I saw an old thread that mentioned infra red heaters, but i think it
was about a year old and semed to say the heat blows away easily in
the wind.

My pation is quite breezy.

Chris Hogg writes
I've always thought the concept of patio heating to be bizarre and
profligate. Consequently I know little about them, but here are some
thoughts anyway.
I agree, anyone doing this outside in UK on more than the occasional
still and balmy summer night has more money than knowledge of basic
physics.

Infra red (IR) radiation ('light', if you prefer) is like visible
radiation (light). It doesn't blow away. But I can see why air heated
by a bottled-gas heater will. I presume the bit at the top of such a
heater gets red hot and will emit IR radiation. But a large proportion
of the heat will just go straight up and blow away.

The ones you describe as being like floodlights sound like IR units.
IR heating works by warming the surfaces that the IR radiation shines
on. I would have thought they were the better bet for a patio, if you
must.

You have two basic problems. One is getting some heat to you, which is
why the IR type might seem a better bet. But the other is actually
keeping the heat near or on you. On an average UK summer evening you
will rapidly lose most of your comfortable body heat unless you are
insulated by a sweater or some form of insulation. If you don't wear one
then the heat you receive from whatever source will be rapidly lost to
the air around you, and if you have a breezy patio then this will be
significant. It will cost you a lot to continually send heat to you only
to have it whisked away by the breeze.

OTOH if you are wearing insulation then the heat is also going to have
just as hard a time reaching you, as it has to get through the
insulation. You may feel warmer, but the loss to the breeze will be
exactly the same. Its really throwing money away.

Unless you can trap the air in some way, and I mean under a roof as well
as walls like in a closed conservatory, then you will never really
benefit - the warmed air around you will always be swept away. Even on a
still night it will rise - heat does that :-) . In a cold conservatory
you might make enough difference to be able to sit in the evening where
you normally wouldn't, but in any unheated room the heat loss will still
be significant and the improvement only temporary.

I can only think this wonderful con is inspired by pubs which think they
can keep more people drinking if they have these things outside, and the
manufacturers who must be laughing, and the electricity and gas
companies. But it does nothing for the environment and is to my mind a
complete and utter waste of money.

I think I'd stick with jumpers and internal heating using fuel from
another type of bottle ;-)

Exactly. I think this is what the pubs rely on, plus the 'idea' that you
are being warmed by the heaters so you should be OK for another few :-)
--
David