Can an unvented indirect cylinder be used just on electric?

[rikpal]

I'm looking at getting an unvented cylinder fitted as i'm redoing the bathroom, at the moment its a direct system, but next year I'm looking to swap to an airsource heat pump.
Can a high efficiency indurect cylinder be used as a direct one i.e add 2 elements,. Just so i can th en plumb in the ashp.?

 

[Brambles]

Yes you can, but your electricity bills will be in the region of £350/month if you are heating on two 3kw immersion heaters.

When you convert to ASHP, the UV tank needs to have the appropriate coil(s) - a traditional UV cylinder with a coil for gas or oil will not deliver a satisfactory performance if connected directly to normal temperature ASHP - they will work ( with tweaking) with a high temperature ASHP

 

[Roy_66]

Hi Rikpal,

Another silly question. Is your intended ASHP just going to be on the water? Beware if you also put it on the heating you may need bigger rads (similar reason to the bigger tank coil above).

Also be careful, in winter it may not give you enough heat and you will need to top up which may need expensive immersion? (I'd get expert advice first, either independent specialist plumber, or RICs surveyor who specialise in these new systems. Some of the people selling this stuff don't yet understand what they are doing. . . ). Think about it, when it's freezing outside an ASHP will struggle.

I think for the country as a whole the future is gas (homes and cars) by converting in about 10 years time to hydrogen. Have a listen to Roger's rant:


Cheers,

Roy (amateur all trades)

 

[Brambles]

Roy makes some good points. Be aware that the current RHI scheme closes to new applications in March 2022 ( system has to be fully up and running by then) that gives you the circa 10p unit subsidy from the predicated energy consumption shown in your EPC. That needs to be prepared properly the first time - not a £50 drive by job - once an EPC is in the system with the wrong numbers it is very difficult to get it replaced.

To maximise RHI payment it is better to use solar thermal for hot water and ASHP for heating.

Whilst that seems a long time off - it is a very busy market at the moment - well it is in Oxfordshire.

Hydrogen? Time will tell - it is not an issue to burn in traditional boilers - Towns gas was hydrogen - it was the CO and CO2 in it that was the killer. Low density gas, high gross calorific value - but you need circa twice as much in volume terms to get the same gross output as Natural Gas

 

[rikpal]

Hi Rikpal,

Another silly question. Is your intended ASHP just going to be on the water? Beware if you also put it on the heating you may need bigger rads (similar reason to the bigger tank coil above).

Also be careful, in winter it may not give you enough heat and you will need to top up which may need expensive immersion? (I'd get expert advice first, either independent specialist plumber, or RICs surveyor who specialise in these new systems. Some of the people selling this stuff don't yet understand what they are doing. . . ). Think about it, when it's freezing outside an ASHP will struggle.

I think for the country as a whole the future is gas (homes and cars) by converting in about 10 years time to hydrogen. Have a listen to Roger's rant:


Cheers,

Roy (amateur all trades)

Cheers for the reply, unfortunately gas isn't an option, currently on economy seven storage heating, so i would still use economy 7 tarrif until ashp installed.
I' ve had to delay it as once i did the proper rhi calculations I get around £7000. The system is coming in at between £10 k and £12k. So i need to find the extra. ( Initialy i was quoted as being able to get maximum rhi by a company, they had put in 20,000kw/h energy usage for a 3 bed semi ) .

 

[rikpal]

Roy makes some good points. Be aware that the current RHI scheme closes to new applications in March 2022 ( system has to be fully up and running by then) that gives you the circa 10p unit subsidy from the predicated energy consumption shown in your EPC. That needs to be prepared properly the first time - not a £50 drive by job - once an EPC is in the system with the wrong numbers it is very difficult to get it replaced.

To maximise RHI payment it is better to use solar thermal for hot water and ASHP for heating.

Whilst that seems a long time off - it is a very busy market at the moment - well it is in Oxfordshire.

Hydrogen? Time will tell - it is not an issue to burn in traditional boilers - Towns gas was hydrogen - it was the CO and CO2 in it that was the killer. Low density gas, high gross calorific value - but you need circa twice as much in volume terms to get the same gross output as Natural Gas

Hydrogen is certainly the way it looks like going, certainly in cities, I work for a housing association and Ashp wouldn't work in over 1/2 the houses, partly down to costs of getting buildings upto standard, but also getting tenents to use an ashp properly. Plus the cost of fixing when they get trashed.