Which boiler system for a 4 bedroom house?

Adam

Adam

Adam

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The house I have moved in to recently has the original 15 year old boiler. I'm not aware of the history other than it being serviced every year (although I don't have any documentation to support this).

I understand a combi boiler isn't neccessarily always the most appropriate choice, especially for large houses. The house is 4 bedrooms with a family bathroom, en suite and downstairs toilet. It currently has a conventional system (?) with a hot water cylinder, cold water tank and header tank in the loft.

The boiler is currently mounted in a cupboard in the utility room and the hot water cylinder takes up a huge cupboard upstairs. We could either free up some space in the kitchen or in the cupboard depending how we proceeded.

I have been looking at Valliant Ecotec or Worcester Bosch combi boilers but is this the best option?
 
Any larger properties I deal with we specify conventional boilers. Its more to do with the water requirements for the different facilities though.
 
Combi is fine for large properties provided you have a large enough boiler to fuel the rads - look at how many BTU's your rads are and then how many BTU's the boiler can put out.

And for all you new fangled kids working in Kw, my car gets 30 rods to the hogs head and that's the way I likes it :D
 
Valiant my first choice, easy to service.

The higher the boiler output, usually higher the hot water flow, you could also look at having megaflow cylinder with the boiler, would give you mains pressure hot water.

Water header tanks in lofts is old fashion nowadays, rip the lot out.

Probably looking at Valliant ecotec plus 837 or 831 has a lower hot water flow & ch output, if decide against a megaflow.
 
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Sorry to hijack but as I was calling around to get quotes for fixing my boiler this morning, I asked one knowledgeable sounding guy for his opinion on a replacement boiler brand.

I knew of Worcestershire Bosch and Valliant having a good reputation but his recommendation was Baxi. I've never heard of them before but he backed up his recommendation by saying they offer a 10 year warranty (5 more than Bosch/Valliant) and fixing them was easier/cheaper than those 2. If I recall correctly I think he said the Bosch were more time consuming to repair (I'm guessing in comparison to Baxi/Valliant).
 
Not a combi

I've worked for multiple Housing Associations and they have all banned Combi boilers in anything above 2 bed apartments.

They must have hundreds of thousands of boilers they maintain and Combi boilers cost them too much in comparison with traditional.

Don't buy one.
 
Not a combi, no matter how big. And unlike what has been mentioned above it has nowt to do with radiators. I'm not talking about repair costs either. This is purely down to performance and being happy living with the system.

The only time I would think about putting a combi in a four bed would be if the house was only occupied by two people or the combi had a stored water capacity. Otherwise upgrade the system you have to a small (correctly sized) condensing boiler with a UVHW cylinder, preferably with a blending valve, S-Plan or S-Plan plus depending on the size of the house. The only other reason to go for a combi would be to save space or cut corners on cost. Your choice. And just my opinion. ;)

Mick
 
If you want to be able to use more than one shower or hot water tap at the same time you should go for an unvented cylinder and system boiler, this is dependant on your incoming water pressure and flow rate which would need to be measured.

I recently replaced a combi with a Vaillant system boiler and unistor unvented cylinder and it is superb, I had friends staying recently that resulted in three showers being used at the same time which the system did without issue.

I also went with the Vaillant weather compensating controls which adjusts the radiator flow temperature to the outside temperature so the warmer it is the lower the flow temp which keeps the flow temperatures as low as possible so the boiler is always in full condensing mode which is it operating at peak efficiency. It also allows you to have a different flow temperature for the hot water cylinder so I can maintain the rapid reheat of the cylinder, non Vaillant controls do not allow this. I have seen a 30% drop in my gas usage over the 24 year old combi system.
 
Imy said:
Sorry to hijack but as I was calling around to get quotes for fixing my boiler this morning, I asked one knowledgeable sounding guy for his opinion on a replacement boiler brand.

I knew of Worcestershire Bosch and Valliant having a good reputation but his recommendation was Baxi. I've never heard of them before but he backed up his recommendation by saying they offer a 10 year warranty (5 more than Bosch/Valliant) and fixing them was easier/cheaper than those 2. If I recall correctly I think he said the Bosch were more time consuming to repair (I'm guessing in comparison to Baxi/Valliant).
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Sort of true, Baxi ironed out the minor issues with the Duotec Mk1 and ended up with a cracking boiler for the price (stainless heat exchangers and simple design and reliable, cheap to repair) They then brought out the Mk2 which was and is a piece of junk, and still is. Realising they messed up, they put the Mk1 back on the market at a great price and with good warranty. And so unless you need anything singing and dancing then go for a DuoTec Mk1 boiler. A great buy for the price and peace of mind warranty, and not expensive to repair.

Mick
 
Dangerous Dave said:
If you want to be able to use more than one shower or hot water tap at the same time you should go for an unvented cylinder and system boiler, this is dependant on your incoming water pressure and flow rate which would need to be measured.

I recently replaced a combi with a Vaillant system boiler and unistor unvented cylinder and it is superb, I had friends staying recently that resulted in three showers being used at the same time which the system did without issue.

I also went with the Vaillant weather compensating controls which adjusts the radiator flow temperature to the outside temperature so the warmer it is the lower the flow temp which keeps the flow temperatures as low as possible so the boiler is always in full condensing mode which is it operating at peak efficiency. It also allows you to have a different flow temperature for the hot water cylinder so I can maintain the rapid reheat of the cylinder, non Vaillant controls do not allow this. I have seen a 30% drop in my gas usage over the 24 year old combi system.
Click to expand...

This ^ No point in doing things by halves unless your after a cheap fix or flogging the house.
 
Dangerous Dave said:
If you want to be able to use more than one shower or hot water tap at the same time you should go for an unvented cylinder and system boiler, this is dependant on your incoming water pressure and flow rate which would need to be measured.

I recently replaced a combi with a Vaillant system boiler and unistor unvented cylinder and it is superb, I had friends staying recently that resulted in three showers being used at the same time which the system did without issue.

I also went with the Vaillant weather compensating controls which adjusts the radiator flow temperature to the outside temperature so the warmer it is the lower the flow temp which keeps the flow temperatures as low as possible so the boiler is always in full condensing mode which is it operating at peak efficiency. It also allows you to have a different flow temperature for the hot water cylinder so I can maintain the rapid reheat of the cylinder, non Vaillant controls do not allow this. I have seen a 30% drop in my gas usage over the 24 year old combi system.
Click to expand...

Valliant 470f weather compensator is great, well worth the extra outlay, read an article in one of my trade mags, that you can easily make gas savings of something like 23% minimum with the boiler correctly set up, with you quoting 30%, I must get & one fitted for my boiler.
 
Nightglow said:
Valliant 470f weather compensator is great, well worth the extra outlay, read an article in one of my trade mags, that you can easily make gas savings of something like 23% minimum with the boiler correctly set up, with you quoting 30%, I must get & one fitted for my boiler.
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The 470f is a good system, I would add that the lower the heating curve doesn't mean the lowest gas usage as the house heat up time is longer. I found I could run the system down to a curve of 1.4 as I have suitably oversized radiators but I used less gas using curve 1.7 as the heat up time was reduced enough to cover the extra gas that was being used to run the flow temperature higher. It took a few weeks comparing the gas usage to the curve used but once settled on the correct curve I haven't had to change it.
 
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Slight thread hijack..

We are currently looking to move our boiler to the loft to free up room in the utility room and prepare for an extension in a few years. We currently have a combi boiler and no hot water tank.

We are planning to extend from 3 bed/1 bathroom to 4 bed/2-3bath/shower rooms so guess having a water tank will be recommended for multiple people showering at once.

What would you guys recommend?

I read something stating a water tank with 2 coils is better as it will allow future addition of solar hot water or 2 feeds from the same boiler but not sure what the benefits of that are. Also, are the weather compensating controls required if you have a smart thermostat such as Nest/Hive/Tado?
 
maccapacca said:
Not a combi

I've worked for multiple Housing Associations and they have all banned Combi boilers in anything above 2 bed apartments.

They must have hundreds of thousands of boilers they maintain and Combi boilers cost them too much in comparison with traditional.

Don't buy one.
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Yeah because housing associations are a mark of quality...

There's nothing wrong with a high output combi, are you really going to get more than 2 people showering at once in a 4 bed?
 
Thanks for the comments, I'm swaying towards the system boiler and moving everything to the cupboard upstairs. The unvented cylinder and boiler should hopefully fit in the cupboard upstairs as everything seems smaller than we have now. Thanks for your input!
 
NightShadow said:
Slight thread hijack..

We are currently looking to move our boiler to the loft to free up room in the utility room and prepare for an extension in a few years. We currently have a combi boiler and no hot water tank.

We are planning to extend from 3 bed/1 bathroom to 4 bed/2-3bath/shower rooms so guess having a water tank will be recommended for multiple people showering at once.
Click to expand...

Adam said:
Thanks for the comments, I'm swaying towards the system boiler and moving everything to the cupboard upstairs. The unvented cylinder and boiler should hopefully fit in the cupboard upstairs as everything seems smaller than we have now. Thanks for your input!
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If you have a large 3 or 4 bed with 2-3 baths/showers, I would prefer a unvented cylinder & boiler, I consider it a better option than having a large output combi.
 
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FlyingFish said:
Sort of true, Baxi ironed out the minor issues with the Duotec Mk1 and ended up with a cracking boiler for the price (stainless heat exchangers and simple design and reliable, cheap to repair) They then brought out the Mk2 which was and is a piece of junk, and still is. Realising they messed up, they put the Mk1 back on the market at a great price and with good warranty. And so unless you need anything singing and dancing then go for a DuoTec Mk1 boiler. A great buy for the price and peace of mind warranty, and not expensive to repair.

Mick
Click to expand...

Some great insight thanks. I had read later on online that Baxi wasn't so great on reliability but that kinda clears it up.
 
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