heating calculations
 

I'm in the process of buying a couple of multifuel burners for our two
downstairs rooms and need to work out what heat output I should be looking
for (in KW).

One room is about 15' by 26' with a low (6'2" ceiling)

The other room is about 15' by 29' with an 8' ceiling

Can anyone tell me the formula and if anyone is selling a multifuel burner
then let me know.

Thanks

D

PS the house is a timber framed wattle and daub affair :)

I'm in the process of buying a couple of multifuel burners for our two
downstairs rooms and need to work out what heat output I should be looking
for (in KW).

The main problem is getting a reasonable u-Value for wattle and daub. Once
you've got that, the calculation is simple. Anyone like to suggest one? To
me, it sounds like it would insulate better than brick.

Also, is the room draughty? Presumably small windows? Are they well fitting?
How many outside walls in each room?

Christian.

"Christian McArdle" wrote in message
. net...
I'm in the process of buying a couple of multifuel burners for our two
downstairs rooms and need to work out what heat output I should be
looking
for (in KW).

The main problem is getting a reasonable u-Value for wattle and daub. Once
you've got that, the calculation is simple. Anyone like to suggest one? To
me, it sounds like it would insulate better than brick.

Also, is the room draughty? Presumably small windows? Are they well
fitting?
How many outside walls in each room?


The rooms are pretty draughty, smallish well fitting windows mostly
secondary glazed with 6mm glass.
The smaller room has one and a half outside walls along the long edge, the
larger room has three outside walls along both long edges and one short
edge, it also has two external doors.

Thanks

David

The rooms are pretty draughty, smallish well fitting windows mostly
secondary glazed with 6mm glass.

Currently, using 1.5 as a uValue, assuming warm rooms above and besides and
designed for -3C outside, I estimate.

3.3kW for the small room.
5.5kW for the big room.

This is allowing 3 air changes rather than 1.5 to allow for draughts.
Also, I strongly suspect that wattle and daub will provide better than 1.5
uValue.

If, for example, you managed to fix the draughts and have a normal level of
ventilation and the uValue turned out to be 0.8, you would get

2.1kW for the small room.
3.2kW for the big room.

Christian.

Christian McArdle wrote:

I'm in the process of buying a couple of multifuel burners for our two
downstairs rooms and need to work out what heat output I should be looking
for (in KW).


The main problem is getting a reasonable u-Value for wattle and daub. Once
you've got that, the calculation is simple. Anyone like to suggest one? To
me, it sounds like it would insulate better than brick.

Also, is the room draughty? Presumably small windows? Are they well fitting?
How many outside walls in each room?

Christian.


wattle and daub is very similar to (thicker) plasterboard: Key is the
air gap/cavity, which should be filled with insulation.

Typical timber frame I have seen is lath on outside rendered (should be
lime mortar, most these days been upgraded with DPM chicken wire and
cement coat), air gap (mouse runs?) then hazel lath and daub over.

The rooms are pretty draughty, smallish well fitting windows mostly
secondary glazed with 6mm glass.

Currently, using 1.5 as a uValue, assuming warm rooms above and besides
and
designed for -3C outside, I estimate.

3.3kW for the small room.
5.5kW for the big room.

This is allowing 3 air changes rather than 1.5 to allow for draughts.
Also, I strongly suspect that wattle and daub will provide better than 1.5
uValue.

If, for example, you managed to fix the draughts and have a normal level
of
ventilation and the uValue turned out to be 0.8, you would get

2.1kW for the small room.
3.2kW for the big room.

Blimey is that all, I thought it would be a lot more than that.

Thanks

D

wattle and daub is very similar to (thicker) plasterboard: Key is the
air gap/cavity, which should be filled with insulation.

Any clue as to a u-Value, though? I presume uninsulated.

Christian.

Christian McArdle wrote:

wattle and daub is very similar to (thicker) plasterboard: Key is the
air gap/cavity, which should be filled with insulation.


Any clue as to a u-Value, though? I presume uninsulated.

err- work it out yourself from plasterboard, tinber and air gap values... :D

Having lived in wattle and daub, its better than single brick, a bit
better than double brick, but not as good as cavity insulated double
brick...

The killer is draughts.

Christian.