I'm currently pondering what the options might be when the time comes to
replace our elderly heating system. Since we're on oil and wood, it isn't
immediately obvious that a like-for-like replacement is the way forward.

Are there any tools around to help select what might be plausible options?

I came across:
https://homerenewableselector.est.org.uk/
which is quite good at doing an overview of various energy sources and their
likely yield and RoI. However it only works for Scotland - seems like they
didn't get their funding renewed for E&W and NI. That aside, it looks
useful if you put in a Scottish postcode and expect to tweak the numbers for
latitude and available grants.

However, what I'm more interested in is a bit more detail. For example, a
particular solution will need a 1000l thermal store that will cost £x, a
37mm pump £y, a controller £z, and if straightforward it'll take three days
to fit. Is there anything out there that will spec out what a system might
need, especially more complicated ones (solar hot water, ASHP, back boiler
on the stove, ...)? It doesn't matter if things aren't costed, but at least
a vague shopping list would be handy to price things up later.

Of course I could go to an installer for this. But I'd like to know a
little more before going and being sold their favourite one-size-fits-all
solution.

Are there design tools out there that the installers use, or do they just do
it by hand?

Thanks
Theo

On Sunday, 5 July 2020 22:53:43 UTC+1, Theo wrote:
I'm currently pondering what the options might be when the time comes to
replace our elderly heating system. Since we're on oil and wood, it isn't
immediately obvious that a like-for-like replacement is the way forward.

I think the first thing is to establish what's wrong (or less than optimal) with the current system. Is it inconvenient, expensive to run, inefficient, etc.

Wood and oil have the potential of being off-grid (with an inverter for control and pump). Bulk tank LPG is another stored fuel. You also have the option of buying fuel when cheapest and storing it, which evens out seasonal fluctuations. The drawback is possibly large payments in advance rather than a nice monthly bill.

If you need new radiators and a hot water cylinder, good rads and cylinder will work with almost all boiler based systems, but check what tappings/coils are required on the HW cylinder. On the other hand, if your radiators and pipes are knackered then that may slightly influence towards a non-hydronic heating system, whether heat pump or electric thermal storage, which doesn't incur the radiator replacement cost.

Gas boilers are being banned for new builds fairly soon, but they'll probably still be preferred by most buyers for a while. If mains gas is or may be available, at the moment that's the default option unless there are compelling reason not to (eg you like chopping lots of free wood). For those of us getting a little longer in tooth, not having to chop wood might be welcome.

And there are trade-offs of initial cost, running cost, longevity, convenience, and eco-niceness.

Owain

wrote:
On Sunday, 5 July 2020 22:53:43 UTC+1, Theo wrote:
I'm currently pondering what the options might be when the time comes to
replace our elderly heating system. Since we're on oil and wood, it isn't
immediately obvious that a like-for-like replacement is the way forward.

I think the first thing is to establish what's wrong (or less than
optimal) with the current system. Is it inconvenient, expensive to run,
inefficient, etc.

The boiler is 20 years old, and servicing isn't that cheap. In a few months
there's already been one breakdown. I suspect it'll get steeper from here
on. It heats the hot water any time the heating is on. The oil tank is
annoyingly placed. The boiler rattles a lot. The electric shower is barely
usable and we'd like to replace with a stored HW system. Haven't seen it
through a winter yet, so don't know how it is to live with the boiler on
full time, how much heat we can get from the woodburner and how much the
boiler drinks oil. No mains gas.

All little things, fixable individually, but makes me wonder what more
drastic changes might look like.

And there are trade-offs of initial cost, running cost, longevity,
convenience, and eco-niceness.

Which was the reason for my question - I'd like to explore those tradeoffs
in more detail. Beyond the 'system of type X will cost £yy,000' level of
the EST tools.

THeo

On 06/07/2020 10:55, Theo wrote:
The boiler is 20 years old, and servicing isn't that cheap. In a few months
there's already been one breakdown. I suspect it'll get steeper from here
on. It heats the hot water any time the heating is on. The oil tank is
annoyingly placed. The boiler rattles a lot. The electric shower is barely
usable and we'd like to replace with a stored HW system. Haven't seen it
through a winter yet, so don't know how it is to live with the boiler on
full time, how much heat we can get from the woodburner and how much the
boiler drinks oil. No mains gas.


Well I have a similar setup and the good news is that all the parts are,
so to speak independent. There are no real 'critical paths'

So lets talk about hot water. Electric showers are, by and large, pants.
So let's assume mains pressure stored hot water is on the menu. The good
news is that it can go anywhere - doesn't need to be 'up high' and it
can run off the same primary circuit as the old tank did. My experience
of a large house sparsely occupied is that of all the things that cost
money, heating water is the least of my worries. Perhaps £160 a year in
a £2000 oil bill? So how much of that £160 would be saved by having it
separately timed from the heating? not a lot, but then again, the cost
of inserting a motorised valve in the circuit and wiring its contacts in
parallel with the central heating, and driving the motor off a two way
timer, is not great either. Bear in mind also that a mains pressure tank
without a water softener in a hard water area is an expensive thing to
replace when it gets scaled up...



Also, consider: I have UFH and I never switch it off. The thermostat in
the living room does that for me. It hasn't run for two months, because
the room never drops below 19°C. So timing as such - particularly in a
house with a LONG thermal time constant - ain't half so important as
room stats everywhere on radiators and a good central thermostat to shut
the thing down centrally.Timers belong to the days when houses had no
insulation, lost heat in minutes and got warm in minutes too, and people
were out at work all day.I'd far rather have stats on every room than a
timer on a properly insulated house.

So pressurised tank and its plumbing is completely orthogonal to any
boiler change, timer change or anything. A friend I advised to get one,
had it added to his old boiler, which finally gave up the ghost ten
years later, and was replaced completely independently.

Likewise, moving the oil tank is completely orthogonal as well. You can
likewise do that at any time. Bear in mind the current regulations on
placement and bunding though.

Is an oil boiler worth replacing ? Mine is 20 years old and filing
gracefully - the pressure meter don't work, its got a slight gland leak
from the high pressure part, but it fires up and runs if I add water
every few months, £5k to replace in all probability, to save what? maybe
£500 a year? Will I be here in ten years? Will I be alive at all in ten
years?


All little things, fixable individually, but makes me wonder what more
drastic changes might look like.

*shrug* just more expensive. If 'getting a man in' the issue is perhaps
as to whether a large chunk of work might be more attractive than
smaller chunks. They will try and rip you a bit whatever..


And there are trade-offs of initial cost, running cost, longevity,
convenience, and eco-niceness.

Bollox to eco niceness. Its all a scam anyway.
Cost-benefit analysis and let your head rule your heart.

Which was the reason for my question - I'd like to explore those tradeoffs
in more detail. Beyond the 'system of type X will cost £yy,000' level of
the EST tools.

All depends on the actual plumbing changes. A boiler should be less than
two days to install into existing pipework. mains pressure less than
that and an oil tank about a day, unless you need to build support piers.

Timers and electrical shaggery are subject to the same issues as
plumbing - where to run cables and pipes and how much it takes to do a
neat job.

Very much better to DIY if you can



--
Climate Change: Socialism wearing a lab coat.