I've got an ex-authority 4 bed semi in Cornwall, built in the 50's,
heated currently by a single mutli-fuel burner in the lounge which also
has a back boiler for domestic hot water. The hot water tank has a
single 3kw immersion heater in it.
We're looking to put cavity wall insulation in this summer, and I'm
topping up the loft insulation too.
I want to put in some form of central heating, which will also provide
DHW within these constraints:

i. We don't have mains gas
ii. We have limited outside space (I should be able to site an oil tank
OK)

Aside from oil, I've been pondering GSHP, or potentially an electric
boiler combined with solar PV to take the overall sting out of the
electricity bills (I appreciate it's only over the summer I'll be
saving, but every bit helps). We're on a water meter, so we don't tend
to need a massive amount of DHW anyway. We have a ****-poor electric
shower at the moment, which I'm also hoping to incorporate into some
'whole house' solution.

Given that I'm prepared to listen to anything sensible or otherwise,
any suggestions would be great....

Cheers

Rich

"hightower" wrote in message
ups.com...

I've got an ex-authority 4 bed semi in Cornwall, built in the 50's,
heated currently by a single mutli-fuel burner in the lounge which also
has a back boiler for domestic hot water. The hot water tank has a
single 3kw immersion heater in it.
We're looking to put cavity wall insulation in this summer, and I'm
topping up the loft insulation too.
I want to put in some form of central heating, which will also provide
DHW within these constraints:

i. We don't have mains gas
ii. We have limited outside space
(I should be able to site an oil tank
OK)

The easiest is to fit an "outside" oil boiler. Some oil combis are very good
on DHW flowrate. This would eliminate the tanks and cylinders and give high
pressure showers.

You could go LPG, which is expensive to run, but cheap in capital cost to
fit. A Rinnai or Andrews multi-point water heater to do the DHW (they have
amodel that can be fitted on and outside wall "outside") and a small LPG CH
boiler inside for CH.

Aside from oil, I've been pondering GSHP,

They are "very" expensive to fit. You have to do the payback calcs well to
justify one.

or potentially an electric
boiler combined with solar
PV to take the overall sting out of the
electricity bills (I appreciate it's only over the summer I'll be
saving, but every bit helps).

PV panels are not worth it. Direct wet solar DHW heating is cheaper and far
more effective.

You could go thermals store and use overnight cheap electricity to heat it.
It would need to be around 1,000 to 2,000 litres in capacity to take you
through the day in DHW and CH.

The more you insulate and make the house air-tight the less heat you need.
Then once the insulation level gets so high and the heat demand is so low
electric heating become feasible. Less capital cost too.

Initially concentrate on insulating. Can you also externally insulate as
well? Also fit double or triple glazed low "e" glazing and over 1 foot of
insulation in the loft.

On 28 Jun 2006 03:04:41 -0700 someone who may be "hightower"
wrote this:-

Are you aiming to save money in the short term, or are you looking
at longer term investments with an emphasis on reducing your carbon
dioxide footprint?

We're looking to put cavity wall insulation in this summer, and I'm
topping up the loft insulation too.

Don't neglect to insulate the pipes.

Aside from oil, I've been pondering GSHP,

Do you have enough ground to lay the outside coil? They can be
installed vertically, but this is even more expensive as it involves
drilling.

Used with off-peak electricity they can provide a useful input to a
thermal store.

or potentially an electric boiler combined with solar PV

A quick win is to use the sun to heat water. This can be another
input into a thermal store.

(I appreciate it's only over the summer I'll be
saving, but every bit helps).

Solar works in winter too, though obviously at lower output. In
summer a properly designed and installed system should provide
almost all your hot water, in winter it might only provide say 20%.

We have a ****-poor electric
shower at the moment, which I'm also hoping to incorporate into some
'whole house' solution.

Use it as a backup, but have as the main shower either a gravity one
or a venturi one. No need to burn electricity just to pump water.

Given that I'm prepared to listen to anything sensible or otherwise,
any suggestions would be great....

If you want the cheapest electricity bills then shop around, if you
are more interested in carbon dioxide emissions then go for one of
the renewable tariffs from the smaller suppliers. The latter either
offer a rising percentage of 100% from renewable sources (measured
over a year).


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

hightower wrote:
I've got an ex-authority 4 bed semi in Cornwall, built in the 50's,
heated currently by a single mutli-fuel burner in the lounge which also
has a back boiler for domestic hot water. The hot water tank has a
single 3kw immersion heater in it.
We're looking to put cavity wall insulation in this summer, and I'm
topping up the loft insulation too.
I want to put in some form of central heating, which will also provide
DHW within these constraints:

i. We don't have mains gas
ii. We have limited outside space (I should be able to site an oil tank
OK)

Aside from oil, I've been pondering GSHP, or potentially an electric
boiler combined with solar PV to take the overall sting out of the
electricity bills (I appreciate it's only over the summer I'll be
saving, but every bit helps). We're on a water meter, so we don't tend
to need a massive amount of DHW anyway. We have a ****-poor electric
shower at the moment, which I'm also hoping to incorporate into some
'whole house' solution.

Given that I'm prepared to listen to anything sensible or otherwise,
any suggestions would be great....

Cheers

Rich

I'd do some calcs and probably crank up the insulation to get as much
in as space will allow - including between rooms i.e. unused rooms stay
cold. And draughtproofing wherever poss.
You might then find that the high but reduced running costs of all
electric are well offset by the low capital and maintenance costs, esp
if you add in solar heating and source cheap fuel (waste wood) for your
multi fuel. Could you re-direct hot air from the multi?
I'd replace the **** poor shower immediately with a 9 or 10 kw model.
These are quite adequate and cheap to run but not fashionable on this
group - just ignore the adverse comments! And they are always
available whatever the state of the rest of the system.
Don't bother with DG it's a waste of money - do the calcs if you doubt
this. Instead have thick curtains, roller blinds etc.

cheers
Jacob

hightower wrote:
I've got an ex-authority 4 bed semi in Cornwall, built in the 50's,
heated currently by a single mutli-fuel burner in the lounge which also
has a back boiler for domestic hot water. The hot water tank has a
single 3kw immersion heater in it.
We're looking to put cavity wall insulation in this summer, and I'm
topping up the loft insulation too.
I want to put in some form of central heating, which will also provide
DHW within these constraints:

i. We don't have mains gas
ii. We have limited outside space (I should be able to site an oil tank
OK)

Aside from oil, I've been pondering GSHP, or potentially an electric
boiler combined with solar PV to take the overall sting out of the
electricity bills (I appreciate it's only over the summer I'll be
saving, but every bit helps). We're on a water meter, so we don't tend
to need a massive amount of DHW anyway. We have a ****-poor electric
shower at the moment, which I'm also hoping to incorporate into some
'whole house' solution.

Given that I'm prepared to listen to anything sensible or otherwise,
any suggestions would be great....

Cheers

Rich

Two sensible and well tried practical solutions suggest themselves.

(i) Big combi if you don't mind only having one shower and no other hot
water at any one time ;-)

(ii) mains pressure system boiler, pressurised HW tank, and so on.

I don't think the latter is any more expensive than adding a heatbank to
a combi.

With a smallish house well insulated, both will be pretty efficient.


Given it sounds like you are on a tight budget, and don't have a huge
family..the Combi solution sounds most sensible.

"The Natural Philosopher" wrote in message
...
hightower wrote:
I've got an ex-authority 4 bed semi in Cornwall, built in the 50's,
heated currently by a single mutli-fuel burner in the lounge which also
has a back boiler for domestic hot water. The hot water tank has a
single 3kw immersion heater in it.
We're looking to put cavity wall insulation in this summer, and I'm
topping up the loft insulation too.
I want to put in some form of central heating, which will also provide
DHW within these constraints:

i. We don't have mains gas
ii. We have limited outside space (I should be able to site an oil tank
OK)

Aside from oil, I've been pondering GSHP, or potentially an electric
boiler combined with solar PV to take the overall sting out of the
electricity bills (I appreciate it's only over the summer I'll be
saving, but every bit helps). We're on a water meter, so we don't tend
to need a massive amount of DHW anyway. We have a ****-poor electric
shower at the moment, which I'm also hoping to incorporate into some
'whole house' solution.

Given that I'm prepared to listen to anything sensible or otherwise,
any suggestions would be great....

Cheers

Rich

Two sensible and well tried practical solutions suggest themselves.

(i) Big combi if you don't mind only having one shower and no other hot
water at any one time ;-)

There are high flow combis that do more than one shower.

(ii) mains pressure system boiler, pressurised HW tank, and so on.

I don't think the latter is any more expensive than adding a heatbank to a
combi.

Adding a heat bank to a combi achieves nothing as the heat bank can provide
mains pressure DHW at very high flowrates.

Given it sounds like you are on a tight budget, and don't have a huge
family..the Combi solution sounds most sensible.

An oil one.

On 28 Jun 2006 05:19:54 -0700, normanwisdom wrote:

Don't bother with DG it's a waste of money - do the calcs if you doubt
this. Instead have thick curtains, roller blinds etc.

Multiple thick curtains or roller blinds don't help with drafts. Very few
of the energy conservation things have rapid paybacks but are you doing
it for pure economic reasons (smaller primary energy bills) or just to
reduce the amount of energy you consume?

--
Cheers
Dave. pam is missing e-mail

"Owain" wrote in message
...
hightower wrote:

Photovoltaic solar is hard to make cost-effective if you have mains
electricity. Solar water heating may be useful.

I agree with both those points. And solar water heating doesn't just work in
the sun, as we've discovered since January when we installed our own.

Mary

Owain

Thanks for all the responses so far, the general consenus appears to
be:

i. REALLY concentrate on insulation

ii. Oil (no mains gas!!) combi and radiators would be about the
cheapest 'whole house' solution for heating and DHW

iii. GSHP and solar would be a long term investment, but given our lack
of outside space it would need a bore hole +++££££. It'd give us a
nice warm environmentalist feeling inside, but we need to look at the
money side of it for sure Solar water may be worth looking into,
although our need for hot water is lower than our need for heating.

iv. People REALLY seem to hate electric boilers )

We're trying to heat the house efficiently, reduce the carbon footprint
in general, and hopefully make a few long term cost savings too, which
is why I worry a bit about oil. We're too close to other people to go
for other 'green' energy sources, so maybe oil is the most obvious
short to medium term option....??

Thanks again for your time.

Cheers

Rich

In article ews.net,
Doctor Drivel wrote:
A Rinnai or Andrews multi-point water heater to do the DHW (they have
amodel that can be fitted on and outside wall "outside") and a small LPG
CH boiler inside for CH.

So you've moved on from recommending twin combis? What is the next
harebrained scheme you're going to try wasting other's money on?

--
He who laughs last, thinks slowest*

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" through ahze of senile
flatulence wrote in message ...
In article ews.net,
Doctor Drivel wrote:

A Rinnai or Andrews multi-point water heater to do the DHW (they have
amodel that can be fitted on and outside wall "outside") and a small LPG
CH boiler inside for CH.

So

Sad isn't it. I wonder if he has worn out those loafers yet.

On 28 Jun 2006 09:41:20 -0700 someone who may be "hightower"
wrote this:-

i. REALLY concentrate on insulation

Note that there are environmentally friendly forms of insulation, as
well as the "standard" ones. One place to get these is
http://www.greenbuildingstore.co.uk/insulation.php

However, there are limits to what can be done with an existing
building.

ii. Oil (no mains gas!!) combi and radiators would be about the
cheapest 'whole house' solution for heating and DHW

For hot water this depends on numbers, usage patterns, location of
boiler in relation to demand locations and several other factors.
Combination boilers are not the silver bullet that some claim they
are.

If a combination boiler can be located next to the most used hot tap
(the kitchen one) and feed a properly insulated hot water cylinder
next to the place with heavy but irregular use (the bathroom area)
this can be the best of all worlds. However, this is a matter of how
much you wish to re-arrange the house around heating systems.

iii. GSHP and solar would be a long term investment, but given our lack
of outside space it would need a bore hole +++££££. It'd give us a
nice warm environmentalist feeling inside, but we need to look at the
money side of it for sure

http://www.navitron.org.uk/heatpumps.htm is a good place to start on
heat pumps. With no mains gas they can be viable compared to
alternatives, but it depends on the circumstances.

Solar PV is still not a financial investment. Rather it is an
environmental investment to reduce one's carbon footprint and/or
encourage further developments.

Solar water may be worth looking into,
although our need for hot water is lower than our need for heating.

Solar heated water can charge up a thermal store, which is then used
for heating and hot water. These are not cheap, but if starting from
scratch are worth considering. It might be worth having several
large solar panels if they are charging a thermal store.

One of the advantages of a thermal store is that it can take many
inputs. A wood burning stove might be such an input. Are there any
sources of fuel locally?

You might still want an oil fired boiler, but instead of a
complicated combination boiler this would be a far simpler and
smaller one, sized to keep the thermal store charged rather than
heat water instantly.

We're trying to heat the house efficiently, reduce the carbon footprint
in general, and hopefully make a few long term cost savings too, which
is why I worry a bit about oil. We're too close to other people to go
for other 'green' energy sources, so maybe oil is the most obvious
short to medium term option....??

I would build in flexibility. This will be more expensive in the
short term, but will pay back in the long term. Partly this depends
on how long you think you will be in the house.

How able are you to deal with these things? If you can't then
"unusual" systems may be more expensive or impossible to maintain
with local fitters.



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

hightower wrote:
Thanks for all the responses so far, the general consenus appears to
be:

i. REALLY concentrate on insulation

ii. Oil (no mains gas!!) combi and radiators would be about the
cheapest 'whole house' solution for heating and DHW

iii. GSHP and solar would be a long term investment, but given our lack
of outside space it would need a bore hole +++££££. It'd give us a
nice warm environmentalist feeling inside, but we need to look at the
money side of it for sure Solar water may be worth looking into,
although our need for hot water is lower than our need for heating.

iv. People REALLY seem to hate electric boilers )

We're trying to heat the house efficiently, reduce the carbon footprint
in general, and hopefully make a few long term cost savings too, which
is why I worry a bit about oil. We're too close to other people to go
for other 'green' energy sources, so maybe oil is the most obvious
short to medium term option....??

Thanks again for your time.

Cheers

Rich

I think that you have summarised 100% correctly.

Which is encouraging.

David Hansen wrote:
On 28 Jun 2006 09:41:20 -0700 someone who may be "hightower"
wrote this:-

i. REALLY concentrate on insulation

Note that there are environmentally friendly forms of insulation, as
well as the "standard" ones. One place to get these is
http://www.greenbuildingstore.co.uk/insulation.php

However, there are limits to what can be done with an existing
building.


Not on theory there aren;t. You could surround the whole house in 6 feet
of polystyrene if you wanted too..and inject foam under the suspended
floor...use quadruple glazing and heat exchangers in the ventialtion
shafts..;-)

ii. Oil (no mains gas!!) combi and radiators would be about the
cheapest 'whole house' solution for heating and DHW

For hot water this depends on numbers, usage patterns, location of
boiler in relation to demand locations and several other factors.
Combination boilers are not the silver bullet that some claim they
are.


No, but they represent a cheap and effective way of getting reasonably
decent amounts of hot water at mains pressure around a small house..

If a combination boiler can be located next to the most used hot tap
(the kitchen one) and feed a properly insulated hot water cylinder
next to the place with heavy but irregular use (the bathroom area)
this can be the best of all worlds. However, this is a matter of how
much you wish to re-arrange the house around heating systems.


Easier to use a system boiler if you want a pressurised hot water tank.

iii. GSHP and solar would be a long term investment, but given our lack
of outside space it would need a bore hole +++££££. It'd give us a
nice warm environmentalist feeling inside, but we need to look at the
money side of it for sure

http://www.navitron.org.uk/heatpumps.htm is a good place to start on
heat pumps. With no mains gas they can be viable compared to
alternatives, but it depends on the circumstances.

I like the idea of heat pumps because they reduce thermal pollution as well.


Solar PV is still not a financial investment. Rather it is an
environmental investment to reduce one's carbon footprint and/or
encourage further developments.

I think the best way to utilize solar power is to simply have a black
painted preheater for water under glass somewhere. UFH pipe under double
glazing sprayed black?


Solar water may be worth looking into,
although our need for hot water is lower than our need for heating.

Solar heated water can charge up a thermal store, which is then used
for heating and hot water. These are not cheap, but if starting from
scratch are worth considering. It might be worth having several
large solar panels if they are charging a thermal store.

One of the advantages of a thermal store is that it can take many
inputs. A wood burning stove might be such an input. Are there any
sources of fuel locally?

You might still want an oil fired boiler, but instead of a
complicated combination boiler this would be a far simpler and
smaller one, sized to keep the thermal store charged rather than
heat water instantly.

We're trying to heat the house efficiently, reduce the carbon footprint
in general, and hopefully make a few long term cost savings too, which
is why I worry a bit about oil. We're too close to other people to go
for other 'green' energy sources, so maybe oil is the most obvious
short to medium term option....??

I would build in flexibility. This will be more expensive in the
short term, but will pay back in the long term. Partly this depends
on how long you think you will be in the house.

How able are you to deal with these things? If you can't then
"unusual" systems may be more expensive or impossible to maintain
with local fitters.

Dave Liquorice wrote:
On 28 Jun 2006 05:19:54 -0700, normanwisdom wrote:

Don't bother with DG it's a waste of money - do the calcs if you doubt
this. Instead have thick curtains, roller blinds etc.

Multiple thick curtains or roller blinds don't help with drafts. Very few
of the energy conservation things have rapid paybacks but are you doing
it for pure economic reasons (smaller primary energy bills) or just to
reduce the amount of energy you consume?


I agree with both the above. I have SG, and thick lined curtains. Its
warmer than DG and no curtains. However the windows are new, and very
well sealed.

Draughts are the first thing to tackle in any energy saving move. Its
usually cheap, and VERY effective.

Then roof insulation, because its cheap and easy. All the insulation in
a loft is usually less expensive than ONE DG window.

Then walls, because it makes a heck of a difference.

Then floor, because its a big area.

Then and only then tackle those teeny weeny windows that actually
represent a small fraction of the total heatloss area.

"The Natural Philosopher" wrote in message
...
Dave Liquorice wrote:
On 28 Jun 2006 05:19:54 -0700, normanwisdom wrote:

Don't bother with DG it's a waste of money - do the calcs if you doubt
this. Instead have thick curtains, roller blinds etc.

Multiple thick curtains or roller blinds don't help with drafts. Very few
of the energy conservation things have rapid paybacks but are you doing
it for pure economic reasons (smaller primary energy bills) or just to
reduce the amount of energy you consume?


I agree with both the above. I have SG, and thick lined curtains. Its
warmer than DG and no curtains. However the windows are new, and very well
sealed.

Draughts are the first thing to tackle in any energy saving move. Its
usually cheap, and VERY effective.

Then roof insulation, because its cheap and easy. All the insulation in a
loft is usually less expensive than ONE DG window.

Then walls, because it makes a heck of a difference.

Then floor, because its a big area.

Then and only then tackle those teeny weeny windows that actually
represent a small fraction of the total heatloss area.

Gosh! He actually made some sense there. Amazing.

"The Natural Philosopher" wrote in message
...
David Hansen wrote:
On 28 Jun 2006 09:41:20 -0700 someone who may be "hightower"
wrote this:-

i. REALLY concentrate on insulation

Note that there are environmentally friendly forms of insulation, as
well as the "standard" ones. One place to get these is
http://www.greenbuildingstore.co.uk/insulation.php

However, there are limits to what can be done with an existing
building.


Not on theory there aren;t. You could surround the whole house in 6 feet
of polystyrene if you wanted too..and inject foam under the suspended
floor...use quadruple glazing and heat exchangers in the ventialtion
shafts..;-)

ii. Oil (no mains gas!!) combi and radiators would be about the
cheapest 'whole house' solution for heating and DHW

For hot water this depends on numbers, usage patterns, location of
boiler in relation to demand locations and several other factors.
Combination boilers are not the silver bullet that some claim they
are.


No, but they represent a cheap and effective way of getting reasonably
decent amounts of hot water at mains pressure around a small house..

If a combination boiler can be located next to the most used hot tap
(the kitchen one) and feed a properly insulated hot water cylinder
next to the place with heavy but irregular use (the bathroom area)
this can be the best of all worlds. However, this is a matter of how
much you wish to re-arrange the house around heating systems.

Easier to use a system boiler if you want a pressurised hot water tank.

These have an annual service charge. And can do this:
http://www.waterheaterblast.com

Best have a high flowrate combi like an Alpha CD50. it will fill a bath
pronto.

iii. GSHP and solar would be a long term investment, but given our lack
of outside space it would need a bore hole +++££££. It'd give us a
nice warm environmentalist feeling inside, but we need to look at the
money side of it for sure

http://www.navitron.org.uk/heatpumps.htm is a good place to start on
heat pumps. With no mains gas they can be viable compared to
alternatives, but it depends on the circumstances.

I like the idea of heat pumps because they reduce thermal pollution as
well.

Solar PV is still not a financial investment. Rather it is an
environmental investment to reduce one's carbon footprint and/or
encourage further developments.

I think the best way to utilize solar power is to simply have a black
painted preheater for water under glass somewhere. UFH pipe under double
glazing sprayed black?

Plastic pipe. Oh dear.

In message ews.net,
Doctor Drivel writes

Then walls, because it makes a heck of a difference.

Then floor, because its a big area.

Then and only then tackle those teeny weeny windows that actually
represent a small fraction of the total heatloss area.

Gosh! He actually made some sense there. Amazing.

Look and learn

--
geoff

"raden" wrote in message
...
In message ews.net,
Doctor Drivel writes

Then walls, because it makes a heck of a difference.

Then floor, because its a big area.

Then and only then tackle those teeny weeny windows that actually
represent a small fraction of the total heatloss area.

Gosh! He actually made some sense there. Amazing.

Look and learn

Maxie, I looked but never learnt a thing, as there was nothing to learn.
Maxie, do you think the snotty uni one is being redeemed?

On Thu, 29 Jun 2006 00:05:04 +0100 someone who may be The Natural
Philosopher wrote this:-

Combination boilers are not the silver bullet that some claim they
are.

No, but they represent a cheap and effective way of getting reasonably
decent amounts of hot water at mains pressure around a small house..

Indeed. However a four bedroomed demi-detached house may well
necessitate rather more thought going into providing a hot water
service than the "bung in a combi" merchants appear capable of.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On 28 Jun 2006 03:04:41 -0700, "hightower"
wrote:

I've got an ex-authority 4 bed semi in Cornwall, built in the 50's,
heated currently by a single mutli-fuel burner in the lounge which also
has a back boiler for domestic hot water. The hot water tank has a
single 3kw immersion heater in it.
We're looking to put cavity wall insulation in this summer, and I'm
topping up the loft insulation too.
I want to put in some form of central heating, which will also provide
DHW within these constraints:

Maybe your existing back boiler could be configured to run a central
heating system. I'd have thought that would be the cheapest option.

Mark

"Mark" wrote in message
...
On 28 Jun 2006 03:04:41 -0700, "hightower"
wrote:

I've got an ex-authority 4 bed semi in Cornwall, built in the 50's,
heated currently by a single mutli-fuel burner in the lounge which also
has a back boiler for domestic hot water. The hot water tank has a
single 3kw immersion heater in it.
We're looking to put cavity wall insulation in this summer, and I'm
topping up the loft insulation too.
I want to put in some form of central heating, which will also provide
DHW within these constraints:

Maybe your existing back boiler could be configured to run a central
heating system. I'd have thought that would be the cheapest option.

Backboiler? Forget it.

On Thu, 29 Jun 2006 14:43:29 +0100, "Doctor Drivel"
wrote:


"Mark" wrote in message
.. .
On 28 Jun 2006 03:04:41 -0700, "hightower"
wrote:

I've got an ex-authority 4 bed semi in Cornwall, built in the 50's,
heated currently by a single mutli-fuel burner in the lounge which also
has a back boiler for domestic hot water. The hot water tank has a
single 3kw immersion heater in it.
We're looking to put cavity wall insulation in this summer, and I'm
topping up the loft insulation too.
I want to put in some form of central heating, which will also provide
DHW within these constraints:

Maybe your existing back boiler could be configured to run a central
heating system. I'd have thought that would be the cheapest option.

Backboiler? Forget it.

Why? I had a central heating system operating off a backboiler once.
It's not ideal, but it did work.

Mark

"Mark" wrote in message
...
On Thu, 29 Jun 2006 14:43:29 +0100, "Doctor Drivel"
wrote:


"Mark" wrote in message
. ..
On 28 Jun 2006 03:04:41 -0700, "hightower"
wrote:

I've got an ex-authority 4 bed semi in Cornwall, built in the 50's,
heated currently by a single mutli-fuel burner in the lounge which also
has a back boiler for domestic hot water. The hot water tank has a
single 3kw immersion heater in it.
We're looking to put cavity wall insulation in this summer, and I'm
topping up the loft insulation too.
I want to put in some form of central heating, which will also provide
DHW within these constraints:

Maybe your existing back boiler could be configured to run a central
heating system. I'd have thought that would be the cheapest option.

Backboiler? Forget it.

Why? I had a central heating system operating off a backboiler once.
It's not ideal, but it did work.

So you should know better then.

In message ews.net,
Doctor Drivel writes

"raden" wrote in message
...
In message
enews.net, Doctor
Drivel writes

Then walls, because it makes a heck of a difference.

Then floor, because its a big area.

Then and only then tackle those teeny weeny windows that actually
represent a small fraction of the total heatloss area.

Gosh! He actually made some sense there. Amazing.

Look and learn

Maxie, I looked but never learnt a thing,

That's self evident

--
geoff

hightower wrote:
I see there's a lively group of regulars then )
I'm definitely going to go for broke on the insulation end of things,
as ultimately this reduces our need for heating and therefore reduces
our burn of whatever fuel we choose for the CH and DHW.
Is the general consensus that the green sources we COULD feasibly use
in our small plot - solar (for water heating) and GSHP (with bore hole
) may not be worth it?

The idea of solar hot water is appealing, especially given that
Cornwall gets a lot of sunlight, but our need for hot water isn't
massive. Even if we could integrate this with some form of thermal
store which feeds radiators (is this possible?), so that it gives at
least a bit of a kick start to the process of getting water up to
temperature for CH, is it really that practical?

I think so if you DIY it.

As I said, feeding the DHW and CH water through a bunch of black painted
copper pipes under glass on the roof will give you at fair amount of
heat input - even on cold (but clear) winter days..

In summer it probably is enough to heat a tankful to 60C..

I'm prepared to spend whatever I need to, and if this means a big
installation bill and tiny annual costs or a small installation cost
and regular annual outlay then so be it.
As far as I can see, none of the alternative sources make a very good
primary source of heat for both DHW AND CH so maybe a variety of
different approaches would be best?


Solar is great at providing medium amounts of low grade heat - not bad
for things like underfloor heating etc, except that is needed at night,
and the sun shines in the day..so you have to store that heat, which is
not that easy.

Heat pumps are also very efficient if you don't mind freezing the
garden. In cornwall that may be a good bet, as the winter temps are not low.

Another thing if you can bear the hassle is solid fuel or woodburning
stoves..if you have an acre or two of scrub and woodland to carve up
with a chainsaw...you can be almost self sufficient with that. But
carrying wood, cutting it, and ash disposal makes it fairly labour
intensive. You CAN run a back boiler off it too. Needs a separate pump
and primary circuit to integrate with a conventional boiler though.
Gravity feed is sort of OK ish, but its not very efficient. And you need
big pipes.

I don't think solar electric is cost effective, but windpower might be -
in cornwall anyway. If you don;t mind windmills and the like.

If starting from scratch I would probably put in a decent underfloor
heating circuit (that might cope well with low grade solar heat)and a
combi to start with after insulating to the hilt, and then look at ways
of reducing the oil used in the combi by other means as later add-ons.


It does seem almost a crime not to use the 'free' solar input.....


Big windows on south facing walls do that anyway.. IF you can combine
with LOTS of masonry or concrete, you get a good solar input in winter,
and a house that stays cool through the heat of the summer day and warm
throughout the winter night.


There is nothing more depressing than a cardboard box of a house that
needs heat in the evening, and windows open all day to cool it..

If, like us, you actually live in the house 24 hours a day, go for a
well insulated house with a LOT of thermal mass in it.

Our NW facing kitchen is cool in the summer due to the massive chimney
and concrete floors, and toasty in winter when we light the Aga..
...the living room is South East facing and gets loads of sunlight, and
the massive open fires keep the brickwork in the chimneys warm long
after the fire has gone out. and the double insulated curtains keep the
heat IN once the sun goes down..


Cheers again for the entertaining and educational responses.

Rich

On Fri, 30 Jun 2006 13:07:21 +0100, The Natural Philosopher wrote:

Heat pumps are also very efficient if you don't mind freezing the
garden. In cornwall that may be a good bet, as the winter temps are not
low.

A properly sized system (collector area v heat output) shouldn't freeze
the ground. I believe that most of the heat isn't coming from above but
from below. In this country soil temperature varies very little summer to
winter at 1m to 2m depth where a GSHP coil is buried. Though I guess once
you start to pump the heat out you create a temperature gradient and it
will be steeper on the surface side.

I don't think solar electric is cost effective,

Agreed, and the energy costs in producing the PV cells aren't small.

but windpower might be - in cornwall anyway. If you don;t mind
windmills and the like.

Wind is very intermittent, the generally accepted level of output from a
wind turbine ove a year is 1/4 to 1/3 of it's rated output. There are
quite a few small turbines around here and 50% of the time I pass them
they are stationary...

If you have a handy stream and a bit of fall hydro may be worth a look. I
believe there are small systems (ie of the few kW range) available "off
the shelf" in Canada. 24/7 availabilty assuming the stream doesn't dry
up. We only have the fall, no stream, at least not without creating a
reserv... er "garden pond" and storing the available water of which there
is rarely a shortage.


If, like us, you actually live in the house 24 hours a day, go for a
well insulated house with a LOT of thermal mass in it.

Agreed, thermal mass is wonderful, provided you never let it cool down.
The three days it takes this place to warm back up again are
uncomfortable.

--
Cheers
Dave. pam is missing e-mail

Dave Liquorice wrote:
On Fri, 30 Jun 2006 13:07:21 +0100, The Natural Philosopher wrote:

Heat pumps are also very efficient if you don't mind freezing the
garden. In cornwall that may be a good bet, as the winter temps are not
low.

A properly sized system (collector area v heat output) shouldn't freeze
the ground. I believe that most of the heat isn't coming from above but
from below. In this country soil temperature varies very little summer to
winter at 1m to 2m depth where a GSHP coil is buried. Though I guess once
you start to pump the heat out you create a temperature gradient and it
will be steeper on the surface side.

I don't think solar electric is cost effective,

Agreed, and the energy costs in producing the PV cells aren't small.

but windpower might be - in cornwall anyway. If you don;t mind
windmills and the like.

Wind is very intermittent, the generally accepted level of output from a
wind turbine ove a year is 1/4 to 1/3 of it's rated output. There are
quite a few small turbines around here and 50% of the time I pass them
they are stationary...

If you have a handy stream and a bit of fall hydro may be worth a look. I
believe there are small systems (ie of the few kW range) available "off
the shelf" in Canada. 24/7 availabilty assuming the stream doesn't dry
up. We only have the fall, no stream, at least not without creating a
reserv... er "garden pond" and storing the available water of which there
is rarely a shortage.


If, like us, you actually live in the house 24 hours a day, go for a
well insulated house with a LOT of thermal mass in it.

Agreed, thermal mass is wonderful, provided you never let it cool down.
The three days it takes this place to warm back up again are
uncomfortable.

Oh, mine is about 3 hours.,..

On 29 Jun 2006 11:16:41 -0700 someone who may be "hightower"
wrote this:-

Is the general consensus that the green sources we COULD feasibly use
in our small plot - solar (for water heating) and GSHP (with bore hole
) may not be worth it?

Worth it in what terms?

In financial terms, assuming current fuel prices, these things are
long term investments. The same is true of double glazing.

However, as with double glazing, that is not the only criteria to
assess things.

Even if we could integrate this with some form of thermal
store which feeds radiators (is this possible?)

Yes.

While thermal stores are best matched to underfloor heating, some
can produce outputs suitable for feeding radiators.

Consider mains electricity. Would you want all of this to come from
one source?


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Fri, 30 Jun 2006 17:08:20 +0100, The Natural Philosopher wrote:

Agreed, thermal mass is wonderful, provided you never let it cool
down. The three days it takes this place to warm back up again are
uncomfortable.

Oh, mine is about 3 hours.,..

Can't have all that much thermal mass then. B-)

The air gets warm in a couple of hours but several tonnes(*) of cold
stone right through the middle of the house sucking the heat out is very
noticeable.

(*) How much would a rubble built but solid stone wall 18" thick, 18'
high and 25' long weigh? 675 cu feet, 25 cu yards. Is that as near as
damn it 25 tonne?

--
Cheers
Dave. pam is missing e-mail

Dave Liquorice wrote:
On Fri, 30 Jun 2006 17:08:20 +0100, The Natural Philosopher wrote:

Agreed, thermal mass is wonderful, provided you never let it cool
down. The three days it takes this place to warm back up again are
uncomfortable.
Oh, mine is about 3 hours.,..

Can't have all that much thermal mass then. B-)

The air gets warm in a couple of hours but several tonnes(*) of cold
stone right through the middle of the house sucking the heat out is very
noticeable.

(*) How much would a rubble built but solid stone wall 18" thick, 18'
high and 25' long weigh? 675 cu feet, 25 cu yards. Is that as near as
damn it 25 tonne?

About 50 tonnes.

It may be instructive to work it out actually..

I came up with a specific heat of 0.84 Kilojoules per degree C per kg..

So 50 tonnes is 50 Megajoules input for every degree C rise.. so using
wonderful online converters about 13KWh for every degree C rise..

So to raise it ten degrees with a 10KW boiler takes about 13 hours..

That why you need the insulation outside of it..in winter the house here
is extremely stable temperature wise around the masonry..and its the
floor that GETS heated, and the chimneys too..by fires..so the air
doesn't get warm till the masonry is.

The first time I switched the UFH on before the controls had been hooked
up, I left it on overnight..from a dank 3 degrees winter day, the next
morning it was too hot to be comfortable..with a 12KW boiler..I've got
about 30 tonnes of concrete flooring to heat, roughly. 100 sq meters
150mm thick..15 cu meters...35 tonnes appx..yep. Its about right.

I think that really shows that if you have a poured/screeded insulated
concrete floor, there is a huge mass to be heated up, and that in
general use that mass is going to have a very moderating influence on
temperature..and you also have very little to gain by switching heating
off during the day..its simply not going to lose that much heat anyway.

I would say that in summer the average deviation from the diurnal mean
is only about +-2degrees C from late afternoon to sunrise..with the
sorts of temperature around now being 10C by night and 30C by day, thats
20C +- 2 degrees with no heating, but of course there is a fair amount
of heat in the form of people and electrical equipment, so in practice
its a bit higher than that..probably 4-5 degrees.