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Replacing boiler - stick with hot water tank or heat on demand


Distinguished Member
Hi All
Our Ideal Standard gas boiler is 20 years old, so is probably about due for replacement. What's the current consensus on heating, should we be looking to just replace the boiler or do we go for a heat on demand system instead?

We are a family of 3/4 (daughter at university) and have a 20 year old home, so it's reasonably well insulated.

Not looking at heat pumps or under floor heating etc. just the best replacement route really.

Thanks in advance!


Well-known Member
Get a combi (on demand)
I had old boiler removed from the kitchen and the tank removed from the airing cupboard. The new combi (Ideal logic+) fitted in the airing cupboard where the tank used to be. You can also get rid of the header tank in the loft if you have one.
You should have a lot of free space left in the airing cupboard I put a few simple shelves in for bed linen etc.


Distinguished Member
Nothing wrong with the boiler at the moment, but we've only had it serviced once in 20 years... The exhaust fan needs a spot of grease each year but that's about all. I've just fitted a new 3 way valve and we had a new tank last year, but otherwise all is good.

just thinking ahead really. We do occasionally run out of hot water, but it heats up in about 20 minutes, so no real drama. I guess it's about what will be the most economic to run over 5-10 years, factoring in the cost of the boiler, any changes to the current system and running costs etc.

Greg Hook

Moderator & Reviewer
I'd go for Combi.

If your boiler is 20 years old, a new one will be more economical.


Distinguished Member
But if the old one is still working whats the length of time before your in profit from the running saving?

We had 25year old boiler that i was keeping limping along, but as i started to work away more i wanted something more reliable for the family.


Well-known Member
I had a heat only boiler replaced with the same. My worry is if a comb breaks down you have no hot water. About a year after installation it broke and the manufacturer took 2 weeks to fix it under warranty. Thankfully I still had the immersion heater for hot water.


Distinguished Member
had a new worchester combi fitted earlier in the year..after my valient ended up being too expensive to fix
.....gas bill ended up being about a tenner a month cheaper

after a lot of research and some expensive quotes from local firms i ended up going with 'boxT' who carry out nationwide fittings

new worchester combi boiler..with free magnetic filter...and nest control

£1700 all in ....plus 10 year guarantee as long as you get it serviced every year

as much as i'd like to help out local tradesmen i could'nt afford to pay their prices which were double that
very happy with the price and service.


Well-known Member
had a new worchester combi fitted earlier in the year..after my valient ended up being too expensive to fix
.....gas bill ended up being about a tenner a month cheaper
Good point, the new boilers are very efficient, you’ll make a huge saving over the life of the boiler.


We replaced our 1970s boiler/tank with a Combi 2 years ago and haven't looked back. The house is warmer, the shower is more powerful (it's a bungalow and hot water pressure was hopeless) and even though it's being used more costs have been reduced significantly. Oh and we now have a handy cupboard to keep the vacuum cleaner in :)


We had to replace an old Valiant Boiler in the UK when the yearly maintenance contract with British Gas was being carried out. They wanted to much for a replacement so found a local company reccomended on a traders site...cannot remember the name of it....Valiant we were happy with and it was under £2000 so seemed a decent quote. We kept the same rads and soon discovered some were not heating up as they should..bled them and it made no difference. Phoned the company and they tried to palm us off with excuses/rubbish reasons basically. He said if he has to attend the charges per hour would be...and we would ned thermostats to each rad...we already had them though oldish...I could not believe the conduct...Go with a reccomendation that you know something about..friends and family neighbours that have had good service experience.The Boiler was great though and you could run it as low as you wanted so zero degrees I hit the on all night on very low...just warm and cosy not hot... and the bills were so much lower like others have said.We had to have the system drained again because it was not done correctly....so no more cold rads....

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