What’s more efficient if you don’t have a condensing boiler?

I have a combi boiler non -condensing but gets about 79% efficiency whatever that means. With large rooms and high ceilings the time it takes to heat each large room from overnight setback say 17.5 deg to 20 deg is more than two hours, and each small room about 70 mins. I’ve discovered in the current weather running the boiler at anything much less than 58 deg takes too long for the system to react.

Scenario 1)I have different rooms in the house drawing heat at different times eg bathroom and kitchen hot in the morning, study at lunchtime, living room hot in the evening, but when they are drawing heat the others (manual TRVS) are just ticking over. This means lots of shorter smaller burns than scenario 2


Scenario 2) I run the whole house “cooler” during the day (home office but wear jumper etc) but have the boiler come on at certain times eg breakfast / evening meal - it means that the burn time is much longer and sustained and might even take a couple of hours of pre-heat in the morning. This is also because not every rad has a TRV and they are left on 3 and therefore the water is cooled through these cool areas to get to the rads that will provide the most heat.

WHich is a better setup - im worried that the boiler wil just be on the WHOLE time with the wrong setup

Best Answer

  • GrilledCheese2
    GrilledCheese2 ✭✭✭
    edited January 2023 Answer ✓

    @hipponax1973 non-condensing boilers were designed to run at high temperatures to avoid the condensing of flu gases. If condensate is generated it will corrode the boiler inside as there is no mechanism to remove the condensate safely. Personally I would run an old boiler at 70°C minimum and enjoy the fast warm up time. Without spending extra money your best option to be efficient, is to keep the room thermostats as low as possible.

Answers

  • Hello Hippo,
    From experience of an under-rated boiler and small radiators on a single pipe system the house was b*** cold. We ran the heating 24x7. A new boiler and twin pipe system was much hotter and the recovery (heating) rate was ok.
    The basic answer is to make sure you have a new boiler and make sure the radiators are big enough
  • I have a gravity Stored Cylinder.
    This is how I set mine up.

    Immersion on a weekly timer for 30 minutes one day a week at 5am to stop it scaling.

    Hot Water 6 am every day for an hour except immersion day where it's 30 minutes.

    Then 45 minutes aboutt 6pm.

    Boiler set to 75% Tank stat to biologically.safe temperature. Thimk it's 61C

    Heating one day a week when It won't get stupidly hot, all rads to 19, central heating to 19.5 Geofencing off for that event.


    In winter.
    If you have 2 rads in a zone set them to same temperature to avoid currents.
    Heat your rooms that you use at the same time as water events to minimise boiler running periods.

    Empy roms.cycle in the morning during hot water event to minimise boiler starts, and heat should stay in the room longer in winter

    i use geofencing to trigger daytime events like mid day hot water if needed.

    If you always use your hot wster slots to boost your heating the boiler runs for slightly longer in that slot but you are getting two for one.. if you call for hest outside of water times the boiler is running specifically to heat a room.

    Also stops mould at dew point

    It works for me.
  • ahh that makes it easier as i only have on demand hot water from the tap as no tank. I’ve discover since upping the flow temp to 58 from 51 that the overall house temp coasts much better and gears quicker