What is the most cost efficient boiler for a large house?

jony_dols

Hi, I'm just writing this up for an elderly neighbor of mine, who is having difficulties keeping his old 4,500sq ft country house warm. Damp is an issue & the cost of fueling his oil burner is now astronomical.

What is his best option? (i.e coal, pellet or LGP). And, is there any specific makes like Defro or Greenman that are best? A self-feeding system would be preferable for him.

Thanks.

Irish Steve

Forget LPG, the cost per Kw.h delivered is even higher than oil.

There is a fundamental issue here that changing the boiler won't address as such, which is that something needs to be done to reduce the heat input into the house. If that's not done, then it's still going to be expensive to heat.

Coal or Pellets are not ideal for an elderly person, as there's carrying, and weight involved, unless an automatic feed wood pellet system is put in, but the impression I am getting of them from comments here would make me wonder about the long term reliability of that system.

The other aspect that needs to be addressed is the total cost of the changes, depending on the age of the neighbour, the cost of making changes to the system may be significantly in excess of the cost of continuing to run the present system, depending on your neighbour's long term plans. Finding a buyer for a large property may well be an issue at the moment, as the market for larger property is still very flat, and downsizing may not be an option for other reasons, but if the cost of upgrading is significant, the reduction from a change to cheaper fuel may mean that it's going to be a long time before that cost is recovered in lower operating costs.

This is going to need to be looked at very carefully.

Latro

I moved into my new house in September. It's new build before 2008 regs.Total area heated about 200sqm.
We have Defro solid fuel boiler with automatic feed + 1000l buffer tank. Coal peas is the primary fuel.
So far cost of heating + hot water for one winter month is about 120 euro. We top it up with 200kg of coal every 12 days.

It requires a little of maintenance though:
-loading fuel (in our case once every 12 days)
-taking out ashes (once a week)
-cleaning inside (once every 2 weeks)
-flue cleaning (once a year)

All in all I can say that I'm happy with the heating. Not maintenance free but relatively cheap.
It's set to be on from 4am to 11pm. The house maintains constant temperature of about 20 degrees throughout the day. It drops by 1-2 degrees in the night when the boiler goes into sustain mode for few hours.
When we moved in and started heating, 1st month cost me nothing since I had lots of timber from the building site. I gave up the idea of burning it after a few weeks because it takes a lot of hassle of topping up the timber and taking out ashes and I switched to coal automatic feed.
I can't imagine how some people use their back boiler stoves in their living rooms as main source of heating. Must be a mess bringing all that fuel in and ashes out on daily basis.

jony_dols

Thanks Steve & Latro, for their advise.

Our neighbor is pushing 70, but has had a recent health scare, leaving him not as nimble as he used to be. I've no problem helping him fill & maintain an automatic feed system, a few times a month.

Downsizing really isn't an option for him, but if the likes of a Defro duo can pay itself off in a few years & help prevent the house deteriorating due to damp, then it seems like a viable option.

If anyone has experience like Latro's with other automatic feed systems, I'd appreciate the feedback.

Thanks again.

Fox 1

Just new to boards I was wondering what size of boiler did you put in I was thinking of a dafro my self what model is it. Thanks

Latro

Fox 1 wrote: »

Just new to boards I was wondering what size of boiler did you put in I was thinking of a dafro my self what model is it. Thanks

There are many models. I got AKM Duo 19KW but from perspective of few months its way too big for the size of the house(200sqm). I'd get 14-15 KW model if I had to do it again. The less it sits in "sustain" mode the better.

jj58

grant spira wood pellet boiler, at 270 per bag.. 567 euros worth of pellets = 1000 litres of oil
+ the boiler is more efficent too betwwen 5 and 10% than most standard boilers

Fox 1

Sorry as you know I am only new to boards .what is they best way to get to talk to you as I maybe considering a coal boiler thanks again

eamonndo

Latro wrote: »

There are many models. I got AKM Duo 19KW but from perspective of few months its way too big for the size of the house(200sqm). I'd get 14-15 KW model if I had to do it again. The less it sits in "sustain" mode the better.

Just curious - why do you say it is better the less it sits in "sustain" mode?

ccsolar

jony_dols wrote: »

Hi, I'm just writing this up for an elderly neighbor of mine, who is having difficulties keeping his old 4,500sq ft country house warm. Damp is an issue & the cost of fueling his oil burner is now astronomical.

What is his best option? (i.e coal, pellet or LGP). And, is there any specific makes like Defro or Greenman that are best? A self-feeding system would be preferable for him.

Thanks.

Hi
There is no point firing heat into this house if damp is an issue then there is also a poor insulation issue
You need to get onto the health board or county council and find out about some grants for this gentleman first , then get a pre BER rating on the property which will high light the areas that can be improved before you carry out any work.
Cc

Latro

eamonndo wrote: »

Just curious - why do you say it is better the less it sits in "sustain" mode?

It goes into sustain mode when set temperature is reached. It uses very little amount of fuel then to maintain minimal fire. If you oversize the boiler it will sit in that mode most of the time.

zoom_cool

How is your Defro boiler going thinking of getting one

Latro wrote: »

There are many models. I got AKM Duo 19KW but from perspective of few months its way too big for the size of the house(200sqm). I'd get 14-15 KW model if I had to do it again. The less it sits in "sustain" mode the better.

Latro

It's definitely worth getting, especially if it is new build.
6 months of hot water and nearly constant heating cost me about E500.

Just make sure you are ready to put that little bit of your own work into it.
The cleaning is a little bit of dirty job.
Loading it and emptying is fairly easy going.

Don't get bigger boiler than 15KW no matter what they say to you in the shop.
Attaching buffer(about 1000L) if you have space is good too as it stabilizes nicely the whole system.

From perspective of time my dream heating system would be geothermal ground source with at least 1500L buffer run on night rate only.
But that would be very expensive to set up and expensive to fix in case of future failures.

Initially I wanted to go oil+back boiler route but when I thought of the mountain of fuel and ashes that has to be brought in and out of my open plan leaving room I decided to set up a proper "back boiler" in the garage in form of solid fuel boiler.

zoom_cool

Hi Latro

Thanks for the information how what type of fuel do you use is it coal and how much does the coal cost. I have a 1400sq feet buglow with 13 Rads so I would imagine 15KW would be big enough.

Latro

As primary fuel I use coal peas. It is smaller than singles but bigger than slack.
Last winter I paid E10 per 40kg bag. After the tax hike it will probably be E11 this year.

As I mentioned in my 1st post I have 200sq meters house and my 19kw is too big for that.
In your case I'd take smallest possible option(probably 14-15 is the smallest you can get).

Ideally you want small boiler with relatively big hopper(about 200kg) so you can refuel as rarely as possible, in my case its 10-12 days.
When you get one ask the seller if they can get you something custom made. Small boiler(14kw) with biggest hopper(30kw type) available as they are interchangeable within same model range.

Latro

I forgot to mention that you can burn wood, cardboard etc as 2ndary fuel but I gave up on that as it requires frequent visits into the garage.
Oh and the garage has become the warmest place in the house at about 25 degrees constantly.

zoom_cool

Hi Latro

Thanks very much for all this detail it has been a great help is the Pea coal hard to get do you buy in bulk have you contact details for supplier? Also where did you purchase the boiler?

You can PM me any detail which you cant post.

Thanks again.

nophd08

Hi all, I also have the Defro boiler, I went for the 25kw to allow for small bit of heat loss between garage and house, also the differences between 15 and 25kw is very minimal, bigger has more water capacity which I think acts as a bit of a buffer. Its cheap to run but does need looking after, loading cleaning etc, and I think you need a decent size garage and ways of working with bulk coal deliveries, if buying in bulk, which is the cheapest way. All in all its a godsend heatwise. I'm heating a 2000sqft bungalow, 24hr heat for about €400. Ie its an automatic feed boiler.

zoom_cool

nophd08 wrote: »

Hi all, I also have the Defro boiler, I went for the 25kw to allow for small bit of heat loss between garage and house, also the differences between 15 and 25kw is very minimal, bigger has more water capacity which I think acts as a bit of a buffer. Its cheap to run but does need looking after, loading cleaning etc, and I think you need a decent size garage and ways of working with bulk coal deliveries, if buying in bulk, which is the cheapest way. All in all its a godsend heatwise. I'm heating a 2000sqft bungalow, 24hr heat for about €400. Ie its an automatic feed boiler.

Thanks for the info can you pm me the details of where you get your coal.

tinofapples

nophd08 wrote: »

Hi all, I also have the Defro boiler, I went for the 25kw to allow for small bit of heat loss between garage and house, also the differences between 15 and 25kw is very minimal, bigger has more water capacity which I think acts as a bit of a buffer. Its cheap to run but does need looking after, loading cleaning etc, and I think you need a decent size garage and ways of working with bulk coal deliveries, if buying in bulk, which is the cheapest way. All in all its a godsend heatwise. I'm heating a 2000sqft bungalow, 24hr heat for about €400. Ie its an automatic feed boiler.

Sounds good, what was purchase and installation cost ? Been mulling over this for awhile now and will more than likely put one in when I decide to pull out the wood pellet boiler.

NIMAN

Also mulling over purchasing one of these boilers/burners for the garage.

I have been searching a few threads for info on these, and Latro is giving some great info on his/her system.

The one question I haven't seen asked is about smoke. Do they churn out much smoke out of the garage? Would hate to have black smoke belching out of my garage for large parts of the day.

Latro, you still around?

Latro

Hi.
I'm not sure what you mean.
Smoke from the flue or smoke from the room it sits in?
If everything is set correctly there should be little to no smoke at all visible from the flue.

DrPhilG

Another thread bump here.

I'm looking at one of the Defro slack boilers now. House is 184 square metres, 1980 square feet.

The garage is maybe 25-30 feet from the house so I'm thinking of the 24kw one.

Anyone have any more experience to share?