OT: Does Opening Loft Hatch Help to Cool a House

Sometimes told me that opening the loft hatch can help to cool a house down in hot weather. Is this true or an old wives' tale?

I gave it a go & wasn't sure if it was helping - if anything pretty warm air seemed to be coming down from the loft.

Is it something that you only do at night?

Regards,

Michael

Reply to
michaeld121
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I tried it and on hot days it seemed like there was a heater blowing hot air down into the house. Now I only do it at night, if at all, or use a fan so that the air only flows into the loft (clearing the stored hot air)

Reply to
adder1969

The message from snipped-for-privacy@hotmail.com contains these words:

It works for us - it'll depend on how the air flows through your house as to whether it makes a difference.

Actually, ours /usually/ works but not always. I was thinking last night of fitting a socking great fan to a dummy loft-hatch for hot nights.

Reply to
Guy King

I tried that the last time we had a heat wave - Huge's Patent Extractohatch! I can't say as it appeared to make any huge difference.

What *has* made a difference is putting a "light stop" blind up in my study - an opaque white roller blind, to reflect the sun back out.

Reply to
Huge

On 26 Jul 2006 07:11:17 -0700 someone who may be snipped-for-privacy@hotmail.com wrote this:-

The answer is, it depends on the situation. For instance, does the roof have an opening skylight?

Reply to
David Hansen

The message from Huge contains these words:

I had a few square meters of reflective bubblewrap left over so I made a sunhat for the conservatory. The ceiling went from being too hot to touch to body heat, which combined with an old sheet strung out to shade the windows has made working in there tolerable with a fan.

Reply to
Guy King

Where I am it's something you would only even attempt at night. Between about 9AM and 8PM the outside air temperature has been significantly higher than inside for the last few weeks.

In theory it should work, as lofts are ventilated and convection should pull cooler air into the house. In practice, as you and others have said, the hot air seems to fall downwards out of it. Possibly with an open window high in the roof it might work.

Reply to
Joe

Nope - no skylight. It's in an Edwardian semi and the loft gets very hot during the day. There's reasonable insulation between the loft and the first floor.

I'm interested to see that someone else seemed to find hot air coming down from the loft, which isn't really what you'd expect.

Michael

Reply to
michaeld121

snipped-for-privacy@hotmail.com wrote in news: snipped-for-privacy@m73g2000cwd.googlegroups.com:

I tried it too, and it was like the others' experience - blast furnace air bowing down.

I put the hatch back PDQ :-O

mike

Reply to
mike

British lofts get very hot and have no ridge ventilation, so opening the hatch will just feed hot air into the house. If the loft had generous ridge ventilation, it just might work, but theyre not like that here.

NT

Reply to
meow2222

!!!DON'T!!!

Extraordinary how many people seem totally ignorant about this, I posted about it in another diy ng just a couple of days ago ...

Most lofts have exposed insulation on top of the bedroom ceilings, and are full of dust from the rock-wool that it's made from. This dust is a serious health hazard - it can cause lung and skin damage.

Always don a mask before opening the loft, and wear gloves when handling the insulation.

Reply to
Java Jive

It is exactly what you should expect. The ventilation of most lofts is at loft floor level on both sides. Any slight breeze generates overpressure in the loft and pushes hot air down through the line of least resistance - the open hatch. Even with normal ridge ventilation the area of the ridge escape is so small the same effect occurs.

Reply to
Peter Parry

Only if the loft is cooler than the house..which is almost always not the case in summer, with an insulated ceiling, and a loft exposed to the sun on its roof.

In our house, which has a lot of concrete in it and brick chimneys, the coollest thing is to shut all the windows apart from trickled ventilation, draw the curtains and hudddle by teh Aga...which is (off) maintaining a steady 25C day and night...

At night we open all the windows, as the outside is now cooler than inside.

Reply to
The Natural Philosopher

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