Thermal Stove v Unvented Cylinder
Discussion
We've just extended our home and are now considering what to do in terms of heating and domestic hot water. We've had three plumbers out so far, all giving different answers.
The question is, should we have an unvented cylinder or a thermal store?
System will have to cater for the following:
5 bed house
Grant Vortex Eco 21-26kw Oil fuelled condensing boiler
Multi Fuel Stove (if we decide Thermal Store then this will be a boiler stove - 20kw to water - we get free logs)
12 large rads
70m2 wet UFH
1 bathroom
2 en-suites
We currently have an additional 2 multi fuel burning stoves + 1 open fire. All regularly lit during the winter months.
Unvented Cylinder (210 litre advised?)
Pro's:
"Only" £500-£700 to purchase (looking at OSO cylinders).
Mains pressure hot water.
Con's:
Won't be able to connect Multi fuel boiler stove to the system.
Requires an annual service.
Requires sealed system" conversion kit for the boiler.
Thermal Store (400 litre capacity advised?)
Pro's:
Can connect Multi fuel boiler stove.
Doesn't require an annual service.
Mains pressure hot water.
Ease of connecting radiators/UFH.
Not sure if I'll need the "sealed system" conversion kit for the boiler?
Will I need fewer pumps/components for UFH?
Con's:
Cost - £1500-£3000. Unsure how to spec it with all the different options.
Help.
p.s. Gas is currently a no go.
The question is, should we have an unvented cylinder or a thermal store?
System will have to cater for the following:
5 bed house
Grant Vortex Eco 21-26kw Oil fuelled condensing boiler
Multi Fuel Stove (if we decide Thermal Store then this will be a boiler stove - 20kw to water - we get free logs)
12 large rads
70m2 wet UFH
1 bathroom
2 en-suites
We currently have an additional 2 multi fuel burning stoves + 1 open fire. All regularly lit during the winter months.
Unvented Cylinder (210 litre advised?)
Pro's:
"Only" £500-£700 to purchase (looking at OSO cylinders).
Mains pressure hot water.
Con's:
Won't be able to connect Multi fuel boiler stove to the system.
Requires an annual service.
Requires sealed system" conversion kit for the boiler.
Thermal Store (400 litre capacity advised?)
Pro's:
Can connect Multi fuel boiler stove.
Doesn't require an annual service.
Mains pressure hot water.
Ease of connecting radiators/UFH.
Not sure if I'll need the "sealed system" conversion kit for the boiler?
Will I need fewer pumps/components for UFH?
Con's:
Cost - £1500-£3000. Unsure how to spec it with all the different options.
Help.
p.s. Gas is currently a no go.
Thanks for the replies!
Will have a look if we have a 22mm incoming main or not.
Our Extension will be to building regs, so is well insulated. The original part of the house (1700's) has 500mm thick solid stone walls, smallish windows and lots of insulation in the loft. To be fair when we moved in, we expected it to be a cold house, we were surprised to find out it actually isn't.
Solar panels - Not really too keen on the idea, as I think they would ruin what is a "Chocolate Box Cottage". We are Listed too and our front elevation is South facing. If I could hide them, it would be a consideration.
What worries me about a 400 litre thermal store is the weight of the thing, sat on my first floor joists. I can't imagine it being that light and with us wanting to install a stove, am I correct in saying it needs to be on the first floor for the gravity feed?
Will have a look if we have a 22mm incoming main or not.
Our Extension will be to building regs, so is well insulated. The original part of the house (1700's) has 500mm thick solid stone walls, smallish windows and lots of insulation in the loft. To be fair when we moved in, we expected it to be a cold house, we were surprised to find out it actually isn't.
Solar panels - Not really too keen on the idea, as I think they would ruin what is a "Chocolate Box Cottage". We are Listed too and our front elevation is South facing. If I could hide them, it would be a consideration.
What worries me about a 400 litre thermal store is the weight of the thing, sat on my first floor joists. I can't imagine it being that light and with us wanting to install a stove, am I correct in saying it needs to be on the first floor for the gravity feed?
So it appears that we have 15mm incoming mains. Pressure is 3 bar and flow rate is about 13+ litres/min. Apparently anything above 8.5 litres/min is good (according to Severn Trent water).
I've got a plumber coming out to us within the week, to confirm the above and discuss what will suit us best.
In the meantime, I've been offered a 400L Thermal Store with:
Pump assembly for the oil boiler
Pump assembly for the radiators
Hot water set
Under floor heating pack
Connections for the solid fuel appliance
Immersion heater,
2 temp dials,
safety overheat thermostat,
boiler thermostat.
I assume a header/expansion tank will be required, so that will be an extra cost.
The only thing putting me off a thermal store is the weight. There's going to be half a tonne sat on the joists. Ideally I'd keep it on the ground floor, but don't think this is viable.
Another thing I will look into now is sealed system compatible stoves; I didn't realise they made them, so thanks for pointing that out.
I will keep this thread updated in terms of any other info I find and what ends up happening.
I've got a plumber coming out to us within the week, to confirm the above and discuss what will suit us best.
In the meantime, I've been offered a 400L Thermal Store with:
Pump assembly for the oil boiler
Pump assembly for the radiators
Hot water set
Under floor heating pack
Connections for the solid fuel appliance
Immersion heater,
2 temp dials,
safety overheat thermostat,
boiler thermostat.
I assume a header/expansion tank will be required, so that will be an extra cost.
The only thing putting me off a thermal store is the weight. There's going to be half a tonne sat on the joists. Ideally I'd keep it on the ground floor, but don't think this is viable.
Another thing I will look into now is sealed system compatible stoves; I didn't realise they made them, so thanks for pointing that out.
I will keep this thread updated in terms of any other info I find and what ends up happening.
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