Annex heating choices

[whiskeyfrank]

Hi

Another question while im here! I am converting an outbuilding to a granny flat for an elderly relative. Its at the bottom of my garden and not connected to the house.

It will have 1 bedroom, one living / dining, kitchen area, shower room and oak orangery. approx 800sqft

Underfloor heating is planned and we have no mains gas. I wasn't planning on a hot water storage.

Can anyone recommend a boiler for this system?

 

[andytw]

Whilst I wish your elderly relative as long and healthy life as is possible, do consider that in the future you may be renting the annex out. We did the same 30 years ago. We installed LPG heating so that the relative could have a gas fire. The relative is no longer with us, so we now rent out the annex. Managing the gas is not easy as it comes from a bulk tank which is shared with ourselves in our house. We have had to install a meter for the annex and bill the tenant directly. It is not cheap and it is not straightforward.
Personally I would be looking at smart electric radiators which are instructed to turn on and off at set times by a central programmer. The signalling is done down the mains cable itself.
I don't think underfloor heating is ideal for a rented property, but that's my opinion and it is not yet, and maybe never will be, a rented property.
Obviously you know your circumstances but just giving my 10p worth

andytw

 

[polesapart]

You've planned underfloor heating: what heat requirement did you or your installer calculate?

 

[whiskeyfrank]

I dont know the heat reqs its with the QS at the moment.

The annex will never be rented it was part of the agreement for planning, its 100m from the house and has its own car parking etc and as we are in an area of ONB they wanted some covenants.

However, I also have a teenage son and he has his eye on it already for when he's a bit older - free house he will never leave!

 

[muggles]

If you want to go the LPG Combi route, I'd say either the Intergas Combi Compact HRE 24/18 or the Vokera Unica 28i. It's a small area to heat so you need something with a very low minimum output to make sure it doesn't cycle too much. Intergas are my boiler of choice but the Vokera has slightly better hot water output and a lower minimum output (4.6kw (EDIT...3.95kW) against IG's 5.6kW).

You won't be able to heat the orangery off the boiler as it won't pass building regs, unless the orangery is being constructed to meet current energy efficiency regulations for domestic dwellings (Part L compliance), so you'll need a separate heat source for that

 

[andytw]

Off topic I know but......Understood re planning and renting...same conditions were imposed here but really saw no option to renting when the annex was assessed as being a separate dwelling and given it's own Band A council tax bill ! One to watch for.

 

[vulcancontinental]

3.96KW on the 28i on LPG unless there's been a re-write

 

[muggles]

3.95KW on the 28i on LPG unless there's been a re-write

So it is...I was reading it on my phone! That's my excuse and I'm sticking to it

 

[whiskeyfrank]

If you want to go the LPG Combi route, I'd say either the Intergas Combi Compact HRE 24/18 or the Vokera Unica 28i. It's a small area to heat so you need something with a very low minimum output to make sure it doesn't cycle too much. Intergas are my boiler of choice but the Vokera has slightly better hot water output and a lower minimum output (4.6kw (EDIT...3.95kW) against IG's 5.6kW).

You won't be able to heat the orangery off the boiler as it won't pass building regs, unless the orangery is being constructed to meet current energy efficiency regulations for domestic dwellings (Part L compliance), so you'll need a separate heat source for that

Do you think the LPG route would be better than oil - running costs wise. Ive looked and the boilers are much cheaper than oil?

The orangery is separated by bifold doors to keep within the regs.

 

[whiskeyfrank]

Off topic I know but......Understood re planning and renting...same conditions were imposed here but really saw no option to renting when the annex was assessed as being a separate dwelling and given it's own Band A council tax bill ! One to watch for.

Thanks very much for the heads up. The restriction was from our neighbours as they are concerned we would sell it as a separate house, so its been quite binding. We are also doing this as there is such high demand for housing with a granny annexe as we know from our own experience, as my wife relative is disabled we do get a council tax reduction. For the future who knows, but she no doubt outlive me!!

 

[muggles]

If you want to go the LPG Combi route, I'd say either the Intergas Combi Compact HRE 24/18 or the Vokera Unica 28i. It's a small area to heat so you need something with a very low minimum output to make sure it doesn't cycle too much. Intergas are my boiler of choice but the Vokera has slightly better hot water output and a lower minimum output (4.6kw (EDIT...3.95kW) against IG's 5.6kW).

You won't be able to heat the orangery off the boiler as it won't pass building regs, unless the orangery is being constructed to meet current energy efficiency regulations for domestic dwellings (Part L compliance), so you'll need a separate heat source for that

Do you think the LPG route would be better than oil - running costs wise. Ive looked and the boilers are much cheaper than oil?

The orangery is separated by bifold doors to keep within the regs.

For a small area like this, yes, LPG will be far more suitable.

You can have all the doors you like - you're still not allowed to heat it off the boiler

 

[Agile]

Silly but we still don't know how you heat your main house!

Surely you will want to use the same fuel as that so it can be bought in bulk and delivered to just one tank. Also significantly reduces the capital cost.

100m of supply to the annex should not be any problem.

Tony

 

[OwainDIYer]

The orangery is separated by bifold doors to keep within the regs.

You can have all the doors you like - you're still not allowed to heat it off the boiler

The heat source doesn't matter - although radiant heat might be better - but it must be separately controllable eg on its own zone with separate timer/stat to the main house.

100 metres of gas pipe to the annexe might not be a problem but water supply may be, if it's intended to use mains pressure / no storage hot water.

 

[muggles]

The orangery is separated by bifold doors to keep within the regs.

You can have all the doors you like - you're still not allowed to heat it off the boiler

The heat source doesn't matter - although radiant heat might be better - but it must be separately controllable eg on its own zone with separate timer/stat to the main house.

You're five years out of date...the separate zone rule went out of the window in 2010. It must now be a separate heat source (or at least that's my interpretation of the wording "Regulation 21...exempts some conservatory and porch extensions from the energy efficiency requirements...where the heating system of the dwelling is not extended into the conservatory or porch"). Having a separate zone for the conservatory, attached to the heating system for the dwelling, does not in my opinion constitute not extending the heating system into the conservatory

 

[muggles]

Silly but we still don't know how you heat your main house!

Surely you will want to use the same fuel as that so it can be bought in bulk and delivered to just one tank. Also significantly reduces the capital cost.

100m of supply to the annex should not be any problem.

Tony

It's not mains gas, so I would assume it's oil as the OP asked about oil further down the post. Do you really think a non-modulating 24kW oil combi would be cheaper to buy and run than an LPG Unica running off bottles in a well-insulated 1-bed 3-room flat? Ignoring the orangery, it's going use, what, 6kW max?