New Oil Fired Boiler - Condensing or Non Condensing

[baggy99]

I need to replace my duff oil boiler but having read a load of stuff, I am not convinced that a condensing unit is the way to go.

Convince me by all means, but:
- I'm not bothered by the legislation - I can work round that - I just want the most cost effective solution.
- I will be installing a 180 ltr thermal store/heat store WITH SOLAR INPUT and an Alpha pump.
- Big house, well insulated, 23 rads, but only 2 occupants, one bathroom, 1 bath of dhw used each morning.

My assumptions are:

- Solar input will mean the boiler won't run in condensing mode (if at all) during summer burns (insufficient temp diff)
- Ditto for spring & autumn 50% of time
- Boiler will hit max effeciency with full condensing ONLY in cold winter months when CH is on and there's no solar contribution.
So, I am paying £400 more for a boiler that only runs in condensing mode for 3 months a year??!! And it will be less reliable than a standard boiler? Makes the payback period closer to 20 years than 10. Not cost effective!

PLEASE feel free to correct any incorrect assumptions or add anything I have not considered. Thanks.

 

[Agile]

The first falacy is that you will get any payback at all on the solar element!

If you take into account the interest you are losing on the cost not being in the building society OR the cost of borrowing then there is no payback at all.

The saving from solar is about 3-4% in the best case and yours is one of the worst because you dont have enough people to use all the solar HW you can heat during the summer.

The plain financial facts are that you would be better off getting a condensing boiler and forgetting about the solar!

Pity about the planet though!

With simple controls and conventional settings what you are saying has some truth. This arises because to get the most out of solar the store is heated to about 80°.

However, with more clever controls you dont need to heat it up that hot with the boiler. It only needs to be at 60-70°C when heated by the boiler and that would allow it to be quite efficient.

You can clearly afford to help the planet so get the condensing boiler and solar!

If you want to save money then leave out the solar and just have the condensing boiler.

Tony

 

[Agile]

baggy99 Cheers Chris. Yes, the boler will be a condensing model, so it is great to know that the pump won't have to work as hard.
Would you recommend an Alpha? Are the smart pumps from Wilo (and others?) just as good, or should I stick to a genuine Alpha?

Just seen this you have posted previously!

You seemed sure it would be condensing then!

The Grunfoss Alpha would be a good idea if you have varying numbers of rads in service as it will save electrical power a little when only using the usual small number.

Tony

 

[simond]

If I were you;

I'd fit a Kidd Model 2 oil condenser - lifespan shown to be well in excess of 20 years (it was launched in 1983)

Fit a Honeywell Hometronic 16 zone temperature controller with HS80 rad valves

Throw solar in the bin

And look forward to enhanced comfort and energy savings. We are installing three of the above configs at the moment.

 

[simond]

Just read baggy's post again.

Why are you worried about 10yrs versus 20 yr payback time when you are putting in solar? As Agile says, taking the cost of money into account solar will never cost in, ignoring the value of money you'll be waiting 20-25yrs.

And if you think your solar will last 25yrs, may I choose to differ.

I think you are getting carried away with bumpf, rather than pragmatics. The best way to save money is by reducing the amount of energy you put into your house (insulation, zoning, temp control) and then reducing the cost of producing that energy (high efficiency boiler).

 

[baggy99]

Decisions, decisions....

Firstly, yes I was totally convinced on a condensing model, then I started reading a load of negative comments regarding actual savings, reliability, etc, etc.

Secondly, I like the idea of solar cos its free after its fitted (DIY costs pretty minimal - maybe £500/600?) BUT you are quite right to point out its potential lifespan. My boiler calcs assume the boiler will last 20-25 years, whereas I was assuming the solar would last forever, which is admittedly unrealistic..... How long would you give a solar installation? Do evac tubes last longer/shorter than flat plates?

Finally, I can't zone the CH without ripping up all the floors, since its all pre-installed and on a single circuit. Alpha pump and 60 - 70 deg TS should be easy though.

 

[simond]

Hometronic does not involve ripping the floor up, that's part of the benefit. It adds a motor to every rad valve controlled by RF..... and a PFM chip.

 

[gas4you]

If you think you are going to get a decent solar system for £500/600 then think again.

You would be looking at around £3500 for a reliable quality system and you will be lucky to save around £120-£150 per year. Solar is over-hyped, over priced and won't become vialble until there are grants of around 50% of the cost.

To make some savings the 180 litre store is not going to be big enough really.

 

[baggy99]

>> If you think you are going to get a decent solar system for £500/600 then think again.

I did! And I would be very interested to know why you think my figures are so far out? It will be a DIY job, as indicated. I will already have the TS with solar coil, as I mentioned, so in my innocence I assumed it was simply a matter of adding a panel, pipes, fittings, ev, pump & controller.

I haven't studied the panels in depth yet (was to have been a project for next year) but a quick search reveals that I can get a 2.75m sq panel (evacuated tube) for around £280, leaving another £320 for the remaining bits and pieces. What have I missed?

>> o make some savings the 180 litre store is not going to be big enough really

What size would you suggest? I thought I only needed a bit more than a bath-full, the idea being to run the bath in the morning and let the solar replen the TS during the day. Again, what have I missed?

 

[wilhelm]

try one of these baths in the morning

........

 

[oilman]

If I were you;

I'd fit a Kidd Model 2 oil condenser - lifespan shown to be well in excess of 20 years (it was launched in 1983) .............

Who also wrote something here, though I don't know what a "discerning client" is. Someone with loads of money and who doesn't care how it's spent, as long as they can talk about it at parties perhaps.

Look at these. They have near zero CO output when up to temperature, and are far better built than most. The heat exchanger is all stainless so you don't have a figure of 20 years like the Kidd. The HCC are very expensive, but make more sense than solar heating.

 

[simond]

We have looked into these Hellfire units, but I have never seen one installed. Have you installed one, Oilman, and what did you think of them?

Mr Barnnt Mills is well known for having the largest probiscus in the industry, but possibly also holds the highest opinion of himself. I found him a difficult man to get on with.

I don't know what a "discerning client" is. Someone with loads of money and who doesn't care how it's spent, as long as they can talk about it at parties perhaps.

A discerning client is a customer who recognises the value of quality engineering and longevity. Who appreciates that the dust to dust impact on the environment of a boiler that typically lasts in excess of 20 yrs whilst operating in SEDBUK A is minimal, compared to others.

Incidentally, in the link you attached, comments by a third party suggest that a Kidd flue is steel; I did not bother correcting him at the time but they are socketed welded aluminium.

Finally, the secondary HE in the Kidd is made of stainless and aluminium. If Mr Mills has been making that actual Hellfire CC model since 1987 and you have seen them still working in the field, please confirm.

 

[baggy99]

We seem to have moved off topic. Can gas4you (or anyone else with a view) please respond? Thanks.

>> If you think you are going to get a decent solar system for £500/600 then think again.

I did! And I would be very interested to know why you think my figures are so far out? It will be a DIY job, as indicated. I will already have the TS with solar coil, as I mentioned, so in my innocence I assumed it was simply a matter of adding a panel, pipes, fittings, ev, pump & controller.

I haven't studied the panels in depth yet (was to have been a project for next year) but a quick search reveals that I can get a 2.75m sq panel (evacuated tube) for around £280, leaving another £320 for the remaining bits and pieces. What have I missed?

>> o make some savings the 180 litre store is not going to be big enough really

What size would you suggest? I thought I only needed a bit more than a bath-full, the idea being to run the bath in the morning and let the solar replen the TS during the day. Again, what have I missed?

 

[oilman]

We have looked into these Hellfire units, but I have never seen one installed. Have you installed one, Oilman, and what did you think of them?

Installing a boiler is only connecting a couple of water pipes, an oil pipe, flue, a mains supply, a control signal, and a condensate drain, why is this such a big deal? within 2 minutes the CO level was 2ppm, and in 5 to 10 mins it drpos to zero. I think there ok.

Mr Barnnt Mills is well known for having the largest probiscus in the industry, but possibly also holds the highest opinion of himself. I found him a difficult man to get on with.

I'm not surprised you have difficulty with people if this is how you view them. I assume you think well of someone only if you are about to get large amounts of money from them. This type of personal comment is worthy of a cowboy plumber.

A discerning client is a customer who recognises the value of quality engineering and longevity. Who appreciates that the dust to dust impact on the environment of a boiler that typically lasts in excess of 20 yrs whilst operating in SEDBUK A is minimal, compared to others.

Then why do these people with such abilities spend large amounts of money on any number of products that use up the fuel they claim to save on their heating system? I judge people by their actions, including me, and we all spend money for the most part wasting resources.

Incidentally, in the link you attached, comments by a third party suggest that a Kidd flue is steel; I did not bother correcting him at the time but they are socketed welded aluminium.

I suggest you read the link again. It seems your reading ability is very near your spelling ability.

Finally, the secondary HE in the Kidd is made of stainless and aluminium. If Mr Mills has been making that actual Hellfire CC model since 1987 and you have seen them still working in the field, please confirm.

Made of stainless AND aluminium??? Interesting as these two metals are known for being quite distant in the galvanic series.

 

[simond]

Made of stainless AND aluminium??? Interesting as these two metals are known for being quite distant in the galvanic series.

Thats why Mr Kidd and Barnnt Mills design boilers and you just fit 'em.

Installing a boiler is only connecting a couple of water pipes, an oil pipe, flue, a mains supply, a control signal, and a condensate drain, why is this such a big deal?

You said it, but don't run yourself down too much.