Ed Sirett wrote:
On Wed, 28 Jan 2004 13:36:56 +0000, Alan Shilling wrote:


----- Original Message -----
From: "Velvet"
Newsgroups: uk.d-i-y
Sent: 28 January 2004 10:01
Subject: CH - most efficient way to run in cold weather?



Snipped

Now, after all that background, the question. Since I'm not out all day
at work, I'm not sure what the most efficient way of heating the place is.

Snipped

Heat loss is proportionate to the insulation factor and temperature
difference between the inside and outside of the house. Hence if you turn
down your thermostat, you will lower the inside temperature and the heat
loss will be less. I'm sure there are small effects due to the way the
boiler performs, but I think the overall picture will remain the same - turn
it down, use less fuel. As you have a programmable thermostat you'd be daft
not to.

In very cold weather, you may need to program the boiler to come on a bit
earlier to get the place warm enough.

The lower the inside temperature, the more heat you'll gain from (or less
you'll lose to) the house below :-)



The least heat lost from the house wil be the regime that runs the lowest
average temperature.
So you need to find what the lowest temperature you're content with for the
night-time (suggest 15C until you know better).
Like-wise anytime you are not there you need you need to find the lowest
temperature you would be happy with considering:
1) The house will take a while to heat up from the low temp.
2) You don't really want the house getting much below 5-10C becasue you
may get temporary condensation on objects with a high thermal mass until
the house is warmed up again.



I keep the house to a fairly normal cycle of heat even when I'm not
there for a weekend (tend not to be gone any longer than that) because I
have pets who, though they'd no doubt survive, would take a while to
acclimatise to lower temps, and then have to acclimatise to higher ones
again - and other pets who will simply end up with their own heaters
running constantly to keep them up to temp. With that in mind, the stat
never sets itself below about 12C at any time day or night, and while
daytimes are cooler than if I'm around, they're still no lower than 16,
with a burst of a couple of degrees of an evening.

My previous experiences with letting a house cool to around 10C is that
it took hours, literally hours and hours, to warm back up again.
Possibly even longer than that - a day, maybe. It wasn't this place so
I'm not sure how much of that was the heating (different system, not
going to start an argument so won't say what it was).


I'm perfectly happy with the stat dropping to 11 or 12 overnight,
because at the moment (well, before this recent cold spell) it's never
got down beyond 14 or so. Me personally I don't mind if it drops below
that, cos I have a thick duvet and prefer a cold rather than hot room to
sleep in. But getting up in the morning I'm conscious of how long the
heating runs for to bring it back up to temperature, vs how often and
long it runs for if it's just maintaining the steady temp.

That's how I got to wondering which one actually does use more gas, and
therefore, costs more... and searched the web, but to no avail, no
concrete examples and theories that demonstrate the differences between
the two methods seem to exist. And whilst I'd give it a go as a home
experiment, I know the weather's too variable to make the results
worthwhile.

Oh well. Ta for the replies. Anyone else?

Velvet