I have gas-fired CH, via combi boiler, no HW tank. I live in an old (1880's) property (small hall off which toilet, bathroom, kitchen, livingroom off which 2 bedrooms), the upper of two maisonettes. Insulation in the roof, though not to all that high a standard. No insulation in floor, so I get the benefit of heat from downstairs when it's running. Double glazing throughout, one external door not d/g. I have a CH temp control on the boiler (and separate one for HW). It's a non-modulating boiler. Property is quite large for room sizes but sloping ceilings help reduce actual volume, and the rads are well sized for the rooms. No TRV's but programmable room stat located in the hall.
The wall construction is somewhat unknown. I suspect brick for some walls, either brick or brick/timber/lathe&plaster construction for others - it's possible they're just timber/lathe&plaster throughout a lot of the walls but not drilled into them to find out. Internally everything apart from kitchen broom cupboard is drylined/plasterboarded due to condensation/damp being a problem previous to my occupancy.
I'm not about to start adding insulation/upgrading doubleglazing/replacing front door etc, so suggesting I stop more of the heat from being lost in the first place *isn't* a useful OR valid suggestion no matter how well-founded you think it might be.
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.
Turn the boiler temp down, and keep the room stat at a fairly constant setting and just a couple of degrees cooler at night, so that the system is circulating fairly warm water around on a more frequent basis (on the basis that eventually the heat lost from the house will equal the heat the boiler is putting in near enough, with the CH running for long periods with less frequent firing of boiler).
This would presumably avoid having to shove heat back into the walls etc during the heat-up phase in the mornings.
Turn the boiler temp up, and set the room stat to drop significantly overnight, with a blast of heat in the morning, then lower level during the day, then another blast of heat in the evening. This means the place will have cooled down significantly overnight, and the boiler will be working hard to get the place back up to temp in the morning, it'll cool slightly again during the day (I just wear jumpers cos it's easier to regulate my heat with clothes depending on what I'm doing than it is to turn the heating up and down all the time!), heat it back up during the evening again before effectively switching it off over night.
This means the boiler's heating up the fabric of the house twice a day, and then keeping the heat constant.
Now, I originally thought that it was easy to work out, and if the place spent longer not needing to be heated (ie, overnight/during the day if I'm wearing warm clothes) then it worked out more efficient to do the latter, but I'm starting to wonder now.
Heat loss would be the same through the fabric, presumably it'll lose heat faster when the difference between inside and outside is greater, in which case keeping a lower overall temp would be more efficient (and this is actually what I've done already, reduced the room stat by a couple of degrees, which is fine for me).
So do I match the heat loss on a fairly constant level, thus keeping the place heated to a fairly constant level, or do I let the outside suck the heat out of it overnight, then heat the place back up and start maintaining heat in to counter heat loss?
As you can tell if you've stuck with this to the end, I'm a bit confused as to what the best thing to do would be. I've googled and googled both in web and groups to see if this has been discussed and any evidence found on the different ways to keep a place heated, and can find nothing that really explains it, just lots of home energy efficiency tips. I guess I'm looking for an article that explains the physics of heating a home, and looks at the differences between the two ways of doing it.
Any replies will be much appreciated, and thanks for sticking with it if you got this far.