Low loss header - Do I need it?

[monkeysballs]

Yes 9kw if that is your heat loss at -2 would keep your house at your comfort temp that you worked your heat loss out at

You wouldn't feel cold at that but if you wanted it warmer then just set the t stat to 1c higher

If you have 30kw of rad output at delta 50 (most rads output given at that ) then you could maybe run 40 or 30 so 60c or 50c flows with a 20c drop on the return temp

And bd efficient and get your house up to temp fairly quickly but how do you use your house do you work from home? Or are you only there a few hours a day?

It all feeds in to how you run your heating

Mine takes ages to warm up (could take a day to get up 5c) but mine is on basically 24x7 heating the house to 19c with a setback of 18c as I work from home so I'm here every single day all day so for me I liked to be comfortable so mine feeds it low and slow burning about 1.7kWh to keep me warm

But when we worked in an office it was on a hour in the morning and then 4 of 5 hours in the evening and honestly I'm using roughly the same amount of energy I used 43kwh yesterday and 31kwh today so far

You don't heat the cylinder and Ch at the sand time usually as they require different temperatures

I'd really suggest getting a heating engineer in to do a proper heat loss calc and design the system properly likely x plan hw priority or look at the heat engineer website and do your own heatloss calc

And I'd look at if you can improve your insulation as ultimately that's the only thing that will save you money!

 

[MNW67]

Maybe doubling it is a good rule of thumb. So 18KW.

We currently have a 21KW boiler which has worked well both when working from home and working at an office.

But I feel it's coming to the end of its life. When that happens we could drop to 18KW. Would worry going as low as 15KW. But I'll probably stick with what I know and get something roughly the same size again!

We used 140KWh yesterday on similar temperatures to you. Which ties in roughly with our respective heat losses.

 

[monkeysballs]

Yep it does

I'd look at using decent controls though not hive or nest or tado! Stick with the boiler manufacturers own ones they work much better!

 

[old duffer]

heating is a topping-up process...you heat water...to flow through a metal container..that heats the metal...that heats the air in the room...
so convection, radiation, conduction...all at the same time. An essential issue that is always missed is air change rates....you heat the air (eventually) and that air is removed and replaced....so this is on top of the traditional losses (entropy) with the outside world.

 

[old duffer]

I think it is like having a big or a small engine in a car. The small engine is more efficient. The large engine is quicker.

we are in the 21st..not the 18th

 

[old duffer]

Yep it does

I'd look at using decent controls though not hive or nest or tado! Stick with the boiler manufacturers own ones they work much better!

because they are all different and work with magic....

 

[monkeysballs]

Not sure what your meaning by that but 3rd party non opentherrm controls are garbage

Openthem controls are better but seeing as most boilers don't support opentherm properly or fully 1st party controls allow the most control of the functions