What type of hot water system to have?

[Zebra579]

I am wondering which type of boiler to have. There is currently no central heating or water heating system in an old cottage which I am renovating.
It's a tiny place and my hot water requirements are minimal. I am intending to install radiators, but am wondering about how to create hot water for the bathroom and the kitchen sink.
The obvious solution would be a combi boiler, as I have a gas supply. But as combi boilers seem to have quite a bad reputation for long term reliability, I am wondering about instantaneous electric water heating, as the hot water requirements are so small.
Then I would only need the boiler to do the central heating.
Is there a type of boiler which does just central heating and not hot water, and if so, are there any advantages to having one? For example, siting the flue is a bit tricky - would the requirements be any easier than for a combi? Are the boilers any smaller or easier to maintain? Are they more reliable? More efficient?
Many thanks

 

[mogget]

Does the cottage have any bathing / washing facilities?

 

[petertheplumber12]

Any gas boiler of any type will have the same flue problems, they are given the opportunity of using a plume management kit to help get rid off the exhaust you can get a heating only boiler and if so I would suggest a system boiler then you don't need a tank Intergas make boilers like that and they are reputed to be very reliable, you can then have an instantaneous water heater for hot water under the sink or over the sink.

 

[Zebra579]

Does the cottage have any bathing / washing facilities?

A temporary bathroom with a temporary power shower. All very primitive I'm afraid, and doesn't get used as often as it ought to!

using a plume management kit to help get rid of the exhaust you can get a heating only boiler and if so I would suggest a system boiler then you don't need a tank Intergas make boilers like that and they are reputed to be very reliable

OK, I'll look into that - plume management kit; system boiler; Intergas - googling all that now. Thanks!

 

[simond]

A properly installed combination boiler is the obvious answer. Electric heating will cost 300% more to run and a heat pump will cost 300% more to install.

When fitted by an accredited installer both Worcester-Bosch and Vaillant are prepared to back up their boilers with a 7yr on site warranty.

Intergas, on the other hand, sell a handful of boilers in the UK each year, and have virtually no warranty offering. You are in the hands of your installer because they are not established or financed enough in the UK to have a nationwide responsive service team.

Unlike others here I'm not convinced they are any better than most other boilers, the combi with the combined heat exchanger with no diverter and plate is an old idea, given up by most other manufacturers years ago.

If you are an internet jockey, you could easily be fooled into thinking that the Intergas/Atmos is an innovation - look up old Ferrolis and Worcesters and you will find otherwise.

If Intergas ditched the Wilo pump I might take a look; but any boiler with one of those is going to be a problem in the UK.

 

[flameport]

It's a tiny place and my hot water requirements are minimal.

How tiny? How many radiators & hot water outlets?

A combination boiler will inevitably be grossly oversized for the radiators, and if the hot water requirements and size of this place really are tiny, a gas boiler and radiators may not be appropriate regardless of what type/make/whatever.

Electricity will certainly cost more than gas. However the lack of a boiler and radiators does not automatically mean electric heating.

 

[Zebra579]

It's a tiny place and my hot water requirements are minimal.

How tiny? How many radiators & hot water outlets?

Well, the house is old, and although small, it is largly solid wall with a lot of external wall for the space, which means that the BTU calculations actually come out quite big. Using the online calculators:
Living room/ kitchen: 11100 BTU
Bathroom: 2397 BTU
Study: 2218 BTU.
Total 15715 BTU.

Hot water = kitchen sink; shower; basin, maybe bath.

 

[Zebra579]

A properly installed combination boiler is the obvious answer. Electric heating will cost 300% more to run and a heat pump will cost 300% more to install.

When fitted by an accredited installer both Worcester-Bosch and Vaillant are prepared to back up their boilers with a 7yr on site warranty.

Yes a combi is the obvious solution. It's just that 7 years of reliability doesn't seem very long. I also hear in the news that gas prices will be inevitably rising, whereas we may perhaps be able to find new ways of generating electricity in the long term.

I plan to grow old here, and don't want to be installing a short term solution or one which will grow obsolete! Would you think these concerns are outweighed by the short term savings of having a combi?

 

[picasso]

Small system boiler and unvented cylinder if you have the room and water pressure/flow, you will also have an electric back up for the hot water .

 

[Elkato531]

If you bought a car, you'd expect the manufacturer to provide a warranty and repair it if it broke down within that period. With regular servicing and occasional maintenance and repair costs you'd expect many more years of service. A boiler and heating system is the same. The days of cast iron boxes that will last 25-30 years without a service are long gone. All modern boilers will have ongoing costs and even the best manufacturers have problems.

If you are planning to grow old in the place you need to think about future hot water usage. You may even meet someone who expects you to wash more often.

More seriously, a combi boiler supplies your needs in one box and as you only heat the water you use is probably going to be your most economical and simplest option.

 

[picasso]

The heat load for his house is around 5 kw, even the smallest combi will cycle with such a small heat requirement.

 

[Zebra579]

"Small system boiler and unvented cylinder if you have the room and water pressure/flow, you will also have an electric back up for the hot water ."

No, definately no room for a cylinder.

"You may even meet someone who expects you to wash more often."



"The heat load for this house is around 5 kw, even the smallest combi will cycle with such a small heat requirement."

What does this mean - the combi will cycle?

 

[flameport]

"The heat load for this house is around 5 kw, even the smallest combi will cycle with such a small heat requirement."

What does this mean - the combi will cycle?

It means a combination boiler is totally unsuitable, as it would typically be 30-40kW which is rather obviously a lot more than the 5kW heating requirement.
It will switch on and off constantly, wasting vast amounts of gas and will wear out in no time.

If your heat calculations are correct, then in watts:
Living room/ kitchen: 3.3kW - Typical output for a normal sized gas fire. Or perhaps a wall mounted gas heater. Won't be needed when cooking in the kitchen.
Bathroom: 700 watts - a 1kW wall mounted fan heater would be more than adequate.
Study: 650 watts - a small oil filled electric radiator on wheels, available from Argos or wherever. Or get a 4kW gas fire in the living room and leave the connecting door open.

If you don't want a bath, then hot water can be provided with an electric shower, and a 10 or 15 litre undersink heater for the basin and kitchen sink.

 

[JohnD]

would you like a multifuel stove?

it could heat a cylinder, when running (mostly in winter)

consider the cost of installing a gas system, and the cost of installing electric.

How many years would it take for the higher running costs of electricity to reach the cost of installing the gas system?

 

[Zebra579]

No that can't be right flameport, I need much more heat than that. Thank you for taking the time to work all that out, but it doesn't seem right to my inexpert eye. Perhaps my BTU calculations are wrong.
For example 11000 BTU needed in the kitchen/living room requires two double panel radiators each 700mm high and 800mm wide (5478 BTU each in Screwfix). That must be more than a normal sized gas fire.
JohnD I already have a woodburner, that's how I'm getting through the winter! But I have nowhere to put a cylinder.