How to improve heating system

theoretica

As others have said, sort out the radiator valves and a thermostat as your first targets.  I am considering swapping out a few radiators for bigger ones so I can run my heating year round at a cooler water temperature where the boiler is most efficient.

Rosabear

coffeehound said:

Hello.  Do you have a hot water tank?  What is the thermostat set to, if so?

For the non-working TRVs, have you tried unscrewing the tops?

No its a combi boiler. Yes tried unscrewing but they're very tight so no joy.

Rosabear

Ally_E. said:

That's a normal usage for such a big house if it's older build, like a period property? We use 132kW a day in our 1930s solid brick wall house, 3 bedrooms. Thermostat at 18C and boiler on 40C return flow temperature, so condensing nicely and working efficiently. 

Ah that is interesting, thank you. It's so difficult to know what's normal and what's not when you move to quite a different property. Our old house was actually older than this one but definitely smaller.

Rosabear

theoretica said:

As others have said, sort out the radiator valves and a thermostat as your first targets.  I am considering swapping out a few radiators for bigger ones so I can run my heating year round at a cooler water temperature where the boiler is most efficient.

Can you explain how that works? What temp should I be aiking for? Some of the rads are very small here.

theoretica

Rosabear said:

theoretica said:

As others have said, sort out the radiator valves and a thermostat as your first targets.  I am considering swapping out a few radiators for bigger ones so I can run my heating year round at a cooler water temperature where the boiler is most efficient.

Can you explain how that works? What temp should I be aiking for? Some of the rads are very small here.

Combi boilers nowadays 'condense', which means they should put much less heat out the flu, but that only works if the water coming back from going round the heating system is cool enough (absolute maximum 55 degrees C, cooler is better).  When this is working properly the flu doesn't put out clouds of steam.  There are two ways to get this return water cool enough - one is getting lots of heat out of the water and into the rooms (so large radiators) and the other is having a lower temperature on water coming out of the boiler (which needs large radiators if not to have cold rooms). 

Rosabear

theoretica said:

Rosabear said:

theoretica said:

As others have said, sort out the radiator valves and a thermostat as your first targets.  I am considering swapping out a few radiators for bigger ones so I can run my heating year round at a cooler water temperature where the boiler is most efficient.

Can you explain how that works? What temp should I be aiking for? Some of the rads are very small here.

Combi boilers nowadays 'condense', which means they should put much less heat out the flu, but that only works if the water coming back from going round the heating system is cool enough (absolute maximum 55 degrees C, cooler is better).  When this is working properly the flu doesn't put out clouds of steam.  There are two ways to get this return water cool enough - one is getting lots of heat out of the water and into the rooms (so large radiators) and the other is having a lower temperature on water coming out of the boiler (which needs large radiators if not to have cold rooms). 

Oh I understand you. Thanks! Yes the boiler is forever pumping out steam so I'll try turning it down a bit more.

FreeBear

Rosabear said:

coffeehound said:

Hello.  Do you have a hot water tank?  What is the thermostat set to, if so?

For the non-working TRVs, have you tried unscrewing the tops?

No its a combi boiler. Yes tried unscrewing but they're very tight so no joy.

Get yourself something like this - https://www.roys.co.uk/zyliss-strongboy-2-jar-opener - Handy thing to have in the kitchen and useful for other jobs.

Radiator sizing - There are a number of online calculators available. Some better than others. Look for one that asks plenty of questions beyond the size of the room. Also look to see what ΔT (or Delta T) is used. The ΔT is the temperature difference between ambient room temperature and the CH water temperature. For most gas systems, this is 50°C, but if you run the CH at a lower temperature (for example, with a ASHP), the heat output of a radiator will be lower. So a lower water temperature requires a larger radiator for the same heat output.

BUFF

Rosabear said:

Ally_E. said:

That's a normal usage for such a big house if it's older build, like a period property? We use 132kW a day in our 1930s solid brick wall house, 3 bedrooms. Thermostat at 18C and boiler on 40C return flow temperature, so condensing nicely and working efficiently. 

Ah that is interesting, thank you. It's so difficult to know what's normal and what's not when you move to quite a different property. Our old house was actually older than this one but definitely smaller.

Your terrace (depending upon actual design) shouldn't use as much energy as a detached house though as you have shared walls with your neighbours & as long as they are heating their houses to the same temp as yours you can treat those as perfect insulators. If you run your house cooler you can even gain a little heat from your neighbours. 

As a comparison, I live in a 3-bed Edwardian solid-walled terrace in a conservation area (so not allowed to do some things like double glazing to the front etc.) in Glasgow (reasonably north) but most of the low hanging fruit of loft insulation, draughtproofing etc. have been done. I have a condensing combi boiler set up with low flow temps, I wear an extra layer and admittedly I am happy at a lower temp than many people would find comfortable - I typically use 7500-8500kWh of gas per year depending upon ambient weather for heat & hot water. As an example in January 2022 I used 1205kWh - it was a fairly mild January though.