4 Small Boilers or 1 Big one??

[Deleted member 108845]

Hi, just bought our first house which is a georgian tereace with 3 storeys + cellar & attic. It's about 70 sq m per floor, with the ground and basement both having a 20sq m rear extension.

We might turn it into flats in years to come, but for the next 6 years it will be our home. The question is...should we have one big boiler or put a small combi on each floor?

If we did one big boiler should we zone each floor so each floor/flat could be hooked up to a combi in future?

What's the pros and cons of either option in terms of initial and running costs? Any other things we should take into consideration so we can make an informed choice?

It would be great to hear some professional opinions on this!

 

[king of pipes]

I would employ a heating consultant company to design a bespoke heating system for you, with energy saving controls to ensure you meet all the current regulations and end up with feul efficient system capable of supplying the property and your future planned project. Kop

 

[Deleted member 108845]

That sounds very expensive!

 

[snowhead]

That sounds very expensive!

So does fitting a badly designed uneconomical system

 

[Deleted member 108845]

So does fitting a badly designed uneconomical system

And I couldn't achieve a well designed, economical system with research and the help of you fine fellows?

 

[Stu-B]

It’s very complex, if you get it wrong it’ll cost you big in the long run. you may not even have a big enough gas supply into the property to run 4 small combis at max rate.
As others have suggested, get a design pro involved from the start.

 

[snowhead]

No, there's far too many variables.
And it needs a full onsite survey.

Just a few;
Total heat loss for whole building.
Heat loss per floor if zoned / timed /separate boilers /hot water storage /combi.
Available space for boiler /boilers.
Suitable exit for flues from that / those spaces.
Available pipe runs.
Typical demand for heating /Hot water per / floor /building
Installation and maintenance costs of single verses multiple boilers (2 , 3 or 4).
Return on investment for system/s.
......

You've just paid somewhere between £100k and £400k? for the house, don't scrimp on the fitting out.

 

[Brambles]

I agree with KOP and those who posted whilst I typed this missive!

A couple of points.

If the property is Listed, talk to the Local Authority before you consider any form of conversion.

Spending a grand with a local architect to develop preliminary options will give you a good insight into what can and cannot be achieved. Generally, the minimum living area for a flat is 37m2 - that excludes communal areas and access. Most Local Authorities require it to be above 40m2.

You either keep it as a house, convert to HMO or studio apartments / flats. It is not a simple change to move from one category to the other.
In my experience ( in Oxford) once you propose a conversion the Local Authority steer you to studio apartments - it dramatically increases their Council Tax revenue!

From where you are starting, ensuring that the cellar is properly tanked, whole house insulation and draft proofing are just as important as the heating system.

Look at the cold water inlet and ensure that it is configured to take in the highest pressure and flow available in your area.

Conversion of the property to flats/ bedsits in the way you propose will bring in a number of regulations for multiple occupancy properties : fire resistant doors, proper fire alarm system to name just two. Each unit would have to have it’s own wc, bath/shower and means of cooking to receive planning approval as a studio flat. The upper floor may require a secondary means of escape before conversion is allowed. Heating and HW does not have to be independent.

In summary, conversion to a House of Multiple Occupation (HMO) is much more straightforward than to studio apartments or flats.

You see a lot of poor conversions around, but over the past year the two Local Authorities I deal with dive right into the detail of domestic dwelling conversions.

Be aware that the fines for not complying with the HMO regulations are enormous ( well into 5 figures).

From the heating perspective:

I would design it as a whole house system - using a system boiler and unvented hot water. Zone each room using Honeywell Evohone, which allows each radiator to be an independent zone.

I am sure that you knew all this anyway

 

[Riley]

And I couldn't achieve a well designed, economical system with research and the help of you fine fellows?

For free you mean then? Seriously buddy if you’re going to do such a big project do it properly and pay the proper rate

 

[Millsy 82]

1st thing to do is stop watching homes under the hammer and things like that and start looking at the sector you will be either hoping to enter or sell to.

The rental game is going to start changing over the coming years.

A cap on fees from letting agents means they will look to get their money from somewhere else (that would be you)

3 year tenancies are likely to be rolled out in the capital then more than likely the rest of the country in the coming years.

The lack of enforcement for non payers, your looking 3 months before you can start an eviction process a local council that will back the tenants and tell them to stay put until you can get a bailiff in, which will probably be 7-9 months down the line all of which will be paid for by you because the tenants wont of paid a penny.

Then there is the house obviously the heating is the least of your worries. What about electrics, fire regs etc.

So my advise to you is stop playing property developer and decide 100% what you want to do then do that.

 

[Deleted member 108845]

At this stage we have no plans to convert into flats. It is our home, currently with no electrics and no central heating. All we want to achieve for now is to sort those two things but to do it in such a way that would be conducive if and when it was turned into flats.

I realise there are many considerations 're conversion but those are decisions and costs for the future. The electrics and heating need doing now.

We are on a terrace of five houses and ours is the only one not to have been converted to flats, so whilst it would be a shame to see it lose some character when converted, the building does lend it's self to flats very well. We just want to do the heating right first time so we don't have to undo it if it is converted in the future.

 

[Riley]

At this stage we have no plans to convert into flats. It is our home, currently with no electrics and no central heating. All we want to achieve for now is to sort those two things but to do it in such a way that would be conducive if and when it was turned into flats.

I realise there are many considerations 're conversion but those are decisions and costs for the future. The electrics and heating need doing now.

We are on a terrace of five houses and ours is the only one not to have been converted to flats, so whilst it would be a shame to see it lose some character when converted, the building does lend it's self to flats very well. We just want to do the heating right first time so we don't have to undo it if it is converted in the future.

So take the advice you’ve been given and get a professional in to get it designed correctly the first time

 

[Deleted member 108845]

So take the advice you’ve been given and get a professional in to get it designed correctly the first time

By professional do you mean a heating engineer? The problem is the vast difference in the quote spec...

1. 40kw combi serving while house
2. 2*24kw system boilers + 300l cylinder
3. 30kw system boiler + 210 cylinder

Non of the three wanted to talk about doing a combi on each floor, but this seems to me to be sensible for if and when each floor is a flat.

I would like the know the advantages and disadvantages of one big boiler over 3 small ones in terms of things I should be considering.

 

[Riley]

You are going in circles mate you need to decide what it is you want to do, if you are going down the HMO route then one big boiler and a huge hot water storage option would be sensible, if you are going down the flat route then yes a boiler for each flat would be sensible, if there is a chance you are going to keep it as a family home then design it once and future proof it with the right size boiler and hot water cylinder for you and your family and put your feet up and enjoy it

 

[Deleted member 108845]

You are going in circles mate you need to decide what it is you want to do, if you are going down the HMO route then one big boiler and a huge hot water storage option would be sensible, if you are going down the flat route then yes a boiler for each flat would be sensible, if there is a chance you are going to keep it as a family home then design it once and future proof it with the right size boiler and hot water cylinder for you and your family and put your feet up and enjoy it

Thanks Riley.

So maybe one big boiler and cylinder. Zone each floor and then if in future it's turned into flats we can install combis then and hopefully the pipework can be easily adapted.

With each floor being zoned, does anyone know if there should be a separate flow and return from the boiler to each floor or 1 flow and return with each floor branching off with a zone valve on each floor?

 

[Brambles]

Joshua,

What I have tried to say in a long winded way is that the conversation of domestic dwellings to flats is a lot harder now than it was three years ago. It is much much easier to convert a commercial property to flats ( the legislation is much less rigid).

If you want to minimise changes in the future, then design the heating, plumbing and electrical systems around your proposed layout of flats - then live in it as a house - with multiple consumer units, wc’s, showers et al!

Not sure about the four combi boilers though.

Also be aware of the terms of any mortgage you may have on the property. The law that lenders must comply with is different for residential and buy to let - most lenders (in my experience) will require you to change mortgage type, before the conversion, if domestic residential is transformed into flats. There is also obviously the issue of then determining the point from which capital gains tax is assessed fir any future sale of all or part of the property.

Millsy - had some good, if not blunt advice - the past two years has seen an enormous change in both building regulation for conversions and the tax treatment of both income and capital gain on property in both the buy to let sector, conversion to flats and second homes.

The days of a quick conversion, move in, call it your main home and sell on ( pay no capital gains tax) move into the next flat, call it your main home... are now long gone. The game has changed, but perhaps worse than that Estate Agents and Solicitors all now have a legal obligation to report suspicious transactions - so they report every transaction in the conversion and private rental sector.

 

[Riley]

And this is where you need somebody that understands system design to properly pipe size and design it in such a way that everywhere is going to get even heat, decide where your zone valves are going to be for easy access and future proof it should you require combis in the future

 

[Deleted member 108845]

And this is where you need somebody that understands system design to properly pipe size and design it in such a way that everywhere is going to get even heat, decide where your zone valves are going to be for easy access and future proof it should you require combis in the future

And are all heating engineers equal in their knowledge of pipe sizing and design. Someone in the thread suggested a heating consultant, but they seem to be few and far between when I've searched google.

 

[Riley]

Decide what you want it to look like. Then get three quotes see what each one suggests. Bit down with them discuss your potential future plans you will be able to judge by their reaction whether they seem confident in it Or not. Correctly sizing the boiler radiators and pipework is not rocket science but it is quite a precise process if you are looking at zoning and various different controls throughout the house then you are going to need somebody with a lot of experience. For example steer well clear of anybody that thinks the whole house can be done with a large combi boiler

 

[Millsy 82]

My advice is

40kw combis should be banned and avoid. If you need a 40kw combi and have the flow rate for them get an unvented.

You have 2 people wanting to fit 48kw or 30kw that is a huge difference probably 2 2up 2 down heating systems between the 2 so ask them for how they sized it because something isn't right.

If you are going to convert it then as they are only small flats fit an unvented in each and a couple of cheap electric heaters job sorted. Probably the same install costs of a combi and cheaper maintenance and easy/ cheap to replace.

 

[ShaunCorbs]

If your planning on splitting later on then your going to need a new gas meter

Standard gas meter will supply 70kw including all cooking and supplementary heat eg gas fire etc

So you can only have 3 24kw combis maximum

Meter swap will cost you big time thousands