Boiler

[Jason L]

I had decided on a small gas combi boiler, for my house it will be about 110sq.m. with 3 bedrooms, 2 bathrooms and a cloakroom.

 

I quite like the idea of an electric combi boiler, as its cleaner,  quiet in use and doesn't require a flue, which saves a big hole through the wall !  and the specs suggest that they are very efficient (100%)  another bonus if i had one, i wouldn't have a mains gas connection. 

 

Have any of you any experience with an electric combi boiler, if so what's your opinion ?

Ta.

[nod]

10 minutes ago, Jason L said:

I had decided on a small gas combi boiler, for my house it will be about 110sq.m. with 3 bedrooms, 2 bathrooms and a cloakroom.

 

I quite like the idea of an electric combi boiler, as its cleaner,  quiet in use and doesn't require a flue, which saves a big hole through the wall !  and the specs suggest that they are very efficient (100%)  another bonus if i had one, i wouldn't have a mains gas connection. 

 

Have any of you any experience with an electric combi boiler, if so what's your opinion ?

Ta.

Just googled the running costs Almost 5 times as much as gas mains 

[ProDave]

Electric boilers only make sense if you can run them on a cheap off peak tariff.  Economy 10 makes quite a bit of sense as you can put most of the heating load onto the cheap rate.

 

But a MUCH better idea for all electric heating is a heat pump. 

 

If gas is available it will be the cheapest option no doubt about that.

[Jason L]

4 minutes ago, nod said:

Just googled the running costs Almost 5 times as much as gas mains 

?  ohh i wouldn't be keen on that  cheers

[Jason L]

2 minutes ago, ProDave said:

Electric boilers only make sense if you can run them on a cheap off peak tariff.  Economy 10 makes quite a bit of sense as you can put most of the heating load onto the cheap rate.

 

But a MUCH better idea for all electric heating is a heat pump. 

 

If gas is available it will be the cheapest option no doubt about that.

ok cheers 

[PeterW]

They are expensive to run, and horrendous at anything like a decent flow rate unless you get a 3 phase one. Avoid like the plague 

[Jason L]

9 minutes ago, PeterW said:

They are expensive to run, and horrendous at anything like a decent flow rate unless you get a 3 phase one. Avoid like the plague 

A gas boiler it is then !   cheers

[Temp]

@Jason L

 

+1 to mains gas.

 

Electricity costs at least double mains gas per kWh. So it only makes sense to use electricity if you use it to power a heat pump. Under the right conditions Heat pumps can be  >200% efficient. However the efficiency can vary from 100% to 350% so care is needed when choosing one. 

 

 

[Jason L]

4 minutes ago, Temp said:

@Jason L

 

+1 to mains gas.

 

Electricity costs at least double mains gas per kWh. So it only makes sense to use electricity if you use it to power a heat pump. Under the right conditions Heat pumps can be  >200% efficient. However the efficiency can vary from 100% to 350% so care is needed when choosing one. 

 

 

ok thank  you.

[Jason L]

I now have my design SAP rating,  from that are you clever people able to work out what size Gas combi boiler i would need and its weekly usage ??

[Temp]

If its a very vell insulated house the size of boiler maybe dictated by the DHW flow rate. Eg if you want to run two showers at once it may need to be a 20KW boiler. So when both are running each would have a flow rate similar to a 10kW electric shower.

[Jason L]

11 minutes ago, Temp said:

If its a very vell insulated house the size of boiler maybe dictated by the DHW flow rate. Eg if you want to run two showers at once it may need to be a 20KW boiler. So when both are running each would have a flow rate similar to a 10kW electric shower.

Ahh yes i remember the SAP guy saying something along those lines,  it will be well insulated and super air tight.

cheers

[Jason L]

I'm just looking at some Gas combi boilers and some are saying not compatible with solar panels,  what does that mean?  ie what does the solar panel have to do with the gas boiler ?

 

[TonyT]

What kind of solar panels are you talking about?

 

solar Thermal or PV

[Jason L]

1 minute ago, TonyT said:

What kind of solar panels are you talking about?

 

solar Thermal or PV

im having PV panels 

[TonyT]

PV panels generate electricity so have no adverse impact with a combi boiler. 
 

that’s exactly what I have , no issues in the past 10 years

[Jason L]

Just now, TonyT said:

PV panels generate electricity so have no adverse impact with a combi boiler. 
 

that’s exactly what I have , no issues in the past 10 years

ah that's good, as it was confusing me,

cheers

[TonyT]

Probably because some people may want to use a system boiler and hot water cylinder with an immersion and use a diverter to maximise solar power to power the immersion...

 

I don’t have room for a cylinder so that why I have a combi. 

[A_L]

4 minutes ago, Jason L said:

some are saying not compatible with solar panels,  what does that mean? 

 

Usually that there are plastic parts in the input to the boiler which cannot take water above 30°C from solar thermal heated water stored in a buffer before the boiler

 

If you insulate opaque building elements to 0.11W/m².K, windows to 0.8W/m².K and infiltration to 0.6ach@50Pa and fit MVHR, average CH heating requirements can be around 800kWh/yr and at this level the low capital cost of a Willis type heater (immersion in a pipe) can offer a cost effective alternative system.

[Jason L]

40 minutes ago, A_L said:

 

Usually that there are plastic parts in the input to the boiler which cannot take water above 30°C from solar thermal heated water stored in a buffer before the boiler

 

If you insulate opaque building elements to 0.11W/m².K, windows to 0.8W/m².K and infiltration to 0.6ach@50Pa and fit MVHR, average CH heating requirements can be around 800kWh/yr and at this level the low capital cost of a Willis type heater (immersion in a pipe) can offer a cost effective alternative system.

Cheers that makes sense.   What does 800kwh/ year equal in £ using a gas boiler? As I tried to work it out and got to £30.40  that doesn’t sound,  right it will be nice tho  ? 

[A_L]

@Jason L , it is correct ?, it is roughly the basic elements of a Passivhaus build in our milder climate. N.B. it does not include about 2500kWh/yr for DHW!

[Jason L]

12 minutes ago, A_L said:

@Jason L , it is correct ?, it is roughly the basic elements of a Passivhaus build in our milder climate. N.B. it does not include about 2500kWh/yr for DHW!

?. Well my house  isn’t quite that good a spec but, it’s not very big, so that’s encouraging thank you ?.