Conventional Boiler or Combi?

happy_2008

happy_2008

happy_2008

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Have moved into a 3 bed detached property (1 bath) which is still using the original boiler installed in the early 90's. Should i replace the boiler with a newer one or swap it for a combi boiler? The hot water tank is in a built in wardrobe in one of the bedrooms and it would be great to remove this to have more storage but im also aware that this change could cost around £3k or more.
 
Stick with conventional or consider a system boiler and then move it all in the loft. Spec the tank for the system to be duel coil for some future proofing for solar thermal.

Avoid combi and a new conventional boiler can adapt to hydrogen better. When they start feeding that into the grid in another 10 years :)
 
I'm surprised to see so many recommending a conventional boiler. I had my conventional boiler replaced last year, but was forced to do a like-for-like replacement due to my house using microbore piping and not fancying having to rip everything out.

Seems like it may have been the more future proof option from the above suggestions.
 
happy_2008 said:
Have moved into a 3 bed detached property (1 bath) which is still using the original boiler installed in the early 90's. Should i replace the boiler with a newer one or swap it for a combi boiler? The hot water tank is in a built in wardrobe in one of the bedrooms and it would be great to remove this to have more storage but im also aware that this change could cost around £3k or more.
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We moved from a open system boiler 1990s, to a closed and combi. 3bed property, one bathroom, we were quoted to take a 28i. If I went for a 32i to get more lpm.

We fitted a new barameteric shower recently and that addition lpm helped. Enough hot water to run the rain shower and the small shower head simultaneously - hot and cold feed is 22mm and each head is 15mm piping.
 
If the boiler still works, i'd keep it going as long as possible. When it finally dies, replace with another system boiler.

Standard boilers are cheaper, you can easily & cheaply feed excess solar energy into the hot water cylinder if you ever get a PV system; you have electric hot water immersion backup if the boiler fails suddenly, you can fit shower pumps that are precisely matched to your shower size/pressure taste so no making-do with what you get, the hot water pipework isn't constantly under mains pressure so less leaks.

There are lots of advantages of the 'old' style.
 
Conventional every time. Conventional boilers are cheaper, easier to maintain, work better with low mains pressure, and don't cause problems with your existing heating system ( such as leaking pipes, which can be a problem with a retrofitted combi boiler ). There are disadvantages to a conventional boiler but presumably you are used to those.
 
Bear in mind gas boilers are being phased out of new builds from 2025 so you may want to hang onto what you have for as long as you can then replace it with something more modern (heat pump, electric heating etc) as they become cheaper in the next few years.

I've an old system boiler from about 1985, I'd probably switch it out for a combi and have it moved up to the loft when it finally breaks for the space saving of the water tank alone, assuming the above options aren't feasible.
 
All boilers sold in 90's will be the conventional type and all sold today are of the condensing type. Condensing boilers have more electronics and other components that may affect reliability. At a minimum, the system condensing boiler will have an electric fan and a heat-exchanger as an example.

A combi boiler does away with the need for a hot water tank and also a separate pump. When converting to a combi boiler, the work required should be minimal, although the costs can mount up. One issue with a combi boiler is that it may not be able to keep up with the short term demands but has the advantage of reducing space and simplifying install.

The most common issue with a boiler is that it is seen as not being efficient. A Scottish friend, assures me that there is no real reason to be pressurized into replacing it on cost grounds since you have to pay back the additional costs. When it is seen as being uneconomic to fix, then the condensing type is really the only way to go. There are still different types of condensing boiler depending upon how much you want to put in the one unit.

Most new boilers come with a 10-year service plan which means that you pay for the boiler and then pay for it again, in return for having it annually checked/serviced. My last boiler was an old-fashioned cast-iron unit. Not very efficient but lasted 30 almost years. Most new boilers will be lucky to last 15 years. I did once come home to a flooded utility room and had to spend £6 replacing four O rings that connect the two cast-iron halves, that had perished. My new boiler didn't like the condensing pipe filling with rainwater (an installation issue and heavy rain). When it filled/flooded the repairs (covered by the 10-year warranty) have required 3 visits and most of the "internals" to be replaced. Old-style boilers will (mostly) just keep going.
 
We decided to replace our system boiler with a combi (Ideal Logic+), the primary reason was for saving space:
The location of the hot water tank/ airing cupboard was the only spot in the bathroom to put a shower due to height. Currently we have a bath under the sloping part of the roof but when we refurbish the bathroom we will now have the space to put in a shower-over-bath.
Where the cold water tank and hot water header tank were located in the loft would mean that a loft conversion would have less space in the future.
It is not a huge house so we want to maximise space where possible and this meant that two areas in our house had more space.

The cost was about £2100, including replacing a section of gas pipe that had multiple turns through the under stairs cupboard.
 
Forgot to point out i did pretty much the same thing and just got the gas certificate through this morning.

Brand new Valiant conventional boiler, replaced 6rads (really old single panel 1970s stuff) add a huge towel rail, moved the boiler into the loft, Nest installed, and replaced the cylinder just under 5k.

Massive difference to heat in the house and length of time the boiler is on. Its also one of the last houses to be built without cavity wall being available so not massively energy efficient, but Wall rock wallpaper has made a good difference.
 
Advantages of combi

- Saves space
- Cheaper (usually)
- Hot water always available

Advantages of tank

- Can more easily run multiple bathrooms or systems with more than 2 floors
- Usually easier to get a more powerful shower, particularly if you have low water pressure

I'm generally of the opinion that 3+ floor homes or low mains pressure should use a tank, whereas everyone else will probably be happiest with an over-specced combi (take whatever the recommended is for your home, add 50% to the kW rating)
 
System boiler and tank with secondary HW circulation

Being able to turn the tap on and have instant hot water is great.
Heating cold water up to just have it sitting in a 30ft pipe going cold after you've washed your hands is a bit of a waste
 
Pho said:
Bear in mind gas boilers are being phased out of new builds from 2025 so you may want to hang onto what you have for as long as you can then replace it with something more modern (heat pump, electric heating etc) as they become cheaper in the next few years.

I've an old system boiler from about 1985, I'd probably switch it out for a combi and have it moved up to the loft when it finally breaks for the space saving of the water tank alone, assuming the above options aren't feasible.
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Electric heating is terrible. The government phasing it out is incredibly short sighted. If you want to pay 3 x the amount for heating than you do on your gas system, go electric. Otherwise, stick with gas.
 
dirtychinchilla said:
Electric heating is terrible. The government phasing it out is incredibly short sighted. If you want to pay 3 x the amount for heating than you do on your gas system, go electric. Otherwise, stick with gas.
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It is in conjunction with significant requirements in insulation though. TBH the UK has been backward in building new homes for decades on this front. Mainly down to corrupt MP`s and the building lobbyest read (Tory donating building firms)
 
SPG said:
It is in conjunction with significant requirements in insulation though. TBH the UK has been backward in building new homes for decades on this front. Mainly down to corrupt MP`s and the building lobbyest read (Tory donating building firms)
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It might be, but most houses don't have that quantity of insulation. I've lived in a new build for 5 years and having electric heating would definitely have ruined our heating bills. It might be suitable for flats, but the way the legislation is written suggests that electricity has a lower carbon footprint than gas. It would if you generated it in the building in which you're using it, but as most electricity is generated elsewhere, it simply isn't true.

Heat pumps are also not as good as the government would like them to be. Engineers are sticking them in everywhere because they can tick a BREAAM or SAP box, but in reality they can only raise the water temperature a few degrees. Their seasonal efficiency is generally poor etc.
 
dirtychinchilla said:
Electric heating is terrible. The government phasing it out is incredibly short sighted. If you want to pay 3 x the amount for heating than you do on your gas system, go electric. Otherwise, stick with gas.
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Oh yeah I agree, gas is far cheaper than electric right now. But in theory, the more renewable energy we generate the cheaper it should become and hopefully will become ultra cheap in 10 years or so. Seeing how much the execs of utility companies earn, that unfortunately may not happen though

There was a scheme to look into pumping hydrogen via our existing gas pipes rather than natural gas, not sure what happened with that.
 
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