Quietest Combi for Bedroom

[t23423]

Hi all,

I need to replace the combi boiler in my bedroom (can’t relocate it) and want the quietest option. I’ll build an acoustic cabinet, but I’d like to start with the best baseline.

I'm looking for around 25-35kW with hot water flow rate being an argument to go higher, but I could see demand being below 3kW/h often so maybe that's an argument to go lower?

I've seen conflicting info:

- Viessmann Vitodens 200-W: Sometimes listed as 36 dB, but the ErP label says 48 dB. One manual shows 32–33 dB at partial load, but there's no indication of what partial load actually means.

- Viessmann Vitodens 100-W: Generally said to be louder than the 200-W, but the ErP figures are almost identical. The manual listing partial load puts it basically the same as the 200-W.

- Worcester Bosch Greenstar 2000 (and 4000): I’ve seen ErP sound power of 43 dB in some places, 47 dB in others. Is the 2000 actually quieter than the 4000?

- Vaillant ecoTEC plus → Seems like another contender, but I can't find much beyond the ErP sound power and QuietMark.

From what I understand, ErP = close to max noise. Does anyone know how these models compare at lower loads, and what sort of “real-world” average noise I might expect? Are the differences between the models actually noticeable in day-to-day use?

I’m in a 2-bed flat, ~5–6 kW/h demand on cold days, so most of the time it’ll run at low output. Hot water noise is less of a concern.

If anyone has experience with these models (or better data sources), or other recommendations, I’d really appreciate your thoughts.

Thanks!

 

[Harry Bloomfield]

- Vaillant ecoTEC plus → Seems like another contender, but I can't find much beyond the ErP sound power and QuietMark.

From what I understand, ErP = close to max noise. Does anyone know how these models compare at lower loads, and what sort of “real-world” average noise I might expect? Are the differences between the models actually noticeable in day-to-day use?

We have the heat only 18kw version of the ecotec, installed in a custom high on the wall cupboard, in our kitchen, I devised from a cut down kitchen base unit. I made it long ago, to house an ancient cast iron boiler. It was simply cosmetic, I made no attempt to control the noise.

The ecotec is inaudible running, in the cupboard, I often open the door and have to stick my ear to it, to check if it is running, when it is running at low output. The purge noise of the fan, just before the boiler fires, is more clearly audible, but I would need to listen for it, to notice it, but see below.

The noise of the boiler, when first installed, was quite a bit noisier. When first installed, but only for around a month, I had it running on a basic control system, bi-metal type thermostats, for room and cylinder. On that control system, it starts and runs flat out, until it begins to satisfy the demand, and begins to ramp down it's output.

I then swapped all of that out, for Vaillant's own specialised control system, using the VRC 470 all electronic, measuring actual temperatures, and calculating how it should respond. So instead of firing and running at maximum until demand met, it throttled down from the start. Much quieter, and much more gas efficient.

 

[muggles]

Vokera Pinnacle is an excellent boiler and very quiet at 45dB(A)

 

[t23423]

We have the heat only 18kw version of the ecotec, installed in a custom high on the wall cupboard, in our kitchen, I devised from a cut down kitchen base unit. I made it long ago, to house an ancient cast iron boiler. It was simply cosmetic, I made no attempt to control the noise.

The ecotec is inaudible running, in the cupboard, I often open the door and have to stick my ear to it, to check if it is running, when it is running at low output. The purge noise of the fan, just before the boiler fires, is more clearly audible, but I would need to listen for it, to notice it, but see below.

The noise of the boiler, when first installed, was quite a bit noisier. When first installed, but only for around a month, I had it running on a basic control system, bi-metal type thermostats, for room and cylinder. On that control system, it starts and runs flat out, until it begins to satisfy the demand, and begins to ramp down it's output.

I then swapped all of that out, for Vaillant's own specialised control system, using the VRC 470 all electronic, measuring actual temperatures, and calculating how it should respond. So instead of firing and running at maximum until demand met, it throttled down from the start. Much quieter, and much more gas efficient.

Thanks for this, it's extremely helpful. My existing boiler runs flat out as you described so even knowing that can be improved on is useful and I'll make sure I get the proper control system for the boiler I get (and it's looking like the ecotec).

@muggles - thanks, I'll look into it as the Pinnacle does look very promising.

 

[gas112]

Baxi 624 mark 2

 

[muggles]

Baxi 624 mark 2

50dB so much louder, and crap modulation too

 

[gas112]

50dB so much louder, and crap modulation too

5db negligible and a far better boiler reliability and build quality brass instead of your plastic pinnacle

 

[foxhole]

Box it in , well insulated it will reduce noise .

 

[muggles]

5db negligible and a far better boiler reliability and build quality brass instead of your plastic pinnacle

5db is actually quite significant and clearly audible. As for better reliability, how many Pinnacles (which now carry a 12 year warranty) have you heard of breaking down please? Because I've seen plenty of complaints on Baxi forums saying the new ranges are nowhere near as good as the old ones

 

[gas112]

5db is actually quite significant and clearly audible. As for better reliability, how many Pinnacles (which now carry a 12 year warranty) have you heard of breaking down please? Because I've seen plenty of complaints on Baxi forums saying the new ranges are nowhere near as good as the old ones

yep heard of a few breaking down but just by sheer numbers you will see a few more baxi comments the various derivatives of the 600 series massively out sell the pinnacle and as opposed to them breaking down the vast majority of comment regards them is people not liking the prv connection and cable route .
Would much rather rely on brass than plastic which worcester has proved leak like sieves after time.

. Also all these decibel levels are only for a short time on full fire /fan and pump they all settle down very quickly to hardly audible especially if boxed in