Opinions on changing non boiler stove for boiler

ifeelstupid

Hi
Just looking for opinions as to whether I should do this or not.
I had a Mulberry non boiler inset stove installed about 2 yrs ago. Since day 1 I have been a bit disappointed with it. I was put off putting in a boiler stove at the time because of the amount of work involvedto get pipes to hot press etc. It also needed a bit of extra work at the boiler house.
I have been playing around with the idea of swooping it out for a boiler stove. Quote for everything (including stove and all materials) is around €2500. Stove I have been quoted for is Henley Achill 17kw. House is a 4-bed semi around 10 years old. Job includes work I didn't do the last time - new chimney flue and outside vent in sitting room and obviously the pipe work etc to hot press. quote also covers any building works and boxing in pipes. Tank does not need to be replaced.
Im only actually home about 3/4 evenings a week but my mum stays with me for a couple of weeks at a time every now and then and she likes her heat!!
Any opinions welcome - I'm just not sure if the benefits outweigh the cost and disruption (even though plumber has told me it will be 2 days max!)
Thanks

my3cents

First question I'd ask anyone doing the work is how is the stove going to heat the HWC and what happens if the electric goes off?

The system should be plumbed so that even if the electric goes off there is somewhere, normally the HWC, that can keep absorbing the heat to help prevent turning the stoves boiler into a bomb. I know of a good few installations that because they are added to an existing system don't have this basic safety feature.

You need to check its being done right before you do it at all.

TPM

Why doesnt the cylinder need to be replaced?
where is the cylinder in relation to the stove, distance and height?
what is heating your rads at the moment, is the system pressurised?

typically when you replace a non boiler stove with a boiler stove you will burn 3 times the amount of fuel to get the same heat to the room

ifeelstupid

Plumber said the cylinder doesn't need replacing. Even though it was new, I changed out the cylinder when I moved in because the one that was already here was too small for family use.
House is a typical semi, cylinder is in hot press on first floor landing, not directly above fireplace so it will be necessary to lift floorboard in one bedroom to get pipework to it.
Heating rads currently using the oil boiler, system is pressurised and there are pumps for ground floor and first floor in the boiler house. I only turn the heat for about an hour morning and evening. Mind you it hasn't been very cold yet.
Living room is not huge so I'm not too concerned that the stove will not put as much heat out to the room.
To be honest I think I like the idea of the boiler stove more than I actually need one - although there is one room that would probably benefit from it. It's a ground floor bedroom that seems to be much colder than the rest of the house. Maybe because it has external wall on 2 sides?

TPM

ifeelstupid wrote: »

Plumber said the cylinder doesn't need replacing. Even though it was new, I changed out the cylinder when I moved in because the one that was already here was too small for family use.

The cylinder must have 2 coils in order to connect the stove to it.

ifeelstupid wrote: »

House is a typical semi, cylinder is in hot press on first floor landing, not directly above fireplace so it will be necessary to lift floorboard in one bedroom to get pipework to it.

the pipe from the boiler must rise continuously with no valves to the cylinder, this can be difficult to maintain when travelling under floors.

ifeelstupid wrote: »

Heating rads currently using the oil boiler, system is pressurised and there are pumps for ground floor and first floor in the boiler house.

solid fuel must be on an open vent system, if your existing system was originally designed and installed as a pressurised system there is a fair chance it wont work as well converted to open vent.
the first floor rad pipework should be altered to allow thermosyphon in the event of power failure.

also for reference solid fuel boilers cannot be connected to pressurised hot water cylinders.

ifeelstupid wrote: »

Living room is not huge so I'm not too concerned that the stove will not put as much heat out to the room.

I generally find people are surprised at how much fuel you need to put into a boiler stove to get the heat they want. with the room the stove is in ranging from warm to too hot while trying to heat the rest of the house.

ifeelstupid wrote: »

there is one room that would probably benefit from it. It's a ground floor bedroom that seems to be much colder than the rest of the house. Maybe because it has external wall on 2 sides?

If the room isnt heating well from the oil the chances are it will be worse with the stove taking into account the change to open vent system and the lower heat output from the stove v the oil.

if the rad is getting hot and the room is cold you could fit a bigger rad.
if the rad isnt heating you could either have a balancing issue or a plumbing problem.

ifeelstupid wrote: »

To be honest I think I like the idea of the boiler stove more than I actually need one

the idea is always appealing but the reality seldom matches the idea.
from the information in this thread and my past experiences i would recommend against changing to a boiler stove.
unless you have a source of cheap fuel the cost of heat per kw, is seldom cheaper than oil, the heat out put from the stove (room and rads) tends to be below expectations, the existing oil system could possible preform worse after the work is completed.

of course all this is my opinion based on my experience/knowledge and my interpretation of your existing and proposed system. all of which is open to contradiction/question.

ifeelstupid

Thank you TPM for such a comprehensive reply. I have spent a bit (or maybe a lot) of time over the weekend weighing it up and I think for now it's a project I will put on hold. Aside from everything else it seem the cost/benefit ratio just doesn't add up. Thanks again for your input.

TPM

ifeelstupid wrote: »

Aside from everything else it seem the cost/benefit ratio just doesn't add up.

and that is the main factor in most projects

ifeelstupid

TPM wrote: »

and that is the main factor in most projects

You're far too sensible:D

OwenM

The cost/benefit ratio is the main factor, but long term thinking is needed too. Oil is approx €45 a barrel today, two years ago it was nearly three times that. What happens to your annual heating bill when oil doubles in price?

I had an open system, then a plumber told me he would have to pressurise it to do a certain job, I reluctantly agreed and then when I came to fit my boiler stove the system was restored back to an open one.

What are the obstacles going from a pressurised system to an open one, apart from height for expansion?

BTW I have the same stove, Henly Achill 17Kw heating 10 rads and spend €900 p.a. on wood in a 1960's 3 bed semi. I might burn €100 worth of kerosene in my oil boiler each year as well.

TPM

OwenM wrote: »

Oil is approx €45 a barrel today, two years ago it was nearly three times that. What happens to your annual heating bill when oil doubles in price?

very valid point and worth taking into consideration. other fuels tend to change price as well but not as aggressively as oil. and oil could also stay the same or drop in price.

OwenM wrote: »

BTW I have the same stove, Henly Achill 17Kw heating 10 rads and spend €900 p.a. on wood in a 1960's 3 bed semi. I might burn €100 worth of kerosene in my oil boiler each year as well.

how long would have the same value of kerosene lasted?
how much per bag, tonne was the wood you bought

I have a 30kw boru stove which heated the house for a full winter for about e50
(for petrol to cut up the beech tree that blew down the year before )

my point being the individual heating cost needs to be comparative to other sources and the cost of the same fuel to each person at the time.

OwenM wrote: »

I had an open system, then a plumber told me he would have to pressurise it to do a certain job, I reluctantly agreed and then when I came to fit my boiler stove the system was restored back to an open one.

What are the obstacles going from a pressurised system to an open one, apart from height for expansion?.

your system was originally designed and installed open vent, a system that is installed pressurised may not have paid the same attention to the restriction in the pipe work as on the closed system the pump could be turned up to push the heat around with out worrying about pumping into the header tank.

OwenM

TPM wrote: »

how long would have the same value of kerosene lasted?
how much per bag, tonne was the wood you bought

Winter of 14/15 my kerosene bill was about €1300-1400 (before i got the stove) and oil about the same price it is today.

Last winter I spent €900 on wood with oil at €30-35 so I was close to breakeven in base cost. i.e. I think the same value of kerosene would have cost me €1100 - 1200 but it's difficult to compare as we use the stove more then we would have the oil.

I buy wood by trailer load, typically three cubic metres of Ash/Beech/Oak at ~20% m/c (loose packed) would cost me €270 - €280. I also have a guy doing Larch at around 17% m/c for €60 m3. There is a fair bit of work getting that into my shed each year but the exercise is welcome, especially when I plan it in advance, my shed has been full since the end of May and I took deliverys when the guys selling it were coming to the end of their season and the weather was good.

TPM

nice breakdown thanks.

was that about 10 cubic meters of wood you burnt last year.

do you think it would be fair to say if you couldnt buy, handle and store wood in the volumes your are the cost of the running stove could be fairly close to the cost of the oil boiler?

just as you could work with larger volumes the savings could be greater

by the way I am not anti-stoves/solid fuel just that in my experience people often have unrealistic expectations of what stoves can do, underestimated running costs.

OwenM

Yeah about 10m3, and bulk buying is important but there are other factors. The cost is about equal with oil at $35, I think I'm about 20% better off using wood with todays prices

Low moisture content is very important in a few respects:

a) It is noticeably easier to carry 150 buckets of wood @20% v's 40% into my shed when I get a delivery
b) The heat output is much greater.
c) Creosote buildup is much slower.

Stoves aren't a magic bullet and people who haven't upgraded their insulation aren't going to fix a cold house or save money with one.

By far the biggest ripoff in the Irish home heating market today is electricity, followed by bulk LPG and bottled gas, i.e. rural houses with their own gas tank out the back. The standing costs of bulk LPG aren't included in the comparison below.

http://www.seai.ie/Publications/Statistics_Publications/Fuel_Cost_Comparison/Domestic-Fuel-Cost-Comparisons.pdf