Cooling a house

My house is very hot, especially upstairs. Even with the windows open and a fan blowing it gets hot as the fans just blow the heat round and round the room. What's needed is somewhere for the heat to go.

I was thinking, could I fit small unducted extractor fans in the upstairs ceilings such that they blow the heat directly into the loft? Cooler air would then be drawn in via the windows making the room cooler.

Is there any problem with blowing air directly into the loft in this way? Would it cool the upstairs rooms or make additional problems?

sPoNiX

Reply to
sPoNiX
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The rule in our house when it's hot (as it is today) is to close all curtains on the south side and open doors to allow any moving air to get around.

It works.

Mary

Reply to
Mary Fisher

The hole into the loft space would allow warm moist air to enter in winter creating condensation up there. Try doubling the insulation up there using Rockwool, aim for 250-300mm in total. This prevents heat from entering the rooms below from the baking hot loft. It also keeps heat in, in winter. Then any heat gain in the upstairs rooms will be taken away via through flow ventilation from the windows.

My loft has heavy insulation and the upstairs rooms are far cooler than the neighbours as a result. last August the were uncomfortable at night, while were just right.

Reply to
IMM

We already do that..we also have blackout blinds that we use to prevent the sunlight getting in but it's still too hot. Fans simply circulate the hot air in the room..what I recon we need is a through draft.

I have just spotted these American things:

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look towards the bottom of the page and they seem to vent directly into the loft!

Will there be any problems venting fans directly into a UK loft? I'm thinking maybe one of those bathroom extractors in each bedroom to suck the hot air into the loft.

sPoNiX

Reply to
sPoNiX

First off you should insulate the upstairs ceilings better. This reduces heat uptake from the roof space.

Secondly, yes, if you can find a source of cooler air, suck out the hot and dump it wherever it will leak away - be careful though - if the roof is already hot, pumping hot air into it isn't going to cool the room if the insulation between roof and room is so much garbage.

better to arrange an exhaust pipe outside somewhere.

Reply to
The Natural Philosopher

I hadn't thought that some of the heat could be radiating through the ceiling. I shall take some measurements and see if it's a problem

sPoNIX

Reply to
sPoNiX

Hmmmm:

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"a hefty dose of loft insulation will keep warmth in during summer as well as winter"

Reply to
sPoNiX

If you ventilate it will take the warmth out of the rooms in summer.

Reply to
IMM

That is, of course, why traditional houses in hot countries tend to be single storey.

Put whopping great extractor fans downstairs, to suck the hot air out before it has time to rise upstairs and insulate the loft well, so that heat does not permeate down from the roof.

If you simply want personal comfort, rather than an overall lowering of the temperature, fit ceiling fans above your bed and wherever you usually sit.

Colin Bignell

Reply to
nightjar

We find it effective to open doors/windows on the north side of the house at ground level and the on south side of the house on upper floors. Draughts then tend to flow through the house bringing in cooler air and expelling the hotter stuff.

Nick Broks

Reply to
Nick Brooks

Are these small high speed jobbies or a ceiling fan? Ceiling fans are very effective at keeping rooms comfortable, they set up a a gentle circulation through the entire room not just a little bit of it at high speed.

Well that will bring the warm air from outside in, modern houses have very low thermal mass and are almost hermetically sealed. There is no where for the heat from appliances or the occupants to go. This place just about made 25C inside last August when it was in the low 30's outside. Generally it hovers around 21/22C in the summer. Thats the effect of thick solid stone walls that soak up lots of heat (and also release it in the winter) what you mustn't do it let the place cool down otherwise it takes several days to become comfortable again.

Probably not during the warm spell but I'd be worried about condensation either in the wee small hours or during the cooler periods of the year. Far better to dump the warm (damp) air outside and draw air in from low down on the north side.

Reply to
Dave Liquorice

Good idea, same principle though - ventilation. Free :-)

Mary

Reply to
Mary Fisher

Ceiling fans raise the air temperature around you, but cool you. See...

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Reply to
Andrew Gabriel

Don't put the air in the loft. It could be very humid given the current high temperatures and cause condensation in the loft. Vent it directly outside via the eaves using flexible or fixed pipeing as designed for these fans anyway in bathroom applications.

Reply to
G&M

They are? Er, no they are not. 40% of heat loss in modern homes is via air leaks.

An interpersonal sore in the walls?

In short the heat is stored in the walls. The heat that enters the walls you paid for.

Reply to
IMM

How about getting a box fan, something like:

and putting it in a window in another room blowing air out. Then open the window in your bedroom etc and you will get a cool breeze coming in.

If you can seal off the rest of the window with a blind or something it will help. Alternatively a floor fan is quieter and would shift more air but being round some air will escape back in.

cheers, Pete.

Reply to
Pete C

A perpetual problem, how to cool it. I wrote a pamphlet on this, there are many ways, each of which can take anything from 1 to 10C off the temp. Here's one explained briefly:

External air temp varies through the 24 hour cycle. The sun heats things up, so the max outdoor temp is late afternoon, and the minimum outdoor temp is at around dawn.

Houses have thermal mass, this means they have a tendency to even the temperature variations out over the 24 hours. Therefore at night it is usually colder outside than in, even in summer.

If a house is vented all night long, 2 things occur:

  1. it is cooled
  2. the thermal mass of the house is slowly cooled too, which keeps the house at a lower temp during the following day.

How do you cool a house at night? By fitting locks to windows that allow them to be locked in a slightly open position, enough to ventilate but not enough to allow any means to gain entry. Simple window security bolts can do this: fit an extra one to lock it ajar. Venting is only really effective when you have a through path for the breeze: only one window venting alone wont achieve that much.

Note that venting must occur for quite a long time to really be effective. A house's thermal mass only changes temp very slowly. Opening up for 10 minutes is not going to have much effect.

Regards, NT

Reply to
N. Thornton

I purchased a an air conditioning unit from B&Q. It is an Amcor 12,000 BTU unit with a tumble-dryer type pipe that you shove out of an open door or window.

The unit was on and running today. It turned the room into a fridge.

Superb unit. About £300 though - so not cheap.

However, it is noisy. You couldn't sleep with it on.

Graham

Reply to
Graham Wilson

That was my thought about all the talk about fans - apart from the power use.

Today has been so ennervating that I had to go for a lie-down this afternoon but it happens on so few days a year that I don't think I could be bothered buying a special unit to counteract it. It might happen when I'm not here so it would be wsted. and who wants to be in a fridge anyway?

Just my thought, I'm not trying to convince anyone else.

Mary

Reply to
Mary Fisher

Pardon?

Reply to
Andy Wade

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