Gas central heating 1970 3 bed semi

meat_n2_reg

Hello 
Fairly recently upgraded house with new double glazing windows and doors , 400mm loft insulation and new worcester bosch combi 4000 (flow temp 65c) with new radiators ; house already had cavity insulation 
Heating on from 9am to 9pm , then off overnight 
With current outside temperatures of approx 0c and heating lounge to 19c , rest of the house 17c ;
Using approx £4 of gas per day approx 65 kwh of gas 
Looking at hive boiler was heating for 3hr 48 mins out of the 12 hours 
Works out at approx 35p per hour which seems good to me 
Just wondering if this was excessive or fairly normal ?
Thanks 

QrizB

Sounds quite typical.

My 1950s semi with less insulation has used 70kWh of gas  so far today, again with outdoor temps around freezing and indoor around 19.

Bendo

Hive won't be doing you any favours. If it's a new boiler then it's designed to modulate down for efficiency. Hive just runs it full pelt. Then turns it off let's everything get cold then repeat.

Great for British Gas profits, not great for anything else.

Hive has its place, controlling a modern boiler absolutely isn't it though.

FreeBear

Similar temperatures here in a slightly older 3 bed semi. Used just under 34kWh of gas today over 6hr 30min burn time. Running at a flow temperature of 50°C, so heating low & slow (generated 31kWh of heat).

If you had the foresight to specify oversized radiators, it is well worth dialing back the flow temperature so that the boiler is pushed further in to condensing mode - To be more precise, it is the return temperature that wants to be as low as practical. It will help if the radiators are balanced properly and the pump speed turned down to suit.

Keep_pedalling

FreeBear said:

Similar temperatures here in a slightly older 3 bed semi. Used just under 34kWh of gas today over 6hr 30min burn time. Running at a flow temperature of 50°C, so heating low & slow (generated 31kWh of heat).

If you had the foresight to specify oversized radiators, it is well worth dialing back the flow temperature so that the boiler is pushed further in to condensing mode - To be more precise, it is the return temperature that wants to be as low as practical. It will help if the radiators are balanced properly and the pump speed turned down to suit.

What room temperatures?

FreeBear

Keep_pedalling said:

FreeBear said:

Similar temperatures here in a slightly older 3 bed semi. Used just under 34kWh of gas today over 6hr 30min burn time. Running at a flow temperature of 50°C, so heating low & slow (generated 31kWh of heat).

If you had the foresight to specify oversized radiators, it is well worth dialing back the flow temperature so that the boiler is pushed further in to condensing mode - To be more precise, it is the return temperature that wants to be as low as practical. It will help if the radiators are balanced properly and the pump speed turned down to suit.

What room temperatures?

Much of the house at a steady 19°C (+/- 0.2°C). Just the kitchen, bathroom, & dining room down to ~18°C.

lohr500

Bendo said:

Hive won't be doing you any favours. If it's a new boiler then it's designed to modulate down for efficiency. Hive just runs it full pelt. Then turns it off let's everything get cold then repeat.

Great for British Gas profits, not great for anything else.

Hive has its place, controlling a modern boiler absolutely isn't it though.

I'm keen to learn more.

I thought boiler modulation was controlled by the boiler itself based on monitoring flow and return temperatures.
And that the Hive, or any other conventional room thermostat simply tells the boiler when to provide heat.

Wouldn't any room thermostat shut the boiler down once the room temperature is achieved?

Or do smarter room thermostats directly control the boiler modulation in advance of the set room temperature being achieved?
 

FreeBear

lohr500 said:

Bendo said:

Hive won't be doing you any favours. If it's a new boiler then it's designed to modulate down for efficiency. Hive just runs it full pelt. Then turns it off let's everything get cold then repeat.

Great for British Gas profits, not great for anything else.

Hive has its place, controlling a modern boiler absolutely isn't it though.

I'm keen to learn more.

I thought boiler modulation was controlled by the boiler itself based on monitoring flow and return temperatures.
And that the Hive, or any other conventional room thermostat simply tells the boiler when to provide heat.

Wouldn't any room thermostat shut the boiler down once the room temperature is achieved?

Or do smarter room thermostats directly control the boiler modulation in advance of the set room temperature being achieved?
 

With my boiler, the thermostat instructs the boiler what temperature the water should be. The boiler then adjusts the fan speed & gas flow (modulates) to maintain the commanded temperature. The commanded temperature could be anywhere from 35°C (could go lower) all the way up to 70°C (absolute max is 80°C). Most of the time, the thermostat calls for heat and slowly ramps up the commanded temperature to 50-55°C and then ramps down as the room temperature is reached. If the minimum output of the boiler is less than the heat loss of the building, the control would reach a state of equilibrium and output will match heat loss.

If I were to disable OpenTherm* and use a basic on/off control, the flow temperature would be set via the boiler control panel (currently 60°C). The boiler would still modulate, but it wouldn't be as flexible in ramping up & down. Without feedback via commanded water temperature, the boiler has no way of knowing that the room set point has been reached, so will continue to try and maintain the 60°C flow temperature.

One point to bear in mind - On firing up, gas consumption will be at its highest, and the components inside the boiler will be subjected to higher stresses (fan running at full speed, heat exchanger subjected to rapid heating, etc). With smarter control, slowly ramping up boiler temperature reduces these stresses peak gas consumption.

*) Worcester Bosch uses their own version of OpenTherm called EMS - Incompatible with OpenTherm, so you need to be careful when selecting a smarter thermostat.

meat_n2_reg

Tried turning thermostat down  by 1c today , lounge 18c , rest of the house 16c
used approx £3 of gas and approx 50kw 
Hive run time of 2hr 54 out of 12 hours cost 25p per hour 

I have reduced flow temp to 60c and will check usage tomorrow 

Had a look at a smart thermometer that is compatible with Worcester Bosch boiler and choice seems limited 

Found this one https://www.worcester-bosch.co.uk/products/boiler-controls/bosch-easycontrol

Regards Steve 

Gerry1

meat_n2_reg said:
used approx £3 of gas and approx 50kw

Nope, 50kWh !