On 2006-12-26 13:15:04 +0000, "Clive" said:

Hi,

I hope to buy a late-Victorian end-of-terrace house sometime in the
new year.

The house is in sound condition - well so it appears and so the
survey says. However, over the next couple of years it will need new
boiler, new bathroom etc. and I am trying to think how to extend into
the loft without it looking like a spaceship has landed on the house.

Now, while I am having work done (by "professionals" (hopefully))
for CH and loft I would like to incorporate as many energy-saving /
energy-generation mechanisms as possible.

I will check all the obvious like quality of insulation and
eliminating damp. However, I would like to find which other "eco"
techniques are effective and have a pay-back of say 10 years or less. I
have thought of the obvious such as some kind of solar panel to
pre-heat water, ground heat collection, water butts, wind generator.
Are there any good Web sites that give "long-term" analyses of these
techniques such as cost of installation and maintenance, effectiveness,
usefulness in SE UK (e.g the amount of "collectible" power form the
wind), reliability etc. etc. ?

Thanks

Clive

The goals may be mutually incompatible.

Having had a house of the type you describe in the past, there are
limits to what
may be achievable.

An end terraced house, especially if it has a rear extension, generally
has a massive exterior wall area
in comparison with the internal area. A depth of 3 to 4 times the
width is quite common.

As a starting point, try to find out about the wall construction -
whether it is solid brick or has cavities.

If you do heat loss calculations (using a calculator program from one
of the CH radiator companies or an on line site), you will almost
certainly find that heat loss through exterior walls is by far the
largest contributor, certainly if the walls are solid.

If the walls are cavity, then insulation in the cavity is a possible
option and will pay back fastest of all, even more so than loft
insulation.

If they are not, then you could insulate them internally with Celotex.
You could use 50mm sheet and make an enormous difference to overall
loss from the building. This would entail losing approximately 75mm
or possibly a little more from room widths,, however, and if they are
already small, may not be acceptable. You could always choose a
subset of rooms, of course. However, ventilation is then even more
important than normal since moisture from the air will tend to condense
on cooler surfaces.

If you can't do something about the walls, then out of the total
heatloss for the house, making substantial improvements in other places
will have a quite small impact on the total.

Heat loss through the loft is normally second after the walls unless
there are a lot of windows. It's reasonable to put in 200-250mm of
glass fibre insulation, or if you are doing a loft conversion,
insulation requirements are stipulated anyway. Again Celotex is
useful because the insulating properties are something like 4 times
those of equivalent depth of glass fibre.

You could do something about the windows, although that will be
restricted if the house is in a conservation area.
If it isn't, then horrible plastic DG units can be used, or there are
wooden framed units that should be in better keeping with the period of
the house. Heat loss through windows is normally third after walls
and an uninsulated loft.

Loss through air changes through floor boards and window frames is
usually significant as well, but again be careful not to try to
hermetically seal the place or there will certainly be condensation if
the walls are not well insulated.

As far as a new boiler is concerned, except in unusual circumstances,
one has to have a condensing boiler anyway, and all have efficiencies
quite close to one another.

All of the above are places where you can make a major difference,
assuming that they are architecturally and economically possible. In
comparison, energy generating schemes such as windmills and solar
panels and alleged saving schemes such as fluorescent bulbs are either
not worth doing or pale into insignificance.

At the end of the day, if you wanted to spend your money on these kind
of generating/saving schemes, you would probably not be buying this
kind of house in the first place because there is a limit on what can
be done to it both practically and economically.

Andy Hall wrote:
On 2006-12-26 13:15:04 +0000, "Clive" said:

Hi,

I hope to buy a late-Victorian end-of-terrace house sometime in the
new year.
snip
If the walls are cavity, then insulation in the cavity is a possible
option and will pay back fastest of all, even more so than loft
insulation.

If they are not, then you could insulate them internally with Celotex.
You could use 50mm sheet and make an enormous difference to overall
loss from the building. This would entail losing approximately 75mm
or possibly a little more from room widths,, however, and if they are
already small, may not be acceptable. You could always choose a
subset of rooms, of course. However, ventilation is then even more
important than normal since moisture from the air will tend to condense
on cooler surfaces.

You only lose 75mm, if there is no internal plasterboarding, or if it's
touching the existing walls.

snip
You could do something about the windows, although that will be
restricted if the house is in a conservation area.
If it isn't, then horrible plastic DG units can be used, or there are
wooden framed units that should be in better keeping with the period of
the house. Heat loss through windows is normally third after walls
and an uninsulated loft.

But...
Taking as an example my house.
It's got 15m^2 of window, in 12 windows.
Under very pessimistic assumptions, this costs maybe a couple of hundred
quid a year to heat, this takes a long time indeed to pay back if new
windows cost 3 grand. (of course, it is possible to DIY reterofit for a
fraction of this, and comfort factors may be important)

Compared to 25mm+12mm of kingspan +plasterboard, over 1/2 of the walls,
that should be the one done first, if at all possible. (and 25mm only if
you are really pushed for space).

snip
All of the above are places where you can make a major difference,
assuming that they are architecturally and economically possible. In
comparison, energy generating schemes such as windmills and solar
panels and alleged saving schemes such as fluorescent bulbs are either
not worth doing or pale into insignificance.

I'd _sligtly_ disagree on energy saving schemes - currently 3 rooms in
the house are lit. With non-CF bulbs, I'd be using 150W or so.
With CF bulbs, I can properly light the rooms, using 50W or so, saving
100W of electricity.
Even if I need to heat at the moment, and neglecting the poor heating
position, that's still a saving of 40 quid a year or better.

IMO - you should first do everything with a short payoff time.
Even if this is only draughtproofing the front door letterbox, and CF
lights.