maximizing combi boiler efficiency

[Paul]

with the recent rise in gas prices and the possibility of further increases i am after tips as to how to run a combi boiler with greatest efficiency. I have a large 3 bed semi with cavity walls eight rads 6 with trv's. the ones without are in the bathroom and kitchen. the boiler is a chaffoteux et maury mx2. i have recently fitted a programmable stat in the hall near the kitchen. the main question really is what to set the water and heating temperature to on the front of the boiler. i have read on one website that for max efficiency set both to max. is this correct?

Paul.

[Ian Stirling]

Is this a condensing boiler?

[Paul]

No its non condensing

[Ian Stirling]

Ok. For a condensing boiler, there is a tradeoff between output temperature and efficiency. Not so for a non-condensing one (so much, still a tiny effect).

Setting the hot water temp lower can be good. If you run a tap for hot water, then you (a lot of the time) end up with the n litres in the pipe after the water has got hot enough simply going cold, and the energy often being wasted, as it's sometimes not very well insulated to the outside. If you set the hot water temp as low as you will ever need hot water, then instead of the water in the pipe being at 70C, it's at 45C, and you only lose about 60% of the energy you otherwise would.

[IMM]

It appears you have gone as far as you can with the system. Now it is a matter of installing more insulation. Put 1 foot in the loft. Then use a silicon gun and get rid of air leaks.

[Andy Hall]

It's non condensing and near the low end of the SEDBUK range on efficiency.

Non-condensing boilers are designed to run hot to avoid condensation and corrosion, so the thermostat should be set to max.

There is little that one can do about the running efficiency of the boiler, but only matching its usage to the required temperatures in the house.

The OP already has TRVs. If the programmable stat is optimising, then a small gain in usage behaviour may be able to be gained.

That is really about it with this type of boiler.

.andy

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[Andy Hall]

Not forgetting to insulate the cavity walls if that has not already been done since they exhibit a far larger loss of heat than a loft with even some insulation.

.andy

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[IMM]

And cost a lot more. Loft and air leaks is DIY.

[Andy Hall]

Actually you can get subsidised installations for both.

Are you saying that cavity insulation isn't worth doing?

.andy

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[The Natural Philosopher]

For maxiumum efficiency, shove it in a skip.

It's then operating at zero input and zero output, and efficiency of 100%.

[Mike Clarke]

Or zero efficiency if you prefer

0 (input) x 0 (efficiency) = 0 (output)

:-)