametric analysis is carried out to optimise the parameters affecting the temperature drop and heat transfer rate achieved from earth air tunnel heat exchanger (EATHE) system. ANSYS FLUENT 15.0 is used for CFD analysis, and k-ε model and energy equation were...




geothermal-energy-journal.springeropen.com





Of course, the OP doesn't have the luxury of re-designing/re-building their house! Cross-ventilation (both from side-to-side - during the day - and top-to-bottom - at night) and sleeping downstairs are two quick, easy and cost-free solutions.

Don't forget the cooling effects of plants and water too.


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## Jacob (22 Jul 2021)

jimmy_s said:


> Just read your post Jacob - the thermal mass being on the outer face can still help reduce overheating as the thick stone walls may result in the heat taking for example 5 hours to pass through so if the wall is at its hottest at say 2pm the max temp may not reach the insulation until 7pm at which point heat may also be transferred internally and externally as outside temp could be lower than wall temp. Over time the wall may gradually warm up depending on weather conditions etc so effects vary day on day. Lower thermal mass from position of insulation will improve response time of heating generally but even that is impacted by levels of insulation and plant sizing.


I think you are saying that the external thermal mass is a buffer and will reduce the extremes of range of temperatures reaching the inside face?


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## Jameshow (22 Jul 2021)

Thanks for the insights. 

The snail workshop dust collector worked ok but isn't a long term fix. 

How about a fan in the roof hatch and another in the floor under the stairs. That way cool air would be drawn out of the under floor area and drawn up through the building. However this might mean that air isn't drawn out of the bedrooms? 

Cheers James


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## Davey44 (22 Jul 2021)

Surely there's a less expensive and simpler solution? What about creating a substantial air inlet low down on a downstairs wall, ideally north-facing, then leave your upstairs/bedroom windows open. You'll get a flow of cooler air from downstairs though your bedrooms and out of the windows. We have a 1930s 3 bed detached and have a facility to leave downstairs windows open slightly/locked and have two large windows on the landing and of course in each of the bedrooms. We are seldom too hot at night.


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## D_W (22 Jul 2021)

Woody2Shoes said:


> An excellent source of coolth is the ground beneath us. A couple of feet below the surface here, the temperature is 8'ish to 11'ish C all year round.
> 
> Besides stopping heat getting inside the building envelope to start with, and minimising the amount of energy required to cool the air within that envelope (with insulation and thermal mass and sun shielding (could be as simple as a verandah) - details like people use in the design of their buildings in really hot countries) e.g.
> 
> ...



It may be different there than here, but in the states, the challenge in getting at that lower level coolness (it's about 50-55F here) or heat in the winter is getting it without mold and condensation problems. There was an old tradesman on another US forum who described something to me (i didn't completely follow it) as being a pass through of air underground and back up, and he said it worked well. he lives in either VA or TN in the US (both are very hot). 

Challenge 2 is that if too much load is put on a segment or mass of earth underground, it will just come closer to the temp of the air being passed through it. 

I know nothing about geothermal but expect that what happens is the well is drilled, something that will allow the ground adjacent to the well to absorb heat is installed and the piping runs through that (and whatever they require for mass is probably a good starting point for an estimate). 

Or you can go all out as some have done where I grew up and build a house that's actually underground except for the top foot or so. There was one where I grew up - not sort of part of the way underground or built into a hillside, but with all floors underground. The owner said that was a cheaper way to build and own per square foot.


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## D_W (22 Jul 2021)

Jacob said:


> I think you are saying that the external thermal mass is a buffer and will reduce the extremes of range of temperatures reaching the inside face?



This is the case. My parents' home is a summer home from a wealthy quarry owner, so cutting stone isn't an issue. The windows are inefficient (but with storm windows on, they're OK). However, the walls of the house are 16" thick granite and there is some tree cover. 

If you keep the house closed during the day in the summer, temps on the lower floor get above 80F only about 5 days a year in PA, USA. Those days would be bright sun and temps in the upper 90sF. 

I suppose due to the volume of stone that this isn't a particularly economical way to do things, but for a quarry owner, no big deal. I would also suppose that this could be done with something much less expensive than cut granite rock and made even better due to real insulation, which I'm sure their house doesn't have - it's just stone, a small wall space of hardwood 2x4 and lath/plaster.


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## mikej460 (22 Jul 2021)

We live in an old stone cottage with vaulted bedrooms and dubious insulation. The 400 year old part stays cool in summer but the more recent extensions (70s/80s) suffer from heat build up upstairs that make sleeping impossible during a heat wave. We've experimented with lots of different ways of cooling the hotter rooms down and the only thing that works is shutting out the sun during the day then opening all windows and doors front to back once the outside has cooled in the evening. But this depends on air movement and when there is no wind this tactic has little effect. I've now, after 3 nights if broken sleep, bought a portable ac unit from Machine Mart and installed it in our bedroom. It's great.


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## MikeJhn (22 Jul 2021)

People who live in the Med/South of France had it right a long time ago, during the day windows open and shutters closed, hence why the windows open inwards, problem is you walk around in the gloom inside all day, but that should not be a problem as you should be outside, my own place in France has 650mm stone walls and is always at about 20deg under the outside air, even at 40deg externally, the stone just does not seem to heat up.


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## Rorschach (23 Jul 2021)

My office is now under 24C!
Finally had the combo we needed of a prolonged cool period and a decent breeze, the cycle is broken, for now.


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## mikej460 (23 Jul 2021)

Woke up a but chilly this morning and it was still 24C in the bedroom! I guess that despite my complaining about the heat everyday we do adjust..


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## Rorschach (23 Jul 2021)

mikej460 said:


> Woke up a but chilly this morning and it was still 24C in the bedroom! I guess that despite my complaining about the heat everyday we do adjust..



By the time I adjust to the heat it starts getting cold and by the time the cold has stopped making me miserable, spring is around the corner


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## Woody2Shoes (23 Jul 2021)

D_W said:


> It may be different there than here, but in the states, the challenge in getting at that lower level coolness (it's about 50-55F here) or heat in the winter is getting it without mold and condensation problems. There was an old tradesman on another US forum who described something to me (i didn't completely follow it) as being a pass through of air underground and back up, and he said it worked well. he lives in either VA or TN in the US (both are very hot).
> 
> Challenge 2 is that if too much load is put on a segment or mass of earth underground, it will just come closer to the temp of the air being passed through it.
> 
> ...


I think your first point is about managing ventilation - and sources of excess humidity (washing/cooking) - properly.
Re. your second point - yes, apparently Buckingham Palace has a ground source heat pump installed (sounds inappropriate for such a big old draughty pile) but when on full blast can freeze the lake (quicker than it otherwise would)! I think that the answer is about sizing the heat/cool collector appropriately for the application.

Here are a couple of examples from the US using the ground as a source of both heat and cool - collected by cirulating air underground:


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## artie (23 Jul 2021)

mikej460 said:


> we do adjust..


Remember 10 or so years ago we had that really cold spell. It was down to -18 at one point.

I remember going out one morning thinking that's a nice mild one, when I got in the car the gauge said -6


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## Blaidd-Drwg (23 Jul 2021)

Just finished insulating my pole shed and then installed a ductless mini split just in time for two weeks of high 90 degree Fahrenheit "spring" weather. It made a massive difference.


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## Just4Fun (23 Jul 2021)

Woody2Shoes said:


> Re. your second point - yes, apparently Buckingham Palace has a ground source heat pump installed (sounds inappropriate for such a big old draughty pile) but when on full blast can freeze the lake (quicker than it otherwise would)! I think that the answer is about sizing the heat/cool collector appropriately for the application.


We have a ground source heat pump. Our house is no Buckingham Palace but it is a big old draughty pile. When we installed the pump our supplier calculated that the largest off-the-shelf pump they offered would _probably_ be big enough and their solution - rather than opt for a custom build (expensive) - was to put in the standard unit but size the loop in our field to be big enough to support 2 such units, and then put an extra pipe in the trench. The cost of the pipe was small compared to the cost of digging the trench for it. The theory was that if the standard pump proved to be too small it would be easy to install a second pump without having to dig up the field again. We have never needed a second pump, but having an oversized field loop was, I think, a good move. Plus if the field loop were ever to spring a leak we have a second pipe ready to take over.


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## D_W (23 Jul 2021)

Woody2Shoes said:


> I think your first point is about managing ventilation - and sources of excess humidity (washing/cooking) - properly.
> Re. your second point - yes, apparently Buckingham Palace has a ground source heat pump installed (sounds inappropriate for such a big old draughty pile) but when on full blast can freeze the lake (quicker than it otherwise would)! I think that the answer is about sizing the heat/cool collector appropriately for the application.
> 
> Here are a couple of examples from the US using the ground as a source of both heat and cool - collected by cirulating air underground:




I'm such a perv for this kind of stuff that I've seen those before 

I like the buckingham palace story! It still seems to me that in a world without social ridicule, there's something for nothing available in perhaps not totally uniform ways. For example, my house is brick, and the side that gets afternoon sun is partially brick and then a corner is stucco finished. The insulation inside the house isn't so great. There is zero chance that side of the house wouldn't heat all of our domestic hot water with something as simple as a black painted glass covered thermosiphon. The chance that I would ever get away with that is zero, but it would literally reduce the heat load in the house (or in the winter, more efficiently bring it inside) and heat the water, both. 

It's in the blood:




__





Make a Fireplace Water Heater – Mother Earth News


If you know a little about plumbing, you can make this fireplace water heater and capture more of the heat that otherwise would disappear up your chimney. Originally published as "MAKE YOUR FIREPLACE WORK FOR YOU" in the November/December 1978 issue of MOTHER EARTH NEWS.



www.motherearthnews.com





(that's a relative of mine - what's not that well communicated in that article in today's context is that article is 45 years old - once airtight stoves became the norm here, they replaced this setup).


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