Are combination boilers any good - does hot water come out the taps fast enough

2010

scattycat1 wrote: »

Hi. We had a combi boiler installed in 2006 and honestly it was the best decision we could have made. Hot water is almost instant and it makes a great shower too. The house heats up very quickly even when we've been away for a few days and the house is very cold. Nothing has gone wrong with it in the 3.5 years we've had it, and I would definitely recommend a combi.
I hope that helps.

Have you had it serviced and what made you go for it.

From what I can gather every time someone enquires about a new boiler the cry from the sellers and installers is combi.
Is this the easy option or the only option?
Out of interest DAK what the builders put in new properties?

Cardew

I have both boilers in my place(the combi in an annex).

To me it is a no contest - the combi loses!

Those who say they get instant hot water from a combi is almost certainly because they have one of the models that have a reservoir in the combi(a tank) This is to overcome the inherrent disadvantage of combis - that hot water takes a long time to come through to the taps.

Of course keeping this reservoir warm uses gas, this is why some models have an economy switch which removes this facility - at the expense of long waits for Hot water.

There is no question that combi flow rates are reduced in winter. Look at the spec of any combi and it states it will raise the temperature of the input water by xx degreesC at a flow rate of y litres. Well at this time of the year mains water can be 3C

money2009

Thank you very much indeed to everyone for the information - this really is very useful. We have approached three companies and all three have given different advice - sitting here wondering whether we should keep the warm air!

Once again, many thanks indeed.

jenny2009

money2009 why are you considering changing your warm air heating?

I have warm air heating that is 18 years old and every time I get it serviced the BG engineer tells me it is needing replaced and wants to give me a quote for radiators as he says they will be more efficient.

How? Heat water, pump round radiators to heat air or heat air. what is more efficient?

I use about 18,000 kWh of gas a year for heat and hot water costing me about £600, how much would that be reduced if I got radiators?

I probably costs £400 to heat the house and £200 for hot water.

so if I saved 20% overall that would be £120 per year, if I paid £3000 for a new heating system it would take 25 years to recoup the cost of the new system, but, how long would it be before I needed to replace the boiler?

So ask yourself, why am I going to/want to replace my warm air heating system?

Jen

jenny2009

another question that probably warrants a thread on its own but I will slip it in.

what would be the consumption of gas, using a combi boiler, to heat water for a 15 min shower and a bath of hot water every day?
preferably in kWh.

At present we use approx 21 kWh which includes a pilot light that consumes 3 kWh per day?

Jen

Cardew

jenny2009 wrote: »

another question that probably warrants a thread on its own but I will slip it in.

what would be the consumption of gas, using a combi boiler, to heat water for a 15 min shower and a bath of hot water every day?
preferably in kWh.

At present we use approx 21 kWh which includes a pilot light that consumes 3 kWh per day?

Jen

Most modern boilers(both types) don't have a pilot light - they use electric ignition.

The other factors to consider are

The efficiency of the combi boiler(should be around 90%) versus the efficiency of your boiler.

If the combi keeps a reservoir of hot water - see post above.

The length of pipe run from the combi to the tap(s) versus the current set up.

How much heat is lost from your HW tank(in normal use about 2kWh or less) a day. In winter that heat is not lost as it warms the fabric of your house.

It will certainly be less consumption than your present set up, but by how much????

jenny2009

It will certainly be less consumption than your present set up, but by how much????

Exactly, not enough to justify paying out £3000 and the lost room space and upheaval of putting in radiators.

Jen

richardc1983

Keep the warm air system... if you are happy with how it delivers the heat now then why change it!