Periodically (high fuel prices) these come back out on the market, usually the fan is in the bottom to keep them from getting tippy.

I made one with 4" plastic waste pipe - fan at the top. Worked fine. Don't suppose top or bottom matters too much thermodynamically.

May be better with fan at the bottom regarding the noise (don't know of any musical instruments that work by sucking a pipe rather than blowing, and mine (in a workshop/office) was a bit audibly intrusive).

Took the words right out of my mouth.

GA

I guess it depends on the circumstances. In my set-up, the room had a 2kW convection heater (continuously on), which raised the temperature at ceiling level to about 32°C, while leaving it at about 8°C at ankle level. Adding the fan (20W) evened it out to about 24° up top and 18° down below.

Made life much more tolerable, and the heater thermostat did its job, substantially cutting the heating bill.

The draught from the fan was directed under a bench, where there was nothing to blow around. Any kind of open (i.e. ceiling) fan would, I fear, have blown paperwork all over the place (which tended to happen with cooling fans in the summer).

Never tried it (yet!) but it makes sense to me....

Surely it does not matter too much which way the fan runs, all you want is to mix the air and stop the warm air collecting at the ceiling.....blowing down from the middle must do a good job for summer coolness or winter warmth.....

Hi Andy, If you get the warm air to wash down the windows you relieve the condensation and 'cool-th', so standing near a window or outer wall is more comfortable. The other way just makes a warm spot under the fan, and walls and windows remain cold. Because you're trying to get the cold air to rise in a relitively warm room. Been tried and tested.

My problem is that I have a head full of important trivia, and that I forget the source. (not important/selective memory.)

Carl

I do not understand why that is needed (single pane windows???) with proper double glass windows......they are never cool enough for condensation.

If condensation IS a problem, then new windows are a first priority......

In a normal house where the heating is placed under the windows, the following convection happens:-

With a fan, the warm air near the ceiling will be driven down in the middle of the room, not pushing back on the heating convection, in fact "aiding" it, in the following manner:-

Your winters must be warmer than mine, where -20f is common, (-35f before this warming trend) Furniture is going to disrupt the airflow with a downdraft circulation. Near the floor will remain cold. Get the warm air to wash down the walls for more even temperature.

Warm walls do seem to make the room feel more comfortable - radiation perhaps?

Yes, in a way. Cool-th is the opposite of radiation, drawing heat from the immediate surroundings.

Strictly speaking, what happens is that your body radiates to cold walls but gets nothing back. Warm walls partially return the compliment

How about picking up heat from your attic and pumping it into the living area. Maybe use a filter ahead of you discharge or a heat exchanger?

Nothing new just a thought.

If you have forced air heating such as a central furnace that provides " forced " or fan blown warm air into each room through a floor outlet or " register " as they are called here. You can install cold air return registers in each room that returns the air from each room back to the furnace to be heated again and a closed circuit is formed . This is the new way now as opposed to the old style of having one big return register in the middle of the house to return air to the furnace .

This system design keeps air constantly circulating in each room as the furnace cycles on and off.

If you dont have central heating , a ceiling fan is the way to go.

Warm air heating is not (thank God) very prevalent in Germany, in fact I have never seen one ever here in 28 years...

My Brother (in the UK) removed such a system some years ago after lots of problems, not the least "breathing problems" for people with asthma....innefficient it was too.....!! Cost a Bomb to run and left cold areas all over the house.....you could say "shit installation", but I do not find such houses in the USA to be "comfortable" either....

I was only considering a heating system using radiators, a properly insulated house and double glazing....

A wall is ONLY (nicely) warm if the same wall is really well insulated.....if a badly insulated wall is warm, then a massive amount of energy (cost) is required to achieve that.

That is why it is better to have the warm air from near the ceiling to be blown down in the middle of the room generally speaking as many homes, even today, are simply not well enough insulated to use the other method, without increasing heating costs several %.....or more.....depending upon the insulation factor of the wall(s) in question....

The fan in question needs to be only turning really slowly, so as not to increase the cooling effect, it only needs to mix the lower cooler air with the warmer air.....

In a well insulated house, it does not matter which direction the air takes......the effects are the same....

"The fan in question needs to be only turning really slowly, so as not to increase the cooling effect, it only needs to mix the lower cooler air with the warmer air....."

Right in principle - although there is a minimum - you do need the fan to drive the warm air all the way down to the floor, and with a bit to spare.

On the other hand many people feel more comfortable with cooler conditions if the walls are reasonably warm; whether this results in increased heat loss depends on the insulation of the ceiling and the amount of heat that is lost through draughts.

And the easiest way to set up air circulation is to usually to drive it up (or down) at one edge of the room. There is still no need for a pipe - a fan heater on its edge and with the heat turned off should be more than adequate in most cases - particularly if you use it to assist the air in moving in the direction that it would already be moving.

The human race has warmed itself (except for the last 60 years or less!) by sitting in front of a fire.......(only upper class Romans could afford Hypercausts!), head and front warm, feet and back relatively cold......

There is even a school of thought that feels that underfloor heating, which reverses this dramatically, is responsible for many colds and flu's...... Although it gives a nice warm feeling, its heat up and cool down times are useless for Germany, too many times a cool day follows a warm day.....

Warm air heating has also got a (bad) reputation with many, I dislike it personally too....loud (you hear the fan(s) all over, transfers (private!) sounds all over the house and dries the nasal passages.....

As I mentioned earlier, it strictly depends on the quality of insulation as to what is good and economical and what is not.....

We have insulated our house fairly recently to an extremely high standard, the house was fairly well insulated before, but we have added an extra 10cm on all outside walls and replaced all windows with new double glazing.....it has made a big difference and completely removed the need to blow warm air down from above with any fans.

In the recent January cols spell, we had outside temps down to -27°C, we warm our lounge for example to +22°C, but its on a special timer that a) makes sure that the room is never damaged by frost b) only warms the room when required (evenings only). It turns the heating off at 23:00. Next morning we still have 19°C in there.......

23 years ago when we moved here we needed to spend DM1,800 (€900) per year on gas to keep warm and supply hot water. Today, in spite of massive price rises over all the years, we give out around €450 (DM900) on gas and about €100 on Wood Pellets.....and if anything, my wife likes it warmer in here nowadays than when we first moved in!!

Summer weather does not warm the house up either, it remains temperate all day, we air the house at night in summer for that reason.

There is nothing like a properly insulated house to negate the need for blowing air around.....at least in winter!!!