Replacing old standard boiler

[bobbyt]

I have a 3 port valve Y plan system, with a hot water tank in airing cupboard and a cold water feeder tank in loft. I want to replace the old 25+ year old boiler. Should I just replace with a like for like condensing boiler or a combi. I understand to fit a combi involves a lot more work (more cost?), by removing tanks, pipes etc. Judging by my friends experiences, they tend to be more problematic.

We have three bedroom terraced house, one bathroom, no bath, electric shower cubicle and seven radiators. The present boiler is 15kw, but expensive to run as it has pilot light etc. and is old. It runs very well and all radiators have good heat output as I have recently had the system overhauled. Hot water tank is well insulated. I don't particularly want to lose the warm airing cupboard, (not a deal breaker), but finding it difficult on line, to decide which to go for, taking into account both installation and running costs, and best choice for my system. Flue is wall mounted, and new boiler will go in old position. Any advice on here to help me decide, including boiler manufacturer. Thank you.

 

[ShaunCorbs]

Tbh it’s upto you aslong as your cold water pressure is ok and your rads arnt out of the ark a combi will be fine

Baxi or main are good 7-10 on baxi and 5 on the main guarantees etc

 

[bobbyt]

Tbh it’s upto you aslong as your cold water pressure is ok and your rads arnt out of the ark a combi will be fine

Baxi or main are good 7-10 on baxi and 5 on the main guarantees etc

They are old rads as well, not the old big metal ones but slim ribbed panel ones. They were taken off and pressure flushed when the system was done recently. It was just an impression I had that combo wasn't very reliable and have to wait a while for hot water to come out. Also seem to need to be 30kw min, won't that push up my bills of using 30kwh when heating on our does it go on and off?

 

[pycoed]

They are old rads as well, not the old big metal ones but slim ribbed panel ones. They were taken off and pressure flushed when the system was done recently. It was just an impression I had that combo wasn't very reliable and have to wait a while for hot water to come out. Also seem to need to be 30kw min, won't that push up my bills of using 30kwh when heating on our does it go on and off?

If "It runs very well and all radiators have good heat output as I have recently had the system overhauled. Hot water tank is well insulated." then leave well alone! It can't cost much for gas for a 3 bed terrace, surely? All you will do is add a load of complexity & spend a couple of grand which will take years to recoup from the gas "savings", by which time you'll probably need a new boiler again😉

 

[ShaunCorbs]

They are old rads as well, not the old big metal ones but slim ribbed panel ones. They were taken off and pressure flushed when the system was done recently. It was just an impression I had that combo wasn't very reliable and have to wait a while for hot water to come out. Also seem to need to be 30kw min, won't that push up my bills of using 30kwh when heating on our does it go on and off?

Be the same as you have now hot water wise as you still have to flush the cold water out of the hot pipe etc

 

[bobbyt]

If "It runs very well and all radiators have good heat output as I have recently had the system overhauled. Hot water tank is well insulated." then leave well alone! It can't cost much for gas for a 3 bed terrace, surely? All you will do is add a load of complexity & spend a couple of grand which will take years to recoup from the gas "savings", by which time you'll probably need a new boiler again😉

Understand what you are saying, if heating is on 13 hours a day, it uses about 80 - 90 kWh a day, up to 2800 kWh per month. Is that ok do you think compared to a new boiler. Or as you suggest I won't recoup the cost anytime soon?

 

[gmartine]

What make and model is your old boiler?

 

[bobbyt]

What make and model is your old boiler?

It's a Baxi WM 51/3 RS I think.

 

[pycoed]

Understand what you are saying, if heating is on 13 hours a day, it uses about 80 - 90 kWh a day, up to 2800 kWh per month. Is that ok do you think compared to a new boiler. Or as you suggest I won't recoup the cost anytime soon?

I'd do a check on the efficiency of your existing boiler (80-85%?)& compare it with a new combi, say 95%. Then you can estimate your gas usage under the new system (say (95-80)/80 = 18% at best ) Compare that cost with the estimates you get for a change over (e.g. my son paid £3000 to change a combi boiler a couple of years back - plus two extra rads). Then you can take a view as to the payback period.
Everyone has different views on things - mine is always keep it simple! I just really wish I had my own hydroelectric plant, but my spring/stream is too small to be worthwhile.

 

[bobbyt]

I'd do a check on the efficiency of your existing boiler (80-85%?)& compare it with a new combi, say 95%. Then you can estimate your gas usage under the new system (say (95-80)/80 = 18% at best ) Compare that cost with the estimates you get for a change over (e.g. my son paid £3000 to change a combi boiler a couple of years back - plus two extra rads). Then you can take a view as to the payback period.
Everyone has different views on things - mine is always keep it simple! I just really wish I had my own hydroelectric plant, but my spring/stream is too small to be worthwhile.

Yep, thanks for that, when it was new the boiler was rated at 65% efficient, so probably less now. At those figures, would save 30 - 35% on my bill, if that's how it works? Which would save £400- 500 a year in theory, at today's prices. So payback on new boiler in 5 or 6 years. If that is how it all works. Seems a lot of savings on bills, but prices are high at the moment, no telling what'll happen in future.

 

[pycoed]

Yep, thanks for that, when it was new the boiler was rated at 65% efficient, so probably less now. At those figures, would save 30 - 35% on my bill, if that's how it works? Which would save £400- 500 a year in theory, at today's prices. So payback on new boiler in 5 or 6 years. If that is how it all works. Seems a lot of savings on bills, but prices are high at the moment, no telling what'll happen in future.

Really surprised an old gas boiler would be that low - even a Trianco TRG coal boiler was around 70-75% quoted anyway - perhapos that was before the Trade Descriptions Act?! I can't see gas/energy prices going down anytime soon 😢

 

[Knappers]

If budget is main consideration then like for like

Orherwise:-

;One bathroom you have a combi.

;2 bathrooms with showers and 3 beds either combi or system and unvented cylinder.

;2+ bathrooms and 4+ bedrooms then you have a system boiler and unvented cylinder.

There's good justified reasons for this but it gets a bit complicated and confusing.
Basically comes down to the benefits of a HW cylinder not coming close to being worth the extra cost in a smaller house.

(You can always fit a radiator in the airing cupboard)

 

[Knappers]

Cost wise it's normally quite simple. You won't loose or gain much financially over 10 years by fitting new, what you will get is better controls, a more comfortable home, about 10 year warranty (often without issue).
I recommend budgeting for new boiler every 15yrs and hope to get away with a few extra years

 

[Murdoch]

If you are thinking about installing pv panels then keep the hot water tank, then you can use excess electricity to produce free hot water on sunny days